diff --git a/w3c/css/CSS.json b/w3c/css/CSS.json
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+{
+  "properties": {
+    "margin-top": {
+      "name": "margin-top",
+      "value": "<margin-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except elements with table display types other than table-caption, table and inline-table",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "margin-bottom": {
+      "name": "margin-bottom",
+      "value": "<margin-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except elements with table display types other than table-caption, table and inline-table",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "margin-right": {
+      "name": "margin-right",
+      "value": "<margin-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except elements with table display types other than table-caption, table and inline-table",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "margin-left": {
+      "name": "margin-left",
+      "value": "<margin-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except elements with table display types other than table-caption, table and inline-table",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "margin": {
+      "name": "margin",
+      "value": "<margin-width>{1,4} | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements except elements with table display types other than table-caption, table and inline-table",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "padding-top": {
+      "name": "padding-top",
+      "value": "<padding-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except table-row-group, table-header-group, table-footer-group, table-row, table-column-group and table-column",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "padding-right": {
+      "name": "padding-right",
+      "value": "<padding-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except table-row-group, table-header-group, table-footer-group, table-row, table-column-group and table-column",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "padding-bottom": {
+      "name": "padding-bottom",
+      "value": "<padding-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except table-row-group, table-header-group, table-footer-group, table-row, table-column-group and table-column",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "padding-left": {
+      "name": "padding-left",
+      "value": "<padding-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except table-row-group, table-header-group, table-footer-group, table-row, table-column-group and table-column",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "padding": {
+      "name": "padding",
+      "value": "<padding-width>{1,4} | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements except table-row-group, table-header-group, table-footer-group, table-row, table-column-group and table-column",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border-top-width": {
+      "name": "border-top-width",
+      "value": "<border-width> | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "absolute length; '0' if the border style is 'none' or 'hidden'"
+    },
+    "border-right-width": {
+      "name": "border-right-width",
+      "value": "<border-width> | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "absolute length; '0' if the border style is 'none' or 'hidden'"
+    },
+    "border-bottom-width": {
+      "name": "border-bottom-width",
+      "value": "<border-width> | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "absolute length; '0' if the border style is 'none' or 'hidden'"
+    },
+    "border-left-width": {
+      "name": "border-left-width",
+      "value": "<border-width> | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "absolute length; '0' if the border style is 'none' or 'hidden'"
+    },
+    "border-width": {
+      "name": "border-width",
+      "value": "<border-width>{1,4} | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border-top-color": {
+      "name": "border-top-color",
+      "value": "<color> | transparent | inherit",
+      "initial": "the value of the 'color' property",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "when taken from the 'color' property, the computed value of 'color'; otherwise, as specified"
+    },
+    "border-right-color": {
+      "name": "border-right-color",
+      "value": "<color> | transparent | inherit",
+      "initial": "the value of the 'color' property",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "when taken from the 'color' property, the computed value of 'color'; otherwise, as specified"
+    },
+    "border-bottom-color": {
+      "name": "border-bottom-color",
+      "value": "<color> | transparent | inherit",
+      "initial": "the value of the 'color' property",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "when taken from the 'color' property, the computed value of 'color'; otherwise, as specified"
+    },
+    "border-left-color": {
+      "name": "border-left-color",
+      "value": "<color> | transparent | inherit",
+      "initial": "the value of the 'color' property",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "when taken from the 'color' property, the computed value of 'color'; otherwise, as specified"
+    },
+    "border-color": {
+      "name": "border-color",
+      "value": "[ <color> | transparent ]{1,4} | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border-top-style": {
+      "name": "border-top-style",
+      "value": "<border-style> | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "border-right-style": {
+      "name": "border-right-style",
+      "value": "<border-style> | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "border-bottom-style": {
+      "name": "border-bottom-style",
+      "value": "<border-style> | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "border-left-style": {
+      "name": "border-left-style",
+      "value": "<border-style> | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "border-style": {
+      "name": "border-style",
+      "value": "<border-style>{1,4} | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border-top": {
+      "name": "border-top",
+      "value": "[ <border-width> || <border-style> || <'border-top-color'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border-right": {
+      "name": "border-right",
+      "value": "[ <border-width> || <border-style> || <'border-top-color'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border-bottom": {
+      "name": "border-bottom",
+      "value": "[ <border-width> || <border-style> || <'border-top-color'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border-left": {
+      "name": "border-left",
+      "value": "[ <border-width> || <border-style> || <'border-top-color'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border": {
+      "name": "border",
+      "value": "[ <border-width> || <border-style> || <'border-top-color'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "display": {
+      "name": "display",
+      "value": "inline | block | list-item | inline-block | table | inline-table | table-row-group | table-header-group | table-footer-group | table-row | table-column-group | table-column | table-cell | table-caption | none | inherit",
+      "initial": "inline",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "all",
+      "computed value": "see text"
+    },
+    "position": {
+      "name": "position",
+      "value": "static | relative | absolute | fixed | inherit",
+      "initial": "static",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "top": {
+      "name": "top",
+      "value": "<length> | <percentage> | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "media": "visual",
+      "computed value": "if specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, 'auto'."
+    },
+    "right": {
+      "name": "right",
+      "value": "<length> | <percentage> | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "if specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, 'auto'."
+    },
+    "bottom": {
+      "name": "bottom",
+      "value": "<length> | <percentage> | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "media": "visual",
+      "computed value": "if specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, 'auto'."
+    },
+    "left": {
+      "name": "left",
+      "value": "<length> | <percentage> | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "if specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, 'auto'."
+    },
+    "float": {
+      "name": "float",
+      "value": "left | right | none | inherit",
+      "initial": "none",
+      "appliesTo": "all, but see 9.7",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "clear": {
+      "name": "clear",
+      "value": "none | left | right | both | inherit",
+      "initial": "none",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "z-index": {
+      "name": "z-index",
+      "value": "auto | <integer> | inherit",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "direction": {
+      "name": "direction",
+      "value": "ltr | rtl | inherit",
+      "initial": "ltr",
+      "appliesTo": "all elements, but see prose",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "unicode-bidi": {
+      "name": "unicode-bidi",
+      "value": "normal | embed | bidi-override | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements, but see prose",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "width": {
+      "name": "width",
+      "value": "<length> | <percentage> | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "all elements but non-replaced inline elements, table rows, and row groups",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage or 'auto' as specified or the absolute length"
+    },
+    "min-width": {
+      "name": "min-width",
+      "value": "<length> | <percentage> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements but non-replaced inline elements, table rows, and row groups",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "max-width": {
+      "name": "max-width",
+      "value": "<length> | <percentage> | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements but non-replaced inline elements, table rows, and row groups",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length or 'none'"
+    },
+    "height": {
+      "name": "height",
+      "value": "<length> | <percentage> | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "all elements but non-replaced inline elements, table columns, and column groups",
+      "inherited": "no",
+      "percentages": "see prose",
+      "media": "visual",
+      "computed value": "the percentage or 'auto' (see prose under <percentage>) or the absolute length"
+    },
+    "min-height": {
+      "name": "min-height",
+      "value": "<length> | <percentage> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements but non-replaced inline elements, table columns, and column groups",
+      "inherited": "no",
+      "percentages": "see prose",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "max-height": {
+      "name": "max-height",
+      "value": "<length> | <percentage> | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements but non-replaced inline elements, table columns, and column groups",
+      "inherited": "no",
+      "percentages": "see prose",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length or 'none'"
+    },
+    "line-height": {
+      "name": "line-height",
+      "value": "normal | <number> | <length> | <percentage> | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "refer to the font size of the element itself",
+      "media": "visual",
+      "computed value": "for <length> and <percentage> the absolute value; otherwise as specified"
+    },
+    "vertical-align": {
+      "name": "vertical-align",
+      "value": "baseline | sub | super | top | text-top | middle | bottom | text-bottom | <percentage> | <length> | inherit",
+      "initial": "baseline",
+      "appliesTo": "inline-level and 'table-cell' elements",
+      "inherited": "no",
+      "percentages": "refer to the 'line-height' of the element itself",
+      "media": "visual",
+      "computed value": "for <percentage> and <length> the absolute length, otherwise as specified"
+    },
+    "overflow": {
+      "name": "overflow",
+      "value": "visible | hidden | scroll | auto | inherit",
+      "initial": "visible",
+      "appliesTo": "block containers",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "clip": {
+      "name": "clip",
+      "value": "<shape> | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "absolutely positioned elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "'auto' if specified as 'auto', otherwise a rectangle with four values, each of which is 'auto' if specified as 'auto' and the computed length otherwise"
+    },
+    "visibility": {
+      "name": "visibility",
+      "value": "visible | hidden | collapse | inherit",
+      "initial": "visible",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "content": {
+      "name": "content",
+      "value": "normal | none | [ <string> | <uri> | <counter> | attr(<identifier>) | open-quote | close-quote | no-open-quote | no-close-quote ]+ | inherit",
+      "initial": "normal",
+      "appliesTo": ":before and :after pseudo-elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "all",
+      "computed value": "On elements, always computes to 'normal'. On :before and :after, if 'normal' is specified, computes to 'none'. Otherwise, for URI values, the absolute URI; for attr() values, the resulting string; for other keywords, as specified."
+    },
+    "quotes": {
+      "name": "quotes",
+      "value": "[<string> <string>]+ | none | inherit",
+      "initial": "depends on user agent",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "counter-reset": {
+      "name": "counter-reset",
+      "value": "[ <identifier> <integer>? ]+ | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "all",
+      "computed value": "as specified"
+    },
+    "counter-increment": {
+      "name": "counter-increment",
+      "value": "[ <identifier> <integer>? ]+ | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "all",
+      "computed value": "as specified"
+    },
+    "list-style-type": {
+      "name": "list-style-type",
+      "value": "disc | circle | square | decimal | decimal-leading-zero | lower-roman | upper-roman | lower-greek | lower-latin | upper-latin | armenian | georgian | lower-alpha | upper-alpha | none | inherit",
+      "initial": "disc",
+      "appliesTo": "elements with 'display: list-item'",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "list-style-image": {
+      "name": "list-style-image",
+      "value": "<uri> | none | inherit",
+      "initial": "none",
+      "appliesTo": "elements with 'display: list-item'",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "absolute URI or 'none'"
+    },
+    "list-style-position": {
+      "name": "list-style-position",
+      "value": "inside | outside | inherit",
+      "initial": "outside",
+      "appliesTo": "elements with 'display: list-item'",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "list-style": {
+      "name": "list-style",
+      "value": "[ <'list-style-type'> || <'list-style-position'> || <'list-style-image'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "elements with 'display: list-item'",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "page-break-before": {
+      "name": "page-break-before",
+      "value": "auto | always | avoid | left | right | inherit",
+      "initial": "auto",
+      "appliesTo": "block-level elements (but see text)",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual, paged",
+      "computed value": "as specified"
+    },
+    "page-break-after": {
+      "name": "page-break-after",
+      "value": "auto | always | avoid | left | right | inherit",
+      "initial": "auto",
+      "appliesTo": "block-level elements (but see text)",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual, paged",
+      "computed value": "as specified"
+    },
+    "page-break-inside": {
+      "name": "page-break-inside",
+      "value": "avoid | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "block-level elements (but see text)",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual, paged",
+      "computed value": "as specified"
+    },
+    "orphans": {
+      "name": "orphans",
+      "value": "<integer> | inherit",
+      "initial": "2",
+      "appliesTo": "block container elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual, paged",
+      "computed value": "as specified"
+    },
+    "widows": {
+      "name": "widows",
+      "value": "<integer> | inherit",
+      "initial": "2",
+      "appliesTo": "block container elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual, paged",
+      "computed value": "as specified"
+    },
+    "color": {
+      "name": "color",
+      "value": "<color> | inherit",
+      "initial": "depends on user agent",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "background-color": {
+      "name": "background-color",
+      "value": "<color> | transparent | inherit",
+      "initial": "transparent",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "background-image": {
+      "name": "background-image",
+      "value": "<uri> | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "absolute URI or none"
+    },
+    "background-repeat": {
+      "name": "background-repeat",
+      "value": "repeat | repeat-x | repeat-y | no-repeat | inherit",
+      "initial": "repeat",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "background-attachment": {
+      "name": "background-attachment",
+      "value": "scroll | fixed | inherit",
+      "initial": "scroll",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "background-position": {
+      "name": "background-position",
+      "value": "[ [ <percentage> | <length> | left | center | right ] [ <percentage> | <length> | top | center | bottom ]? ] | [ [ left | center | right ] || [ top | center | bottom ] ] | inherit",
+      "initial": "0% 0%",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to the size of the box itself",
+      "media": "visual",
+      "computed value": "for <length> the absolute value, otherwise a percentage"
+    },
+    "background": {
+      "name": "background",
+      "value": "[<'background-color'> || <'background-image'> || <'background-repeat'> || <'background-attachment'> || <'background-position'>] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "allowed on 'background-position'",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "font-family": {
+      "name": "font-family",
+      "value": "[[ <family-name> | <generic-family> ] [, <family-name>| <generic-family>]* ] | inherit",
+      "initial": "depends on user agent",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "font-style": {
+      "name": "font-style",
+      "value": "normal | italic | oblique | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "font-variant": {
+      "name": "font-variant",
+      "value": "normal | small-caps | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "font-weight": {
+      "name": "font-weight",
+      "value": "normal | bold | bolder | lighter | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see text"
+    },
+    "font-size": {
+      "name": "font-size",
+      "value": "<absolute-size> | <relative-size> | <length> | <percentage> | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "refer to inherited font size",
+      "media": "visual",
+      "computed value": "absolute length"
+    },
+    "font": {
+      "name": "font",
+      "value": "[ [ <'font-style'> || <'font-variant'> || <'font-weight'> ]? <'font-size'> [ / <'line-height'> ]? <'font-family'> ] | caption | icon | menu | message-box | small-caption | status-bar | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "see individual properties",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "text-indent": {
+      "name": "text-indent",
+      "value": "<length> | <percentage> | inherit",
+      "initial": "0",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "text-align": {
+      "name": "text-align",
+      "value": "left | right | center | justify | inherit",
+      "initial": "a nameless value that acts as 'left' if 'direction' is 'ltr', 'right' if 'direction' is 'rtl'",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "the initial value or as specified"
+    },
+    "text-decoration": {
+      "name": "text-decoration",
+      "value": "none | [ underline || overline || line-through || blink ] | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no (see prose)",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "letter-spacing": {
+      "name": "letter-spacing",
+      "value": "normal | <length> | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "'normal' or absolute length"
+    },
+    "word-spacing": {
+      "name": "word-spacing",
+      "value": "normal | <length> | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "for 'normal' the value '0'; otherwise the absolute length"
+    },
+    "text-transform": {
+      "name": "text-transform",
+      "value": "capitalize | uppercase | lowercase | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "white-space": {
+      "name": "white-space",
+      "value": "normal | pre | nowrap | pre-wrap | pre-line | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "caption-side": {
+      "name": "caption-side",
+      "value": "top | bottom | inherit",
+      "initial": "top",
+      "appliesTo": "'table-caption' elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "table-layout": {
+      "name": "table-layout",
+      "value": "auto | fixed | inherit",
+      "initial": "auto",
+      "appliesTo": "'table' and 'inline-table' elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "border-collapse": {
+      "name": "border-collapse",
+      "value": "collapse | separate | inherit",
+      "initial": "separate",
+      "appliesTo": "'table' and 'inline-table' elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "border-spacing": {
+      "name": "border-spacing",
+      "value": "<length> <length>? | inherit",
+      "initial": "0",
+      "appliesTo": "'table' and 'inline-table' elements*",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "two absolute lengths"
+    },
+    "empty-cells": {
+      "name": "empty-cells",
+      "value": "show | hide | inherit",
+      "initial": "show",
+      "appliesTo": "'table-cell' elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "cursor": {
+      "name": "cursor",
+      "value": "[ [<uri> ,]* [ auto | crosshair | default | pointer | move | e-resize | ne-resize | nw-resize | n-resize | se-resize | sw-resize | s-resize | w-resize | text | wait | help | progress ] ] | inherit",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual, interactive",
+      "computed value": "as specified, except with any relative URLs converted to absolute"
+    },
+    "outline": {
+      "name": "outline",
+      "value": "[ <'outline-color'> || <'outline-style'> || <'outline-width'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual, interactive",
+      "computed value": "see individual properties"
+    },
+    "outline-width": {
+      "name": "outline-width",
+      "value": "<border-width> | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual, interactive",
+      "computed value": "absolute length; '0' if the outline style is 'none'"
+    },
+    "outline-style": {
+      "name": "outline-style",
+      "value": "<border-style> | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual, interactive",
+      "computed value": "as specified"
+    },
+    "outline-color": {
+      "name": "outline-color",
+      "value": "<color> | invert | inherit",
+      "initial": "invert",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual, interactive",
+      "computed value": "as specified"
+    },
+    "volume": {
+      "name": "volume",
+      "value": "<number> | <percentage> | silent | x-soft | soft | medium | loud | x-loud | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "refer to inherited value",
+      "media": "aural",
+      "computed value": "number"
+    },
+    "speak": {
+      "name": "speak",
+      "value": "normal | none | spell-out | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    },
+    "pause-before": {
+      "name": "pause-before",
+      "value": "<time> | <percentage> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "see prose",
+      "media": "aural",
+      "computed value": "time"
+    },
+    "pause-after": {
+      "name": "pause-after",
+      "value": "<time> | <percentage> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "see prose",
+      "media": "aural",
+      "computed value": "time;;"
+    },
+    "pause": {
+      "name": "pause",
+      "value": "[ [<time> | <percentage>]{1,2} ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "see descriptions of 'pause-before' and 'pause-after'",
+      "media": "aural",
+      "computed value": "see individual properties"
+    },
+    "cue-before": {
+      "name": "cue-before",
+      "value": "<uri> | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "absolute URI or 'none'"
+    },
+    "cue-after": {
+      "name": "cue-after",
+      "value": "<uri> | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "absolute URI or 'none'"
+    },
+    "cue": {
+      "name": "cue",
+      "value": "[ <'cue-before'> || <'cue-after'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "see individual properties"
+    },
+    "play-during": {
+      "name": "play-during",
+      "value": "<uri> [ mix || repeat ]? | auto | none | inherit",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "absolute URI, rest as specified"
+    },
+    "azimuth": {
+      "name": "azimuth",
+      "value": "<angle> | [[ left-side | far-left | left | center-left | center | center-right | right | far-right | right-side ] || behind ] | leftwards | rightwards | inherit",
+      "initial": "center",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "normalized angle"
+    },
+    "elevation": {
+      "name": "elevation",
+      "value": "<angle> | below | level | above | higher | lower | inherit",
+      "initial": "level",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "normalized angle"
+    },
+    "speech-rate": {
+      "name": "speech-rate",
+      "value": "<number> | x-slow | slow | medium | fast | x-fast | faster | slower | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "number"
+    },
+    "voice-family": {
+      "name": "voice-family",
+      "value": "[[<specific-voice> | <generic-voice> ],]* [<specific-voice> | <generic-voice> ] | inherit",
+      "initial": "depends on user agent",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    },
+    "pitch": {
+      "name": "pitch",
+      "value": "<frequency> | x-low | low | medium | high | x-high | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "frequency"
+    },
+    "pitch-range": {
+      "name": "pitch-range",
+      "value": "<number> | inherit",
+      "initial": "50",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    },
+    "stress": {
+      "name": "stress",
+      "value": "<number> | inherit",
+      "initial": "50",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    },
+    "richness": {
+      "name": "richness",
+      "value": "<number> | inherit",
+      "initial": "50",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    },
+    "speak-punctuation": {
+      "name": "speak-punctuation",
+      "value": "code | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    },
+    "speak-numeral": {
+      "name": "speak-numeral",
+      "value": "digits | continuous | inherit",
+      "initial": "continuous",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    },
+    "speak-header": {
+      "name": "speak-header",
+      "value": "once | always | inherit",
+      "initial": "once",
+      "appliesTo": "elements that have table header information",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/SVG.json b/w3c/css/SVG.json
new file mode 100644
index 000000000000..2171481ca404
--- /dev/null
+++ b/w3c/css/SVG.json
@@ -0,0 +1,434 @@
+{
+  "properties": {
+    "cx": {
+      "name": "cx",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "‘circle’ and ‘ellipse’",
+      "inherited": "no",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computedValue": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "cy": {
+      "name": "cy",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "‘circle’ and ‘ellipse’",
+      "inherited": "no",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computedValue": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "r": {
+      "name": "r",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "‘circle’",
+      "inherited": "no",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computedValue": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "rx": {
+      "name": "rx",
+      "value": "<length-percentage> | auto",
+      "initial": "auto",
+      "appliesTo": "‘ellipse’, ‘rect’",
+      "inherited": "no",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computedValue": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "ry": {
+      "name": "ry",
+      "value": "<length-percentage> | auto",
+      "initial": "auto",
+      "appliesTo": "‘ellipse’, ‘rect’",
+      "inherited": "no",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computedValue": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "x": {
+      "name": "x",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "‘svg’, ‘rect’, ‘image’, ‘foreignObject’",
+      "inherited": "no",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computedValue": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "y": {
+      "name": "y",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "‘svg’, ‘rect’, ‘image’, ‘foreignObject’",
+      "inherited": "no",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computedValue": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "vector-effect": {
+      "name": "vector-effect",
+      "value": "none | [ non-scaling-stroke | non-scaling-size | non-rotation | fixed-position ]+ [ viewport | screen ]?",
+      "initial": "none",
+      "appliesTo": "graphics elements and ‘use’",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "d": {
+      "name": "d",
+      "value": "none | <string>",
+      "initial": "none",
+      "appliesTo": "‘path’",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "inline-size": {
+      "name": "inline-size",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "‘text’ elements",
+      "inherited": "no",
+      "percentages": "Refer to the width (for horizontal text) or height (for vertical text) of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "shape-inside": {
+      "name": "shape-inside",
+      "value": "auto | [ <basic-shape> | <uri> ]+",
+      "initial": "auto",
+      "appliesTo": "‘text’ elements",
+      "inherited": "no",
+      "percentages": "Relative to the ‘viewBox’",
+      "media": "visual",
+      "computed value": "computed lengths for <shape>, the absolute URI for <uri>, otherwise as specified",
+      "animatable": "yes, see Interpolation of Basic Shapes"
+    },
+    "shape-subtract": {
+      "name": "shape-subtract",
+      "value": "none | [ <basic-shape>| <uri> ]+",
+      "initial": "none",
+      "appliesTo": "‘text’ elements",
+      "inherited": "no",
+      "percentages": "Relative to the ‘viewBox’",
+      "media": "visual",
+      "computed value": "computed lengths for any <basic-shape>, the absolute URI for <uri>, otherwise as specified",
+      "animatable": "yes, see Interpolation of Basic Shapes"
+    },
+    "shape-margin": {
+      "name": "shape-margin",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "‘text’ elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "the absolute length",
+      "animatable": "yes"
+    },
+    "text-anchor": {
+      "name": "text-anchor",
+      "value": "start | middle | end",
+      "initial": "start",
+      "appliesTo": "text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "text-decoration-fill": {
+      "name": "text-decoration-fill",
+      "value": "<paint>",
+      "initial": "See prose.",
+      "appliesTo": "text content elements",
+      "inherited": "See prose.",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <color> values computed and <url> values made absolute.",
+      "animatable": "yes"
+    },
+    "text-decoration-stroke": {
+      "name": "text-decoration-stroke",
+      "value": "<paint>",
+      "initial": "See prose.",
+      "appliesTo": "text content elements",
+      "inherited": "See prose.",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <color> values computed and <url> values made absolute.",
+      "animatable": "yes"
+    },
+    "fill": {
+      "name": "fill",
+      "value": "<paint>",
+      "initial": "black",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <color> values computed and <url> values made absolute",
+      "animatable": "yes"
+    },
+    "fill-rule": {
+      "name": "fill-rule",
+      "value": "nonzero | evenodd",
+      "initial": "nonzero",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "fill-opacity": {
+      "name": "fill-opacity",
+      "value": "<alpha-value>",
+      "initial": "1",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "the specified value converted to a number, clamped to the range [0,1]",
+      "animatable": "yes"
+    },
+    "stroke": {
+      "name": "stroke",
+      "value": "<paint>",
+      "initial": "none",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <color> values computed and <url> values made absolute",
+      "animatable": "yes"
+    },
+    "stroke-opacity": {
+      "name": "stroke-opacity",
+      "value": "<alpha-value>",
+      "initial": "1",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "the specified value converted to a number, clamped to the range [0,1]",
+      "animatable": "yes"
+    },
+    "stroke-width": {
+      "name": "stroke-width",
+      "value": "<length-percentage>",
+      "initial": "1",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "stroke-linecap": {
+      "name": "stroke-linecap",
+      "value": "butt | round | square",
+      "initial": "butt",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "stroke-linejoin": {
+      "name": "stroke-linejoin",
+      "value": "miter | miter-clip | round | bevel | arcs",
+      "initial": "miter",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "stroke-miterlimit": {
+      "name": "stroke-miterlimit",
+      "value": "<number>",
+      "initial": "4",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "stroke-dasharray": {
+      "name": "stroke-dasharray",
+      "value": "none | <dasharray>",
+      "initial": "none",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute lengths or percentages for <dasharray>, or keyword specified",
+      "animatable": "yes (non-additive)"
+    },
+    "stroke-dashoffset": {
+      "name": "stroke-dashoffset",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "marker-start": {
+      "name": "marker-start",
+      "value": "none | <marker-ref>",
+      "initial": "none",
+      "appliesTo": "shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker-mid": {
+      "name": "marker-mid",
+      "value": "none | <marker-ref>",
+      "initial": "none",
+      "appliesTo": "shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker-end": {
+      "name": "marker-end",
+      "value": "none | <marker-ref>",
+      "initial": "none",
+      "appliesTo": "shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker": {
+      "name": "marker",
+      "value": "none | <marker-ref>",
+      "initial": "not defined for shorthand properties",
+      "appliesTo": "shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties",
+      "animatable": "yes"
+    },
+    "paint-order": {
+      "name": "paint-order",
+      "value": "normal | [ fill || stroke || markers ]",
+      "initial": "normal",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "color-interpolation": {
+      "name": "color-interpolation",
+      "value": "auto | sRGB | linearRGB",
+      "initial": "sRGB",
+      "appliesTo": "container elements, graphics elements, gradient elements, ‘use’ and ‘animate’",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "color-rendering": {
+      "name": "color-rendering",
+      "value": "auto | optimizeSpeed | optimizeQuality",
+      "initial": "auto",
+      "appliesTo": "container elements, graphics elements, gradient elements, ‘use’ and ‘animate’",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "shape-rendering": {
+      "name": "shape-rendering",
+      "value": "auto | optimizeSpeed | crispEdges | geometricPrecision",
+      "initial": "auto",
+      "appliesTo": "shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "text-rendering": {
+      "name": "text-rendering",
+      "value": "auto | optimizeSpeed | optimizeLegibility | geometricPrecision",
+      "initial": "auto",
+      "appliesTo": "‘text’",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "image-rendering": {
+      "name": "image-rendering",
+      "value": "auto | optimizeQuality | optimizeSpeed",
+      "initial": "auto",
+      "appliesTo": "images",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "pointer-events": {
+      "name": "pointer-events",
+      "value": "bounding-box | visiblePainted | visibleFill | visibleStroke | visible | painted | fill | stroke | all | none",
+      "initial": "visiblePainted",
+      "appliesTo": "container elements, graphics elements and ‘use’",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<points>": {
+      "value": "[ <number>+ ]#"
+    },
+    "<dasharray>": {
+      "value": "[ <length-percentage> | <number> ]#*"
+    },
+    "<marker-ref>": {
+      "value": "<url>"
+    }
+  }
+}
diff --git a/w3c/css/compat.json b/w3c/css/compat.json
new file mode 100644
index 000000000000..3b26b09d34d6
--- /dev/null
+++ b/w3c/css/compat.json
@@ -0,0 +1,91 @@
+{
+  "properties": {
+    "-webkit-background-clip": {
+      "name": "-webkit-background-clip",
+      "value": "border-box | padding-box | content-box | text",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "\"text\"",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "-webkit-text-fill-color": {
+      "name": "-webkit-text-fill-color",
+      "value": "<color>",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "an RGBA color",
+      "canonicalOrder": "per grammar",
+      "animationType": "as color"
+    },
+    "-webkit-text-stroke-color": {
+      "name": "-webkit-text-stroke-color",
+      "value": "<color>",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "an RGBA color",
+      "canonicalOrder": "per grammar",
+      "animationType": "as color"
+    },
+    "-webkit-text-stroke-width": {
+      "name": "-webkit-text-stroke-width",
+      "value": "<line-width>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "-webkit-text-stroke": {
+      "name": "-webkit-text-stroke",
+      "value": "<line-width> || <color>",
+      "initial": "See individual properties",
+      "appliesTo": "See individual properties",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "See individual properties",
+      "canonicalOrder": "per grammar",
+      "animationType": "See individual properties"
+    },
+    "touch-action": {
+      "name": "touch-action",
+      "value": "auto | none | [ [ pan-x | pan-left | pan-right ] || [ pan-y | pan-up | pan-down ] || pinch-zoom ] | manipulation",
+      "initial": "auto",
+      "appliesTo": "all elements except: non-replaced inline elements, table rows, row groups, table columns, and column groups.",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "Same as specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {
+    "-webkit-device-pixel-ratio": {
+      "name": "-webkit-device-pixel-ratio",
+      "for": "@media",
+      "value": "<number>",
+      "type": "range"
+    },
+    "-webkit-transform-3d": {
+      "name": "-webkit-transform-3d",
+      "for": "@media",
+      "value": "<mq-boolean>",
+      "acceptsMin/maxPrefixes": "no"
+    }
+  },
+  "valuespaces": {}
+}
diff --git a/w3c/css/compositing.json b/w3c/css/compositing.json
new file mode 100644
index 000000000000..ba22133d8dc1
--- /dev/null
+++ b/w3c/css/compositing.json
@@ -0,0 +1,52 @@
+{
+  "properties": {
+    "mix-blend-mode": {
+      "name": "mix-blend-mode",
+      "value": "<blend-mode>",
+      "initial": "normal",
+      "appliesTo": "All elements. In SVG, it applies to container elements, graphics elements and graphics referencing elements. [SVG11]",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "isolation": {
+      "name": "isolation",
+      "value": "<isolation-mode>",
+      "initial": "auto",
+      "appliesTo": "All elements. In SVG, it applies to container elements, graphics elements and graphics referencing elements. [SVG11]",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "background-blend-mode": {
+      "name": "background-blend-mode",
+      "value": "<blend-mode>#",
+      "initial": "normal",
+      "appliesTo": "All HTML elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<blend-mode>": {
+      "value": "normal | multiply | screen | overlay | darken | lighten | color-dodge |color-burn | hard-light | soft-light | difference | exclusion | hue | saturation | color | luminosity"
+    },
+    "<isolation-mode>": {
+      "value": "auto | isolate"
+    },
+    "<composite-mode>": {
+      "value": "clear | copy | source-over | destination-over | source-in | destination-in | source-out | destination-out | source-atop | destination-atop | xor | lighter | plus-darker | plus-lighter"
+    }
+  }
+}
diff --git a/w3c/css/css-align.json b/w3c/css/css-align.json
new file mode 100644
index 000000000000..1f615ddf3dff
--- /dev/null
+++ b/w3c/css/css-align.json
@@ -0,0 +1,154 @@
+{
+  "properties": {
+    "align-content": {
+      "name": "align-content",
+      "value": "normal | <baseline-position> | <content-distribution> | <overflow-position>? <content-position>",
+      "initial": "normal",
+      "appliesTo": "block containers, multicol containers, flex containers, and grid containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "justify-content": {
+      "name": "justify-content",
+      "value": "normal | <content-distribution> | <overflow-position>? [ <content-position> | left | right ]",
+      "initial": "normal",
+      "appliesTo": "multicol containers, flex containers, and grid containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "place-content": {
+      "name": "place-content",
+      "value": "<‘align-content’> <‘justify-content’>?",
+      "initial": "normal",
+      "appliesTo": "block containers, flex containers, and grid containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "justify-self": {
+      "name": "justify-self",
+      "value": "auto | normal | stretch | <baseline-position> | <overflow-position>? [ <self-position> | left | right ]",
+      "initial": "auto",
+      "appliesTo": "block-level boxes, absolutely-positioned boxes, and grid items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "align-self": {
+      "name": "align-self",
+      "value": "auto | normal | stretch | <baseline-position> | <overflow-position>? <self-position>",
+      "initial": "auto",
+      "appliesTo": "flex items, grid items, and absolutely-positioned boxes",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "place-self": {
+      "name": "place-self",
+      "value": "<‘align-self’> <‘justify-self’>?",
+      "initial": "auto",
+      "appliesTo": "block-level boxes, absolutely-positioned boxes, and grid items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "justify-items": {
+      "name": "justify-items",
+      "value": "normal | stretch | <baseline-position> | <overflow-position>? [ <self-position> | left | right ] | legacy | legacy && [ left | right | center ]",
+      "initial": "legacy",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value, except for legacy (see prose)",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "align-items": {
+      "name": "align-items",
+      "value": "normal | stretch | <baseline-position> | [ <overflow-position>? <self-position> ]",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "place-items": {
+      "name": "place-items",
+      "value": "<‘align-items’> <‘justify-items’>?",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "row-gap": {
+      "name": "row-gap",
+      "value": "normal | <length-percentage>",
+      "initial": "normal",
+      "appliesTo": "multi-column containers, flex containers, grid containers",
+      "inherited": "no",
+      "percentages": "refer to corresponding dimension of the content area",
+      "computedValue": "as specified, with <length>s made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "column-gap": {
+      "name": "column-gap",
+      "value": "normal | <length-percentage>",
+      "initial": "normal",
+      "appliesTo": "multi-column containers, flex containers, grid containers",
+      "inherited": "no",
+      "percentages": "refer to corresponding dimension of the content area",
+      "computedValue": "as specified, with <length>s made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "gap": {
+      "name": "gap",
+      "value": "<‘row-gap’> <‘column-gap’>?",
+      "initial": "see individual properties",
+      "appliesTo": "multi-column containers, flex containers, grid containers",
+      "inherited": "no",
+      "percentages": "refer to corresponding dimension of the content area",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<self-position>": {
+      "value": "center | start | end | self-start | self-end | flex-start | flex-end;"
+    },
+    "<content-position>": {
+      "value": "center | start | end | flex-start | flex-end;"
+    },
+    "<baseline-position>": {
+      "value": "[ first | last ]? baseline"
+    },
+    "<content-distribution>": {
+      "value": "space-between | space-around | space-evenly | stretch"
+    },
+    "<overflow-position>": {
+      "value": "unsafe | safe"
+    }
+  }
+}
diff --git a/w3c/css/css-animations.json b/w3c/css/css-animations.json
new file mode 100644
index 000000000000..4835c287d25f
--- /dev/null
+++ b/w3c/css/css-animations.json
@@ -0,0 +1,21 @@
+{
+  "properties": {
+    "animation-composition": {
+      "name": "animation-composition",
+      "value": "<single-animation-composition>#",
+      "initial": "replace",
+      "appliesTo": "all elements, ::before and ::after pseudo-elements",
+      "inherited": "none",
+      "percentages": "N/A",
+      "computedValue": "As specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<single-animation-composition>": {
+      "value": "replace | add | accumulate"
+    }
+  }
+}
diff --git a/w3c/css/css-backgrounds.json b/w3c/css/css-backgrounds.json
new file mode 100644
index 000000000000..dfc18a193173
--- /dev/null
+++ b/w3c/css/css-backgrounds.json
@@ -0,0 +1,233 @@
+{
+  "properties": {
+    "background-position": {
+      "name": "background-position",
+      "value": "<position>#",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "background-position-x": {
+      "name": "background-position-x",
+      "value": "[ center | [ left | right | x-start | x-end ]? <length-percentage>? ]#",
+      "initial": "left",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to width of background positioning area minus width of background image",
+      "computedValue": "A list, each item consisting of: an offset given as a combination of an absolute length and a percentage, plus an origin keyword",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "background-position-y": {
+      "name": "background-position-y",
+      "value": "[ center | [ top | bottom | y-start | y-end ]? <length-percentage>? ]#",
+      "initial": "left",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to height of background positioning area minus height of background image",
+      "computedValue": "A list, each item consisting of: an offset given as a combination of an absolute length and a percentage, plus an origin keyword",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "background-position-inline": {
+      "name": "background-position-inline",
+      "value": "[ center | [ start | end ]? <length-percentage>? ]#",
+      "initial": "not applicable (initial value comes from physical property)",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to inline-size of background positioning area minus inline-size of background image",
+      "computedValue": "A list, each item consisting of: an offset given as a combination of an absolute length and a percentage, plus an origin keyword",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "background-position-block": {
+      "name": "background-position-block",
+      "value": "[ center | [ start | end ]? <length-percentage>? ]#",
+      "initial": "not applicable (initial value comes from physical property)",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to size of background positioning area minus size of background image",
+      "computedValue": "A list, each item consisting of: an offset given as a combination of an absolute length and a percentage, plus an origin keyword",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "background-clip": {
+      "name": "background-clip",
+      "value": "<bg-clip>#",
+      "initial": "border-box",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-top-color": {
+      "name": "border-top-color",
+      "value": "<color>#",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "the computed color",
+      "canonicalOrder": "per grammar",
+      "animationType": "see prose"
+    },
+    "border-right-color": {
+      "name": "border-right-color",
+      "value": "<color>#",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "the computed color",
+      "canonicalOrder": "per grammar",
+      "animationType": "see prose"
+    },
+    "border-bottom-color": {
+      "name": "border-bottom-color",
+      "value": "<color>#",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "the computed color",
+      "canonicalOrder": "per grammar",
+      "animationType": "see prose"
+    },
+    "border-left-color": {
+      "name": "border-left-color",
+      "value": "<color>#",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "the computed color",
+      "canonicalOrder": "per grammar",
+      "animationType": "see prose"
+    },
+    "border-color": {
+      "name": "border-color",
+      "value": "<color>{1,4}#",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-radius": {
+      "name": "border-radius",
+      "value": "<length-percentage>{1,4} [ / <length-percentage>{1,4} ]?",
+      "initial": "0",
+      "appliesTo": "all elements, except table element when border-collapse is collapse",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "corner-shape": {
+      "name": "corner-shape",
+      "value": "[ round | bevel | scoop | notch ]{1,4}",
+      "initial": "round",
+      "appliesTo": "all elements, except table element when border-collapse is collapse",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "corners": {
+      "name": "corners",
+      "value": "<‘corner-shape’> || <‘border-radius’>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-limit": {
+      "name": "border-limit",
+      "value": "all | [ sides | corners ] <length-percentage>? | [ top | right | bottom | left ] <length-percentage>",
+      "initial": "round",
+      "appliesTo": "all elements, except table element when border-collapse is collapse",
+      "inherited": "no",
+      "percentages": "relative to border-box",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-clip": {
+      "name": "border-clip",
+      "value": "normal | [ <length-percentage> | <flex> ]+",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to length of border-edge side",
+      "computedValue": "normal, or a list consisting of absolute lengths, or percentages as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-clip-top": {
+      "name": "border-clip-top",
+      "value": "normal | [ <length-percentage> | <flex> ]+",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to length of border-edge side",
+      "computedValue": "normal, or a list consisting of absolute lengths, or percentages as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-clip-right": {
+      "name": "border-clip-right",
+      "value": "normal | [ <length-percentage> | <flex> ]+",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to length of border-edge side",
+      "computedValue": "normal, or a list consisting of absolute lengths, or percentages as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-clip-bottom": {
+      "name": "border-clip-bottom",
+      "value": "normal | [ <length-percentage> | <flex> ]+",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to length of border-edge side",
+      "computedValue": "normal, or a list consisting of absolute lengths, or percentages as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-clip-left": {
+      "name": "border-clip-left",
+      "value": "normal | [ <length-percentage> | <flex> ]+",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to length of border-edge side",
+      "computedValue": "normal, or a list consisting of absolute lengths, or percentages as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<position>": {
+      "value": "[ [ left | center | right | top | bottom | start | end | <length-percentage> ] | [ left | center | right | x-start | x-end | <length-percentage> ] [ top | center | bottom | y-start | y-end | <length-percentage> ] | [ center | [ left | right | x-start | x-end ] <length-percentage>? ] && [ center | [ top | bottom | y-start | y-end ] <length-percentage>? ] | [ center | [ start | end ] <length-percentage>? ] [ center | [ start | end ] <length-percentage>? ] ]"
+    },
+    "<bg-clip>": {
+      "value": "<box> | border | text"
+    }
+  }
+}
diff --git a/w3c/css/css-box.json b/w3c/css/css-box.json
new file mode 100644
index 000000000000..032c3e09cb4d
--- /dev/null
+++ b/w3c/css/css-box.json
@@ -0,0 +1,116 @@
+{
+  "properties": {
+    "margin-top": {
+      "name": "margin-top",
+      "value": "<length-percentage> | auto",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "margin-right": {
+      "name": "margin-right",
+      "value": "<length-percentage> | auto",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "margin-bottom": {
+      "name": "margin-bottom",
+      "value": "<length-percentage> | auto",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "margin-left": {
+      "name": "margin-left",
+      "value": "<length-percentage> | auto",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "margin": {
+      "name": "margin",
+      "value": "<‘margin-top’>{1,4}",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "padding-top": {
+      "name": "padding-top",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "padding-right": {
+      "name": "padding-right",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "padding-bottom": {
+      "name": "padding-bottom",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "padding-left": {
+      "name": "padding-left",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "padding": {
+      "name": "padding",
+      "value": "<‘padding-top’>{1,4}",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-break.json b/w3c/css/css-break.json
new file mode 100644
index 000000000000..620694d28043
--- /dev/null
+++ b/w3c/css/css-break.json
@@ -0,0 +1,72 @@
+{
+  "properties": {
+    "break-before": {
+      "name": "break-before",
+      "value": "auto | avoid | avoid-page | page | left | right | recto | verso | avoid-column | column | avoid-region | region",
+      "initial": "auto",
+      "appliesTo": "block-level elements, table row groups, table rows (but see prose)",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "break-after": {
+      "name": "break-after",
+      "value": "auto | avoid | avoid-page | page | left | right | recto | verso | avoid-column | column | avoid-region | region",
+      "initial": "auto",
+      "appliesTo": "block-level elements, table row groups, table rows (but see prose)",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "break-inside": {
+      "name": "break-inside",
+      "value": "auto | avoid | avoid-page | avoid-column | avoid-region",
+      "initial": "auto",
+      "appliesTo": "elements in the normal flow that establish formatting contexts, or that are block containers, table row groups, or table rows",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "orphans": {
+      "name": "orphans",
+      "value": "<integer>",
+      "initial": "2",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "widows": {
+      "name": "widows",
+      "value": "<integer>",
+      "initial": "2",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "box-decoration-break": {
+      "name": "box-decoration-break",
+      "value": "slice | clone",
+      "initial": "slice",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-cascade.json b/w3c/css/css-cascade.json
new file mode 100644
index 000000000000..fec8cb9a4670
--- /dev/null
+++ b/w3c/css/css-cascade.json
@@ -0,0 +1,16 @@
+{
+  "properties": {
+    "all": {
+      "name": "all",
+      "value": "initial | inherit | unset | revert",
+      "initial": "See individual properties",
+      "appliesTo": "See individual properties",
+      "inherited": "See individual properties",
+      "percentages": "See individual properties",
+      "computedValue": "See individual properties",
+      "animatable": "See individual properties"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-color.json b/w3c/css/css-color.json
new file mode 100644
index 000000000000..8f7cf27bad92
--- /dev/null
+++ b/w3c/css/css-color.json
@@ -0,0 +1,89 @@
+{
+  "properties": {
+    "color": {
+      "name": "color",
+      "value": "<color>",
+      "initial": "UA-defined, see prose",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "See resolving color values",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "opacity": {
+      "name": "opacity",
+      "value": "<alpha-value>",
+      "initial": "1",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "the specified value converted to a number, clamped to the range [0,1]",
+      "canonicalOrder": "per grammar",
+      "animationType": "as number"
+    },
+    "color-adjust": {
+      "name": "color-adjust",
+      "value": "economy | exact",
+      "initial": "economy",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {
+    "src": {
+      "name": "src",
+      "for": "@color-profile",
+      "value": "<url>",
+      "initial": "n/a"
+    },
+    "rendering-intent": {
+      "name": "rendering-intent",
+      "for": "@color-profile",
+      "value": "relative-colorimetric | absolute-colorimetric | perceptual | saturation",
+      "initial": "relative-colorimetric"
+    }
+  },
+  "valuespaces": {
+    "<color>": {
+      "value": "<rgb()> | <rgba()> | <hsl()> | <hsla()> | <hwb()> | <gray()> | <device-cmyk()> | <hex-color> | <named-color> | currentcolor | <deprecated-system-color>"
+    },
+    "<rgb()>": {
+      "value": "rgb( <percentage>{3} [ / <alpha-value> ]? ) | rgb( <number>{3} [ / <alpha-value> ]? )"
+    },
+    "<alpha-value>": {
+      "value": "<number> | <percentage>"
+    },
+    "<hsl()>": {
+      "value": "hsl( <hue> <percentage> <percentage> [ / <alpha-value> ]? )"
+    },
+    "<hue>": {
+      "value": "<number> | <angle>"
+    },
+    "<hwb()>": {
+      "value": "hwb( <hue> <percentage> <percentage> [ / <alpha-value> ]? )"
+    },
+    "<lab()>": {
+      "value": "lab( <number> <number> <number> [ / <alpha-value> ]? )"
+    },
+    "<lch()>": {
+      "value": "lch( <number> <number> <hue> [ / <alpha-value> ]? )"
+    },
+    "<gray()>": {
+      "value": "gray( <number> [ / <alpha-value> ]? )"
+    },
+    "<color()>": {
+      "value": "color( [ <ident>? [ <number>+ | <string> ] [ / <alpha-value> ]? ]# , <color>? )"
+    },
+    "<device-cmyk()>": {
+      "value": "device-cmyk( <cmyk-component>{4} [ / <alpha-value> ]? , <color>? )"
+    },
+    "<cmyk-component>": {
+      "value": "<number> | <percentage>"
+    }
+  }
+}
diff --git a/w3c/css/css-conditional.json b/w3c/css/css-conditional.json
new file mode 100644
index 000000000000..f47bdfe0b5f7
--- /dev/null
+++ b/w3c/css/css-conditional.json
@@ -0,0 +1,18 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<supports-condition>": {
+      "value": "not <supports-in-parens> | <supports-in-parens> [ and <supports-in-parens> ]* | <supports-in-parens> [ or <supports-in-parens> ]*"
+    },
+    "<supports-in-parens>": {
+      "value": "( <supports-condition> ) | <supports-feature> | <general-enclosed>"
+    },
+    "<supports-feature>": {
+      "value": "<supports-decl>"
+    },
+    "<supports-decl>": {
+      "value": "( <declaration> )"
+    }
+  }
+}
diff --git a/w3c/css/css-contain.json b/w3c/css/css-contain.json
new file mode 100644
index 000000000000..b9273eb72232
--- /dev/null
+++ b/w3c/css/css-contain.json
@@ -0,0 +1,17 @@
+{
+  "properties": {
+    "contain": {
+      "name": "contain",
+      "value": "none | strict | content | [ size || layout || style || paint ]",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "not animatable"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-content.json b/w3c/css/css-content.json
new file mode 100644
index 000000000000..2acc1e10a90f
--- /dev/null
+++ b/w3c/css/css-content.json
@@ -0,0 +1,106 @@
+{
+  "properties": {
+    "content": {
+      "name": "content",
+      "value": "normal | none | [ <content-replacement> | <content-list> ] [/ <string> ]?",
+      "initial": "normal",
+      "appliesTo": "all elements, tree-abiding pseudo-elements, and page margin boxes",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "As specified below",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "quotes": {
+      "name": "quotes",
+      "value": "none | [ <string> <string> ]+",
+      "initial": "depends on user agent",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "string-set": {
+      "name": "string-set",
+      "value": "none | [ <custom-ident> <string>+ ]#",
+      "initial": "none",
+      "appliesTo": "all elements, but not pseudo-elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "bookmark-level": {
+      "name": "bookmark-level",
+      "value": "none | <integer>",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "bookmark-label": {
+      "name": "bookmark-label",
+      "value": "<content-list>",
+      "initial": "content(text)",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "bookmark-state": {
+      "name": "bookmark-state",
+      "value": "open | closed",
+      "initial": "open",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<quote>": {
+      "value": "open-quote | close-quote | no-open-quote | no-close-quote"
+    },
+    "<leader()>": {
+      "value": "leader( <leader-type> )"
+    },
+    "<leader-type>": {
+      "value": "dotted | solid | space | <string>"
+    },
+    "<target>": {
+      "value": "<target-counter()> | <target-counters()> | <target-text()>"
+    },
+    "<target-counter()>": {
+      "value": "target-counter( [ <string> | <url> ] , <custom-ident> , <counter-style>? )"
+    },
+    "<target-counters()>": {
+      "value": "target-counters( [ <string> | <url> ] , <custom-ident> , <string> , <counter-style>? )"
+    },
+    "<target-text()>": {
+      "value": "target-text( [ <string> | <url> ] , [ content | before | after | first-letter ]? )"
+    },
+    "<string()>": {
+      "value": "string( <custom-ident> , [ first | start | last | first-except ]? )"
+    },
+    "<content()>": {
+      "value": "content( [ text | before | after | first-letter | marker ]? )"
+    },
+    "<content-replacement>": {
+      "value": "<image>"
+    },
+    "<content-list>": {
+      "value": "[ <string> | contents | <image> | <quote> | <target> | <leader()> ]+"
+    }
+  }
+}
diff --git a/w3c/css/css-counter-styles.json b/w3c/css/css-counter-styles.json
new file mode 100644
index 000000000000..0f7dfeef2c13
--- /dev/null
+++ b/w3c/css/css-counter-styles.json
@@ -0,0 +1,79 @@
+{
+  "properties": {},
+  "descriptors": {
+    "system": {
+      "name": "system",
+      "for": "@counter-style",
+      "value": "cyclic | numeric | alphabetic | symbolic | additive | [fixed <integer>?] | [ extends <counter-style-name> ]",
+      "initial": "symbolic"
+    },
+    "negative": {
+      "name": "negative",
+      "for": "@counter-style",
+      "value": "<symbol> <symbol>?",
+      "initial": "\"\\2D\" (\"-\" hyphen-minus)"
+    },
+    "prefix": {
+      "name": "prefix",
+      "for": "@counter-style",
+      "value": "<symbol>",
+      "initial": "\"\" (the empty string)"
+    },
+    "suffix": {
+      "name": "suffix",
+      "for": "@counter-style",
+      "value": "<symbol>",
+      "initial": "\"\\2E\\20\" (\".\" full stop followed by a space)"
+    },
+    "range": {
+      "name": "range",
+      "for": "@counter-style",
+      "value": "[ [ <integer> | infinite ]{2} ]# | auto",
+      "initial": "auto"
+    },
+    "pad": {
+      "name": "pad",
+      "for": "@counter-style",
+      "value": "<integer> && <symbol>",
+      "initial": "0 \"\""
+    },
+    "fallback": {
+      "name": "fallback",
+      "for": "@counter-style",
+      "value": "<counter-style-name>",
+      "initial": "decimal"
+    },
+    "symbols": {
+      "name": "symbols",
+      "for": "@counter-style",
+      "value": "<symbol>+",
+      "initial": "n/a"
+    },
+    "additive-symbols": {
+      "name": "additive-symbols",
+      "for": "@counter-style",
+      "value": "[ <integer> && <symbol> ]#",
+      "initial": "n/a"
+    },
+    "speak-as": {
+      "name": "speak-as",
+      "for": "@counter-style",
+      "value": "auto | bullets | numbers | words | spell-out | <counter-style-name>",
+      "initial": "auto"
+    }
+  },
+  "valuespaces": {
+    "<symbol>": {
+      "value": "<string> | <image> | <custom-ident>"
+    },
+    "<symbols()>": {
+      "value": "symbols( <symbols-type>? [ <string> | <image> ]+ );"
+    },
+    "<symbols-type>": {
+      "value": "cyclic | numeric | alphabetic | symbolic | fixed;"
+    },
+    "<counter-style>": {
+      "value": "<counter-style-name> | symbols();"
+    }
+  }
+}
diff --git a/w3c/css/css-device-adapt.json b/w3c/css/css-device-adapt.json
new file mode 100644
index 000000000000..92a904925734
--- /dev/null
+++ b/w3c/css/css-device-adapt.json
@@ -0,0 +1,98 @@
+{
+  "properties": {},
+  "descriptors": {
+    "min-width": {
+      "name": "min-width",
+      "for": "@viewport",
+      "value": "<viewport-length>",
+      "initial": "auto",
+      "percentages": "Refer to the width of the initial viewport",
+      "computedValue": "auto, an absolute length, or a percentage as specified"
+    },
+    "max-width": {
+      "name": "max-width",
+      "for": "@viewport",
+      "value": "<viewport-length>",
+      "initial": "auto",
+      "percentages": "Refer to the width of the initial viewport",
+      "computedValue": "auto, an absolute length, or a percentage as specified"
+    },
+    "width": {
+      "name": "width",
+      "for": "@viewport",
+      "value": "<viewport-length>{1,2}",
+      "initial": "See individual descriptors",
+      "percentages": "See individual descriptors",
+      "computedValue": "See individual descriptors"
+    },
+    "min-height": {
+      "name": "min-height",
+      "for": "@viewport",
+      "value": "<viewport-length>",
+      "initial": "auto",
+      "percentages": "Refer to the height of the initial viewport",
+      "computedValue": "auto, an absolute length, or a percentage as specified"
+    },
+    "max-height": {
+      "name": "max-height",
+      "for": "@viewport",
+      "value": "<viewport-length>",
+      "initial": "auto",
+      "percentages": "Refer to the height of the initial viewport",
+      "computedValue": "auto, an absolute length, or a percentage as specified"
+    },
+    "height": {
+      "name": "height",
+      "for": "@viewport",
+      "value": "<viewport-length>{1,2}",
+      "initial": "See individual descriptors",
+      "percentages": "See individual descriptors",
+      "computedValue": "See individual descriptors"
+    },
+    "zoom": {
+      "name": "zoom",
+      "for": "@viewport",
+      "value": "auto | <number> | <percentage>",
+      "initial": "auto",
+      "percentages": "The zoom factor itself",
+      "computedValue": "auto, or a non-negative number or percentage as specified"
+    },
+    "min-zoom": {
+      "name": "min-zoom",
+      "for": "@viewport",
+      "value": "auto | <number> | <percentage>",
+      "initial": "auto",
+      "percentages": "The zoom factor itself",
+      "computedValue": "auto, or a non-negative number or percentage as specified"
+    },
+    "max-zoom": {
+      "name": "max-zoom",
+      "for": "@viewport",
+      "value": "auto | <number> | <percentage>",
+      "initial": "auto",
+      "percentages": "The zoom factor itself",
+      "computedValue": "auto, or a non-negative number or percentage as specified"
+    },
+    "user-zoom": {
+      "name": "user-zoom",
+      "for": "@viewport",
+      "value": "zoom | fixed",
+      "initial": "zoom",
+      "percentages": "N/A",
+      "computedValue": "as specified"
+    },
+    "orientation": {
+      "name": "orientation",
+      "for": "@viewport",
+      "value": "auto | portrait | landscape",
+      "initial": "auto",
+      "percentages": "N/A",
+      "computedValue": "as specified"
+    }
+  },
+  "valuespaces": {
+    "<viewport-length>": {
+      "value": "auto | <length> | <percentage>"
+    }
+  }
+}
diff --git a/w3c/css/css-display.json b/w3c/css/css-display.json
new file mode 100644
index 000000000000..c5124130cadf
--- /dev/null
+++ b/w3c/css/css-display.json
@@ -0,0 +1,36 @@
+{
+  "properties": {
+    "display": {
+      "name": "display",
+      "value": "[ <display-outside> || <display-inside> ] | <display-listitem> | <display-internal> | <display-box> | <display-legacy>",
+      "initial": "inline",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "see prose in a variety of specs",
+      "canonicalOrder": "per grammar",
+      "animationType": "not animatable"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<display-outside>": {
+      "value": "block | inline | run-in ;"
+    },
+    "<display-inside>": {
+      "value": "flow | flow-root | table | flex | grid | ruby ;"
+    },
+    "<display-listitem>": {
+      "value": "<display-outside>? && [ flow | flow-root ]? && list-item ;"
+    },
+    "<display-internal>": {
+      "value": "table-row-group | table-header-group | table-footer-group | table-row | table-cell | table-column-group | table-column | table-caption | ruby-base | ruby-text | ruby-base-container | ruby-text-container ;"
+    },
+    "<display-box>": {
+      "value": "contents | none ;"
+    },
+    "<display-legacy>": {
+      "value": "inline-block | inline-table | inline-flex | inline-grid ;"
+    }
+  }
+}
diff --git a/w3c/css/css-env.json b/w3c/css/css-env.json
new file mode 100644
index 000000000000..23118de93c61
--- /dev/null
+++ b/w3c/css/css-env.json
@@ -0,0 +1,9 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<env()>": {
+      "value": "env( <custom-ident> , <declaration-value>? )"
+    }
+  }
+}
diff --git a/w3c/css/css-exclusions.json b/w3c/css/css-exclusions.json
new file mode 100644
index 000000000000..47be99b709f6
--- /dev/null
+++ b/w3c/css/css-exclusions.json
@@ -0,0 +1,28 @@
+{
+  "properties": {
+    "wrap-flow": {
+      "name": "wrap-flow",
+      "value": "auto | both | start | end | minimum | maximum | clear",
+      "initial": "auto",
+      "appliesTo": "block-level elements.",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified except for element’s whose float computed value is not none, in which case the computed value is auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "wrap-through": {
+      "name": "wrap-through",
+      "value": "wrap | none",
+      "initial": "wrap",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-flexbox.json b/w3c/css/css-flexbox.json
new file mode 100644
index 000000000000..ffb575044f99
--- /dev/null
+++ b/w3c/css/css-flexbox.json
@@ -0,0 +1,142 @@
+{
+  "properties": {
+    "display": {
+      "name": "display",
+      "newValues": "flex | inline-flex"
+    },
+    "flex-direction": {
+      "name": "flex-direction",
+      "value": "row | row-reverse | column | column-reverse",
+      "initial": "row",
+      "appliesTo": "flex containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "flex-wrap": {
+      "name": "flex-wrap",
+      "value": "nowrap | wrap | wrap-reverse",
+      "initial": "nowrap",
+      "appliesTo": "flex containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "flex-flow": {
+      "name": "flex-flow",
+      "value": "<‘flex-direction’> || <‘flex-wrap’>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "order": {
+      "name": "order",
+      "value": "<integer>",
+      "initial": "0",
+      "appliesTo": "flex items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "integer"
+    },
+    "flex": {
+      "name": "flex",
+      "value": "none | [ <‘flex-grow’> <‘flex-shrink’>? || <‘flex-basis’> ]",
+      "initial": "0 1 auto",
+      "appliesTo": "flex items",
+      "inherited": "no",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "flex-grow": {
+      "name": "flex-grow",
+      "value": "<number>",
+      "initial": "0",
+      "appliesTo": "flex items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "number"
+    },
+    "flex-shrink": {
+      "name": "flex-shrink",
+      "value": "<number>",
+      "initial": "1",
+      "appliesTo": "flex items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "number"
+    },
+    "flex-basis": {
+      "name": "flex-basis",
+      "value": "content | <‘width’>",
+      "initial": "auto",
+      "appliesTo": "flex items",
+      "inherited": "no",
+      "percentages": "relative to the flex container’s inner main size",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete for keywords, otherwise as length, percentage, or calc"
+    },
+    "justify-content": {
+      "name": "justify-content",
+      "value": "flex-start | flex-end | center | space-between | space-around",
+      "initial": "flex-start",
+      "appliesTo": "flex containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "align-items": {
+      "name": "align-items",
+      "value": "flex-start | flex-end | center | baseline | stretch",
+      "initial": "stretch",
+      "appliesTo": "flex containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "align-self": {
+      "name": "align-self",
+      "value": "auto | flex-start | flex-end | center | baseline | stretch",
+      "initial": "auto",
+      "appliesTo": "flex items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "align-content": {
+      "name": "align-content",
+      "value": "flex-start | flex-end | center | space-between | space-around | stretch",
+      "initial": "stretch",
+      "appliesTo": "multi-line flex containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-fonts.json b/w3c/css/css-fonts.json
new file mode 100644
index 000000000000..3ded8263541c
--- /dev/null
+++ b/w3c/css/css-fonts.json
@@ -0,0 +1,361 @@
+{
+  "properties": {
+    "font-family": {
+      "name": "font-family",
+      "value": "[ <family-name> | <generic-family> ] #",
+      "initial": "depends on user agent",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "a list of strings and/or <generic-family> keywords",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "font-weight": {
+      "name": "font-weight",
+      "value": "<font-weight-absolute> | bolder | lighter",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "numeric weight value (see description)",
+      "canonicalOrder": "per grammar",
+      "animatable": "As <number>"
+    },
+    "font-stretch": {
+      "name": "font-stretch",
+      "value": "normal | <percentage> | ultra-condensed | extra-condensed | condensed | semi-condensed | semi-expanded | expanded | extra-expanded | ultra-expanded",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "Not resolved",
+      "computedValue": "percentage",
+      "canonicalOrder": "per grammar",
+      "animatable": "As <percentage>"
+    },
+    "font-style": {
+      "name": "font-style",
+      "value": "normal | italic | oblique <angle>?",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "As specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "If both \"from\" and \"to\" values are \"oblique\", then yes, as an <angle>. Otherwise, no."
+    },
+    "font-size": {
+      "name": "font-size",
+      "value": "<absolute-size> | <relative-size> | <length-percentage>",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "refer to parent element’s font size",
+      "computedValue": "an absolute length, as clamped by font-min-size and font-max-size",
+      "canonicalOrder": "per grammar",
+      "animatable": "As <length>"
+    },
+    "font-min-size": {
+      "name": "font-min-size",
+      "value": "<absolute-size> | <relative-size> | <length-percentage>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "refer to parent element’s font size",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animatable": "As <length>"
+    },
+    "font-max-size": {
+      "name": "font-max-size",
+      "value": "<absolute-size> | <relative-size> | <length-percentage> | infinity",
+      "initial": "infinity",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "refer to parent element’s font size",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animatable": "As <length>"
+    },
+    "font-size-adjust": {
+      "name": "font-size-adjust",
+      "value": "none | <number>",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "as <number>"
+    },
+    "font": {
+      "name": "font",
+      "value": "[ [ <‘font-style’> || <font-variant-css2> || <‘font-weight’> || <font-stretch-css3> ]? <‘font-size’> [ / <‘line-height’> ]? <‘font-family’> ] | caption | icon | menu | message-box | small-caption | status-bar",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "see individual properties"
+    },
+    "font-synthesis-weight": {
+      "name": "font-synthesis-weight",
+      "value": "auto | none",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "yes"
+    },
+    "font-synthesis-style": {
+      "name": "font-synthesis-style",
+      "value": "auto | none",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "yes"
+    },
+    "font-synthesis-small-caps": {
+      "name": "font-synthesis-small-caps",
+      "value": "auto | none",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "yes"
+    },
+    "font-synthesis": {
+      "name": "font-synthesis",
+      "value": "none | [ weight || style ]",
+      "initial": "weight style small-caps",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "font-variant-alternates": {
+      "name": "font-variant-alternates",
+      "value": "normal | [ stylistic(<feature-value-name>) || historical-forms || styleset(<feature-value-name>#) || character-variant(<feature-value-name>#) || swash(<feature-value-name>) || ornaments(<feature-value-name>) || annotation(<feature-value-name>) ]",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "font-language-override": {
+      "name": "font-language-override",
+      "value": "normal | <string>",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "font-optical-sizing": {
+      "name": "font-optical-sizing",
+      "value": "auto | none",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "font-variation-settings": {
+      "name": "font-variation-settings",
+      "value": "normal | [ <string> <number>] #",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "yes (see description)"
+    },
+    "font-palette": {
+      "name": "font-palette",
+      "value": "normal | light | dark | <palette-identifier>",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/a",
+      "computedValue": "As specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "No (see below)"
+    },
+    "font-variant-emoji": {
+      "name": "font-variant-emoji",
+      "value": "auto | text | emoji",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/a",
+      "computedValue": "As specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "No (see below)"
+    }
+  },
+  "descriptors": {
+    "font-family": {
+      "name": "font-family",
+      "for": "@font-palette-values",
+      "value": "<‘font-family’>",
+      "initial": "N/A"
+    },
+    "src": {
+      "name": "src",
+      "for": "@font-face",
+      "value": "see prose",
+      "initial": "N/A"
+    },
+    "font-style": {
+      "name": "font-style",
+      "for": "@font-face",
+      "value": "auto | normal | italic | oblique [ <angle> | <angle> <angle> ] ?",
+      "initial": "normal"
+    },
+    "font-weight": {
+      "name": "font-weight",
+      "for": "@font-face",
+      "value": "auto | <font-weight-absolute> <font-weight-absolute>?",
+      "initial": "normal"
+    },
+    "font-stretch": {
+      "name": "font-stretch",
+      "for": "@font-face",
+      "value": "auto | <‘font-stretch’> <‘font-stretch’>?",
+      "initial": "normal"
+    },
+    "unicode-range": {
+      "name": "unicode-range",
+      "for": "@font-face",
+      "value": "<urange> #",
+      "initial": "U+0-10FFFF"
+    },
+    "font-variant": {
+      "name": "font-variant",
+      "for": "@font-face",
+      "value": "normal | none | [ <common-lig-values> || <discretionary-lig-values> || <historical-lig-values> || <contextual-alt-values> || stylistic(<feature-value-name>) || historical-forms || styleset(<feature-value-name>#) || character-variant(<feature-value-name>#) || swash(<feature-value-name>) || ornaments(<feature-value-name>) || annotation(<feature-value-name>) || [ small-caps | all-small-caps | petite-caps | all-petite-caps | unicase | titling-caps ] || <numeric-figure-values> || <numeric-spacing-values> || <numeric-fraction-values> || ordinal || slashed-zero || <east-asian-variant-values> || <east-asian-width-values> || ruby || [ sub | super ] ]",
+      "initial": "normal"
+    },
+    "font-feature-settings": {
+      "name": "font-feature-settings",
+      "for": "@font-face",
+      "value": "normal | <feature-tag-value> #",
+      "initial": "normal"
+    },
+    "font-variation-settings": {
+      "name": "font-variation-settings",
+      "for": "@font-face",
+      "value": "normal | [ <string> <number>] #",
+      "initial": "normal"
+    },
+    "font-named-instance": {
+      "name": "font-named-instance",
+      "for": "@font-face",
+      "value": "auto | <string>",
+      "initial": "auto"
+    },
+    "font-display": {
+      "name": "font-display",
+      "for": "@font-feature-values",
+      "value": "auto | block | swap | fallback | optional",
+      "initial": "auto"
+    },
+    "font-language-override": {
+      "name": "font-language-override",
+      "for": "@font-face",
+      "value": "normal | <string>",
+      "initial": "normal"
+    },
+    "base-palette": {
+      "name": "base-palette",
+      "for": "@font-palette-values",
+      "value": "<integer> | <string>",
+      "initial": "N/A"
+    },
+    "override-color": {
+      "name": "override-color",
+      "for": "@font-palette-values",
+      "value": "[ [ <string> | <integer> ] <color> ]#",
+      "initial": "N/A"
+    }
+  },
+  "valuespaces": {
+    "<font-weight-absolute>": {
+      "value": "[normal | bold | <number>]"
+    },
+    "<font-variant-css2>": {
+      "value": "[normal | small-caps]"
+    },
+    "<font-stretch-css3>": {
+      "value": "[normal | ultra-condensed | extra-condensed | condensed | semi-condensed | semi-expanded | expanded | extra-expanded | ultra-expanded]"
+    },
+    "<font-format>": {
+      "value": "[<string> | woff | truetype | opentype | woff2 | embedded-opentype | svg]"
+    },
+    "<font-technology>": {
+      "value": "[features | variations | color(<color-font-technology>) | palettes]"
+    },
+    "<color-font-technology>": {
+      "value": "[COLR | SVG | sbix]"
+    },
+    "<feature-value-name>": {
+      "value": "<ident>"
+    },
+    "<family-name>": {
+      "prose": "The name of a font family, such as Helvetica or Verdana in the previous example."
+    },
+    "<feature-value-block>": {
+      "value": "<feature-type> { <declaration-list> }"
+    },
+    "<feature-type>": {
+      "value": "@stylistic | @historical-forms | @styleset | @character-variant | @swash | @ornaments | @annotation"
+    },
+    "<feature-value>": {
+      "value": "<integer>+"
+    },
+    "<stylistic()>": {
+      "value": "stylistic(<feature-value-name>)"
+    },
+    "<styleset()>": {
+      "value": "styleset(<feature-value-name>#)"
+    },
+    "<character-variant()>": {
+      "value": "character-variant(<feature-value-name>#)"
+    },
+    "<swash()>": {
+      "value": "swash(<feature-value-name>)"
+    },
+    "<ornaments()>": {
+      "value": "ornaments(<feature-value-name>)"
+    },
+    "<annotation()>": {
+      "value": "annotation(<feature-value-name>)"
+    },
+    "<generic-family>": {
+      "prose": "Each <generic-family> keyword represents a generic font choice, and behaves as an alias for one or more locally-installed fonts belonging to the specified generic font category. A <generic-family> can thus be used as a reliable fallback for when an author’s more specific font choices are not available. Authors are encouraged to append a generic font family as a last alternative for improved robustness. Note that <generic-family> keywords cannot be quoted (otherwise they are interpreted as a <family-name>). The following generic family keywords are defined: serif, sans-serif, cursive, fantasy, monospace, system-ui, emoji, math and fangsong. See §2.1.3 Generic font families."
+    },
+    "<palette-identifier>": {
+      "prose": "This value identifies an author-define palette to use. Users can define a palette by using the @font-palette-values rule. If no applicable @font-palette-values rule is present, this value behaves as normal."
+    }
+  }
+}
diff --git a/w3c/css/css-gcpm.json b/w3c/css/css-gcpm.json
new file mode 100644
index 000000000000..cae16803d7bd
--- /dev/null
+++ b/w3c/css/css-gcpm.json
@@ -0,0 +1,17 @@
+{
+  "properties": {
+    "copy-into": {
+      "name": "copy-into",
+      "value": "none | [ [ <custom-ident> <content-level>] [, <custom-ident> <content-level>]* ]?",
+      "initial": "none",
+      "appliesTo": "all elements and pseudo-elements, but not ::first-line or ::first-letter.",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-grid.json b/w3c/css/css-grid.json
new file mode 100644
index 000000000000..d11c83b74982
--- /dev/null
+++ b/w3c/css/css-grid.json
@@ -0,0 +1,35 @@
+{
+  "properties": {
+    "grid-template-rows": {
+      "name": "grid-template-rows",
+      "newValues": "subgrid <line-name-list>?"
+    },
+    "grid-template-columns": {
+      "name": "grid-template-columns",
+      "newValues": "subgrid <line-name-list>?"
+    },
+    "align-content": {
+      "name": "align-content",
+      "newValues": "[ <aspect-ratio> <content-distribution>? ]"
+    },
+    "justify-content": {
+      "name": "justify-content",
+      "newValues": "[ <aspect-ratio> <content-distribution>? ]"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<line-name-list>": {
+      "value": "[ <line-names> | <name-repeat> ]+"
+    },
+    "<line-names>": {
+      "value": "'[' <custom-ident>* ']'"
+    },
+    "<name-repeat>": {
+      "value": "repeat( [ <positive-integer> | auto-fill ], <line-names>+)"
+    },
+    "<aspect-ratio>": {
+      "prose": "A dimension with the unit ar, representing a multiplier against the analogous quantity in the other dimension. If that quantity cannot be determined (e.g. is itself specified as a <aspect-ratio>, or otherwise can’t be referenced), then it is assumed to be zero. Note: This value can expand gutters even when there is no free space left, causing overflow. Specifically, an align-content value of 1ar represents the amount of space (which may be zero) allocated between two adjacent alignment subjects (grid tracks / flex lines / column boxes) by the justify-content property. Unless a different <content-distribution> value is specified, space is distributed according to the same <content-distribution> rules as for justify-content. The behavior of <number> values for justify-content is analogous. Note: The space allocated by align-content: 1ar will be zero if justify-content does not allocate space between adjacent alignment subjects: either due to not having a <content-distribution> value or due to there being fewer than two alignment subjects. If both align-content and justify-content have <number> values, then justify-content’s <number> value is ignored and its <content-distribution> value honored as if specified alone. fIf no <content-distribution> value was specified, then justify-content takes align-content’s <content-distribution> value (if one was specified) and otherwise falls back to space-between."
+    }
+  }
+}
diff --git a/w3c/css/css-images.json b/w3c/css/css-images.json
new file mode 100644
index 000000000000..d1447da6a7ca
--- /dev/null
+++ b/w3c/css/css-images.json
@@ -0,0 +1,81 @@
+{
+  "properties": {
+    "object-fit": {
+      "name": "object-fit",
+      "value": "fill | contain | cover | none | scale-down",
+      "initial": "fill",
+      "appliesTo": "replaced elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "object-position": {
+      "name": "object-position",
+      "value": "<position>",
+      "initial": "50% 50%",
+      "appliesTo": "replaced elements",
+      "inherited": "no",
+      "percentages": "refer to width and height of element itself",
+      "computedValue": "specified value",
+      "canonicalOrder": "the horizontal component of the <position>, followed by the vertical component",
+      "animatable": "yes"
+    },
+    "image-orientation": {
+      "name": "image-orientation",
+      "value": "none | from-image | <angle> | [ <angle>? flip ]",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "the specified keyword, or an <angle>, rounded and normalized (see text), plus optionally a flip keyword",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "image-rendering": {
+      "name": "image-rendering",
+      "value": "auto | smooth | high-quality | crisp-edges | pixelated",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<image>": {
+      "value": "<url> | <cross-fade()> | <gradient>"
+    },
+    "<gradient>": {
+      "value": "<linear-gradient()> | <repeating-linear-gradient()> | <radial-gradient()> | <repeating-radial-gradient()>"
+    },
+    "<linear-gradient()>": {
+      "value": "linear-gradient( [ <angle> | to <side-or-corner> ]? , <color-stop-list> )"
+    },
+    "<side-or-corner>": {
+      "value": "[left | right] || [top | bottom]"
+    },
+    "<color-stop-list>": {
+      "value": "<color-stop>#{2,}"
+    },
+    "<color-stop>": {
+      "value": "<color> <length-percentage>?"
+    },
+    "<radial-gradient()>": {
+      "value": "radial-gradient( [ [ circle || <length> ] [ at <position> ]? , | [ ellipse || <length-percentage>{2} ] [ at <position> ]? , | [ [ circle | ellipse ] || <extent-keyword> ] [ at <position> ]? , | at <position> , ]? <color-stop> [ , <color-stop> ]+ )"
+    },
+    "<extent-keyword>": {
+      "value": "closest-corner | closest-side | farthest-corner | farthest-side"
+    },
+    "<ending-shape>": {
+      "prose": "Can be either circle or ellipse; determines whether the gradient’s ending shape is a circle or an ellipse, respectively. If <ending-shape> is omitted, the ending shape defaults to a circle if the <size> is a single <length>, and to an ellipse otherwise."
+    },
+    "<length>": {
+      "prose": "Gives the radius of the circle explicitly. Negative values are invalid. Note: Percentages are not allowed here; they can only be used to specify the size of an elliptical gradient, not a circular one. This restriction exists because there is are multiple reasonable answers as to which dimension the percentage should be relative to. A future level of this module may provide the ability to size circles with percentages, perhaps with more explicit controls over which dimension is used."
+    }
+  }
+}
diff --git a/w3c/css/css-inline.json b/w3c/css/css-inline.json
new file mode 100644
index 000000000000..6eefd2df9a88
--- /dev/null
+++ b/w3c/css/css-inline.json
@@ -0,0 +1,94 @@
+{
+  "properties": {
+    "dominant-baseline": {
+      "name": "dominant-baseline",
+      "value": "auto | text-bottom | alphabetic | ideographic | middle | central | mathematical | hanging | text-top",
+      "initial": "normal",
+      "appliesTo": "block containers, inline boxes, table rows, table columns, grid containers, and flex containers",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "vertical-align": {
+      "name": "vertical-align",
+      "value": "<‘baseline-shift’> || <‘alignment-baseline’>",
+      "initial": "baseline",
+      "appliesTo": "inline-level boxes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "alignment-baseline": {
+      "name": "alignment-baseline",
+      "value": "baseline | text-bottom | alphabetic | ideographic | middle | central | mathematical | text-top | bottom | center | top",
+      "initial": "baseline",
+      "appliesTo": "inline-level boxes, flex items, grid items, table cells",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "baseline-shift": {
+      "name": "baseline-shift",
+      "value": "<length> | <percentage> | sub | super",
+      "initial": "0",
+      "appliesTo": "inline-level boxes, flex items, grid items",
+      "inherited": "no",
+      "percentages": "refer to the used value of line-height",
+      "computedValue": "absolute length, percentage, or keyword specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "inline-sizing": {
+      "name": "inline-sizing",
+      "value": "normal | stretch",
+      "initial": "normal",
+      "appliesTo": "inline boxes",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "initial-letters": {
+      "name": "initial-letters",
+      "value": "normal | [<number> <integer>?]",
+      "initial": "normal",
+      "appliesTo": "certain inline-level boxes and ::first-letter and inside ::marker boxes (see prose)",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "initial-letters-align": {
+      "name": "initial-letters-align",
+      "value": "border-box? [ alphabetic | ideographic | hebrew | hanging ] | border-box",
+      "initial": "alphabetic",
+      "appliesTo": "certain inline-level boxes and ::first-letter and inside ::marker boxes (see prose)",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "initial-letters-wrap": {
+      "name": "initial-letters-wrap",
+      "value": "none | first | all | grid | <length> | <percentage>",
+      "initial": "none",
+      "appliesTo": "certain inline-level boxes and ::first-letter and inside ::marker boxes (see prose)",
+      "inherited": "yes",
+      "percentages": "relative to logical width of (last fragment of) initial letter",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-line-grid.json b/w3c/css/css-line-grid.json
new file mode 100644
index 000000000000..fb2a5b1e7807
--- /dev/null
+++ b/w3c/css/css-line-grid.json
@@ -0,0 +1,39 @@
+{
+  "properties": {
+    "line-grid": {
+      "name": "line-grid",
+      "value": "match-parent | create",
+      "initial": "match-parent",
+      "appliesTo": "block, flex and grid containers",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "line-snap": {
+      "name": "line-snap",
+      "value": "none | baseline | contain",
+      "initial": "none",
+      "appliesTo": "block container elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "box-snap": {
+      "name": "box-snap",
+      "value": "none | block-start | block-end | center | baseline | last-baseline",
+      "initial": "none",
+      "appliesTo": "block-level boxes and internal table elements except table cells",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-lists.json b/w3c/css/css-lists.json
new file mode 100644
index 000000000000..b58193ee6cd5
--- /dev/null
+++ b/w3c/css/css-lists.json
@@ -0,0 +1,106 @@
+{
+  "properties": {
+    "list-style-image": {
+      "name": "list-style-image",
+      "value": "<image> | none",
+      "initial": "none",
+      "appliesTo": "list items",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "computed value of the <image>, or none",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "list-style-type": {
+      "name": "list-style-type",
+      "value": "<counter-style> | <string> | none",
+      "initial": "disc",
+      "appliesTo": "list items",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "list-style-position": {
+      "name": "list-style-position",
+      "value": "inside | outside",
+      "initial": "outside",
+      "appliesTo": "list items",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value (but see prose)",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "list-style": {
+      "name": "list-style",
+      "value": "<‘list-style-type’> || <‘list-style-position’> || <‘list-style-image’>",
+      "initial": "see individual properties",
+      "appliesTo": "list items",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "position": {
+      "name": "position",
+      "newValues": "marker",
+      "computedValue": "see prose, otherwise same as normal"
+    },
+    "marker-side": {
+      "name": "marker-side",
+      "value": "list-item | list-container",
+      "initial": "list-item",
+      "appliesTo": "list items",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "counter-reset": {
+      "name": "counter-reset",
+      "value": "[ <custom-ident> <integer>? ]+ | none",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "counter-set": {
+      "name": "counter-set",
+      "value": "[ <custom-ident> <integer>? ]+ | none",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "counter-increment": {
+      "name": "counter-increment",
+      "value": "[ <custom-ident> <integer>? ]+ | none",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<counter()>": {
+      "value": "counter( <custom-ident>, [ <counter-style> | none ]? )"
+    },
+    "<counters()>": {
+      "value": "counters( <custom-ident>, <string>, [ <counter-style> | none ]? )"
+    }
+  }
+}
diff --git a/w3c/css/css-logical.json b/w3c/css/css-logical.json
new file mode 100644
index 000000000000..ff0994717edf
--- /dev/null
+++ b/w3c/css/css-logical.json
@@ -0,0 +1,587 @@
+{
+  "properties": {
+    "caption-side": {
+      "name": "caption-side",
+      "newValues": "inline-start | inline-end"
+    },
+    "float": {
+      "name": "float",
+      "newValues": "inline-start | inline-end"
+    },
+    "clear": {
+      "name": "clear",
+      "newValues": "inline-start | inline-end"
+    },
+    "text-align": {
+      "name": "text-align",
+      "newValues": "start | end"
+    },
+    "resize": {
+      "name": "resize",
+      "newValues": "block | inline"
+    },
+    "block-size": {
+      "name": "block-size",
+      "value": "<‘width’>",
+      "initial": "auto",
+      "appliesTo": "Same as width and height",
+      "inherited": "No",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as width, height",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as width, height"
+    },
+    "inline-size": {
+      "name": "inline-size",
+      "value": "<‘width’>",
+      "initial": "auto",
+      "appliesTo": "Same as width and height",
+      "inherited": "No",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as width, height",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as width, height"
+    },
+    "min-block-size": {
+      "name": "min-block-size",
+      "value": "<‘min-width’>",
+      "initial": "0",
+      "appliesTo": "same as width and height",
+      "inherited": "No",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as min-width, min-height",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as min-width, min-height"
+    },
+    "min-inline-size": {
+      "name": "min-inline-size",
+      "value": "<‘min-width’>",
+      "initial": "0",
+      "appliesTo": "same as width and height",
+      "inherited": "No",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as min-width, min-height",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as min-width, min-height"
+    },
+    "max-block-size": {
+      "name": "max-block-size",
+      "value": "<‘max-width’>",
+      "initial": "none",
+      "appliesTo": "same as width and height",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as max-width, max-height",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as max-width, max-height"
+    },
+    "max-inline-size": {
+      "name": "max-inline-size",
+      "value": "<‘max-width’>",
+      "initial": "none",
+      "appliesTo": "same as width and height",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as max-width, max-height",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as max-width, max-height"
+    },
+    "margin-block-start": {
+      "name": "margin-block-start",
+      "value": "<‘margin-top’>",
+      "initial": "0",
+      "appliesTo": "Same as margin-top",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding margin-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as margin-top"
+    },
+    "margin-block-end": {
+      "name": "margin-block-end",
+      "value": "<‘margin-top’>",
+      "initial": "0",
+      "appliesTo": "Same as margin-top",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding margin-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as margin-top"
+    },
+    "margin-inline-start": {
+      "name": "margin-inline-start",
+      "value": "<‘margin-top’>",
+      "initial": "0",
+      "appliesTo": "Same as margin-top",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding margin-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as margin-top"
+    },
+    "margin-inline-end": {
+      "name": "margin-inline-end",
+      "value": "<‘margin-top’>",
+      "initial": "0",
+      "appliesTo": "Same as margin-top",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding margin-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as margin-top"
+    },
+    "margin-block": {
+      "name": "margin-block",
+      "value": "<‘margin-left’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "margin-inline": {
+      "name": "margin-inline",
+      "value": "<‘margin-left’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "inset-block-start": {
+      "name": "inset-block-start",
+      "value": "<‘top’>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding top/right/bottom/left properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as top"
+    },
+    "inset-block-end": {
+      "name": "inset-block-end",
+      "value": "<‘top’>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding top/right/bottom/left properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as top"
+    },
+    "inset-inline-start": {
+      "name": "inset-inline-start",
+      "value": "<‘top’>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding top/right/bottom/left properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as top"
+    },
+    "inset-inline-end": {
+      "name": "inset-inline-end",
+      "value": "<‘top’>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding top/right/bottom/left properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as top"
+    },
+    "inset-block": {
+      "name": "inset-block",
+      "value": "<‘top’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "inset-inline": {
+      "name": "inset-inline",
+      "value": "<‘top’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "inset": {
+      "name": "inset",
+      "value": "<‘top’>{1,4}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "padding-block-start": {
+      "name": "padding-block-start",
+      "value": "<‘padding-top’>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding padding-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as padding-top"
+    },
+    "padding-block-end": {
+      "name": "padding-block-end",
+      "value": "<‘padding-top’>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding padding-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as padding-top"
+    },
+    "padding-inline-start": {
+      "name": "padding-inline-start",
+      "value": "<‘padding-top’>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding padding-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as padding-top"
+    },
+    "padding-inline-end": {
+      "name": "padding-inline-end",
+      "value": "<‘padding-top’>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding padding-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as padding-top"
+    },
+    "padding-block": {
+      "name": "padding-block",
+      "value": "<‘padding-left’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "padding-inline": {
+      "name": "padding-inline",
+      "value": "<‘padding-left’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-block-start-width": {
+      "name": "border-block-start-width",
+      "value": "<‘border-top-width’>",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-width properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-width"
+    },
+    "border-block-end-width": {
+      "name": "border-block-end-width",
+      "value": "<‘border-top-width’>",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-width properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-width"
+    },
+    "border-inline-start-width": {
+      "name": "border-inline-start-width",
+      "value": "<‘border-top-width’>",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-width properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-width"
+    },
+    "border-inline-end-width": {
+      "name": "border-inline-end-width",
+      "value": "<‘border-top-width’>",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-width properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-width"
+    },
+    "border-block-width": {
+      "name": "border-block-width",
+      "value": "<‘border-top-width’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-inline-width": {
+      "name": "border-inline-width",
+      "value": "<‘border-top-width’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-block-start-style": {
+      "name": "border-block-start-style",
+      "value": "<‘border-top-style’>",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-style properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-style"
+    },
+    "border-block-end-style": {
+      "name": "border-block-end-style",
+      "value": "<‘border-top-style’>",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-style properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-style"
+    },
+    "border-inline-start-style": {
+      "name": "border-inline-start-style",
+      "value": "<‘border-top-style’>",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-style properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-style"
+    },
+    "border-inline-end-style": {
+      "name": "border-inline-end-style",
+      "value": "<‘border-top-style’>",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-style properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-style"
+    },
+    "border-block-style": {
+      "name": "border-block-style",
+      "value": "<‘border-top-style’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-inline-style": {
+      "name": "border-inline-style",
+      "value": "<‘border-top-style’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-block-start-color": {
+      "name": "border-block-start-color",
+      "value": "<‘border-top-color’>",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-color properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-color"
+    },
+    "border-block-end-color": {
+      "name": "border-block-end-color",
+      "value": "<‘border-top-color’>",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-color properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-color"
+    },
+    "border-inline-start-color": {
+      "name": "border-inline-start-color",
+      "value": "<‘border-top-color’>",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-color properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-color"
+    },
+    "border-inline-end-color": {
+      "name": "border-inline-end-color",
+      "value": "<‘border-top-color’>",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-color properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-color"
+    },
+    "border-block-color": {
+      "name": "border-block-color",
+      "value": "<‘border-top-color’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-inline-color": {
+      "name": "border-inline-color",
+      "value": "<‘border-top-color’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-block-start": {
+      "name": "border-block-start",
+      "value": "<‘border-top-width’> || <‘border-top-style’> || <color>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-block-end": {
+      "name": "border-block-end",
+      "value": "<‘border-top-width’> || <‘border-top-style’> || <color>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-inline-start": {
+      "name": "border-inline-start",
+      "value": "<‘border-top-width’> || <‘border-top-style’> || <color>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-inline-end": {
+      "name": "border-inline-end",
+      "value": "<‘border-top-width’> || <‘border-top-style’> || <color>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-block": {
+      "name": "border-block",
+      "value": "<‘border-block-start’>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-inline": {
+      "name": "border-inline",
+      "value": "<‘border-block-start’>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "background-image-transform": {
+      "name": "background-image-transform",
+      "value": "logical | physical | rotate",
+      "initial": "physical",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "discrete"
+    },
+    "border-image-transform": {
+      "name": "border-image-transform",
+      "value": "logical | physical | rotate",
+      "initial": "rotate",
+      "appliesTo": "All elements, except internal table elements when border-collapse is collapse",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-masking.json b/w3c/css/css-masking.json
new file mode 100644
index 000000000000..886916abfa75
--- /dev/null
+++ b/w3c/css/css-masking.json
@@ -0,0 +1,274 @@
+{
+  "properties": {
+    "clip-path": {
+      "name": "clip-path",
+      "value": "<clip-source> | [ <basic-shape> || <geometry-box> ] | none",
+      "initial": "none",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, but with <url> values made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as specified for <basic-shape> [CSS-SHAPES], otherwise no"
+    },
+    "clip-rule": {
+      "name": "clip-rule",
+      "value": "nonzero | evenodd",
+      "initial": "nonzero",
+      "appliesTo": "Applies to SVG graphics elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-image": {
+      "name": "mask-image",
+      "value": "<mask-reference>#",
+      "initial": "none",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, but with URIs made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-mode": {
+      "name": "mask-mode",
+      "value": "<masking-mode>#",
+      "initial": "match-source",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-repeat": {
+      "name": "mask-repeat",
+      "value": "<repeat-style>#",
+      "initial": "repeat",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Consists of: two keywords, one per dimension",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-position": {
+      "name": "mask-position",
+      "value": "<position>#",
+      "initial": "0% 0%",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "refer to size of mask painting area minus size of mask layer image; see text background-position [CSS3BG]",
+      "computedValue": "Consisting of: two keywords representing the origin and two offsets from that origin, each given as an absolute length (if given a <length>), otherwise as a percentage.",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of simple list of length, percentage, or calc"
+    },
+    "mask-clip": {
+      "name": "mask-clip",
+      "value": "[ <geometry-box> | no-clip ]#",
+      "initial": "border-box",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-origin": {
+      "name": "mask-origin",
+      "value": "<geometry-box>#",
+      "initial": "border-box",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-size": {
+      "name": "mask-size",
+      "value": "<bg-size>#",
+      "initial": "auto",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, but with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of simple list of length, percentage, or calc (This means keyword values are not animatable.)"
+    },
+    "mask-composite": {
+      "name": "mask-composite",
+      "value": "<compositing-operator>#",
+      "initial": "add",
+      "appliesTo": "All elements. In SVG, it applies to container elements without the defs element and all graphics elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask": {
+      "name": "mask",
+      "value": "<mask-layer>#",
+      "initial": "see individual properties",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "see individual properties"
+    },
+    "mask-border-source": {
+      "name": "mask-border-source",
+      "value": "none | <image>",
+      "initial": "none",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "none or the image with its URI made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-border-mode": {
+      "name": "mask-border-mode",
+      "value": "luminance | alpha",
+      "initial": "alpha",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-border-slice": {
+      "name": "mask-border-slice",
+      "value": "<number-percentage>{1,4} fill?",
+      "initial": "0",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "refer to size of the mask border image",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-border-width": {
+      "name": "mask-border-width",
+      "value": "[ <length-percentage> | <number> | auto ]{1,4}",
+      "initial": "auto",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "relative to width/height of the mask border image area",
+      "computedValue": "all <length>s made absolute, otherwise as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-border-outset": {
+      "name": "mask-border-outset",
+      "value": "[ <length> | <number> ]{1,4}",
+      "initial": "0",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "all <length>s made absolute, otherwise as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-border-repeat": {
+      "name": "mask-border-repeat",
+      "value": "[ stretch | repeat | round | space ]{1,2}",
+      "initial": "stretch",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-border": {
+      "name": "mask-border",
+      "value": "<‘mask-border-source’> || <‘mask-border-slice’> [ / <‘mask-border-width’>? [ / <‘mask-border-outset’> ]? ]? || <‘mask-border-repeat’> || <‘mask-border-mode’>",
+      "initial": "See individual properties",
+      "appliesTo": "See individual properties",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "See individual properties",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "See individual properties"
+    },
+    "mask-type": {
+      "name": "mask-type",
+      "value": "luminance | alpha",
+      "initial": "luminance",
+      "appliesTo": "mask elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "clip": {
+      "name": "clip",
+      "value": "rect() | auto",
+      "initial": "auto",
+      "appliesTo": "Absolutely positioned elements. In SVG, it applies to elements which establish a new viewport, pattern elements and mask elements.",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as rectangle"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<clip-source>": {
+      "value": "<url>"
+    },
+    "<geometry-box>": {
+      "value": "<shape-box> | fill-box | stroke-box | view-box"
+    },
+    "<mask-reference>": {
+      "value": "none | <image> | <mask-source>"
+    },
+    "<mask-source>": {
+      "value": "<url>"
+    },
+    "<masking-mode>": {
+      "value": "alpha | luminance | match-source"
+    },
+    "<compositing-operator>": {
+      "value": "add | subtract | intersect | exclude"
+    },
+    "<mask-layer>": {
+      "value": "<mask-reference> || <position> [ / <bg-size> ]? ||<repeat-style> || <geometry-box> || [ <geometry-box> | no-clip ] || <compositing-operator> || <masking-mode>"
+    },
+    "<rect()>": {
+      "value": "rect( <top>, <right>, <bottom>, <left> )"
+    },
+    "<url>": {
+      "prose": "A URL reference to a mask element (for example url(commonmasks.svg#mask)) or to a CSS image."
+    }
+  }
+}
diff --git a/w3c/css/css-multicol.json b/w3c/css/css-multicol.json
new file mode 100644
index 000000000000..2d91ec839b9c
--- /dev/null
+++ b/w3c/css/css-multicol.json
@@ -0,0 +1,17 @@
+{
+  "properties": {
+    "column-span": {
+      "name": "column-span",
+      "value": "none | <integer> | all | auto",
+      "initial": "none",
+      "appliesTo": "in-flow block-level elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-overflow.json b/w3c/css/css-overflow.json
new file mode 100644
index 000000000000..474b987d143c
--- /dev/null
+++ b/w3c/css/css-overflow.json
@@ -0,0 +1,54 @@
+{
+  "properties": {
+    "scrollbar-gutter": {
+      "name": "scrollbar-gutter",
+      "value": "auto | [ stable | always ] && both? && force?",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "text-overflow": {
+      "name": "text-overflow",
+      "value": "[ clip | ellipsis | <string> | fade | <fade()> ]{1,2}",
+      "initial": "clip",
+      "appliesTo": "block containers",
+      "inherited": "no",
+      "percentages": "refer to the width of the line box",
+      "computedValue": "As specified, with <length> converted to absolute units",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "continue": {
+      "name": "continue",
+      "value": "auto | overflow | paginate | fragments | discard",
+      "initial": "auto",
+      "appliesTo": "block containers [CSS21], flex containers [CSS3-FLEXBOX], and grid containers [CSS3-GRID-LAYOUT]",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "see below",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "max-lines": {
+      "name": "max-lines",
+      "value": "none | <integer>",
+      "initial": "none",
+      "appliesTo": "fragment boxes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "as integer"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<fade()>": {
+      "value": "fade( <length> | <percentage> )"
+    }
+  }
+}
diff --git a/w3c/css/css-page-floats.json b/w3c/css/css-page-floats.json
new file mode 100644
index 000000000000..bd7e451bfaba
--- /dev/null
+++ b/w3c/css/css-page-floats.json
@@ -0,0 +1,68 @@
+{
+  "properties": {
+    "float-reference": {
+      "name": "float-reference",
+      "value": "inline | column | region | page",
+      "initial": "inline",
+      "appliesTo": "all elements.",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified.",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "float": {
+      "name": "float",
+      "value": "block-start | block-end | inline-start | inline-end | snap-block | <snap-block()> | snap-inline | <snap-inline()> | left | right | top | bottom | none",
+      "initial": "none",
+      "appliesTo": "all elements.",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified.",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "clear": {
+      "name": "clear",
+      "value": "inline-start | inline-end | block-start | block-end | left | right | top | bottom | none",
+      "initial": "none",
+      "appliesTo": "block-level elements, floats, regions, pages",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified.",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "float-defer": {
+      "name": "float-defer",
+      "value": "<integer> | last | none",
+      "initial": "none",
+      "appliesTo": "floats",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified.",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "float-offset": {
+      "name": "float-offset",
+      "value": "<length> | <percentage>",
+      "initial": "0",
+      "appliesTo": "floats",
+      "inherited": "no",
+      "percentages": "see prose",
+      "computedValue": "one absolute length",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<snap-block()>": {
+      "value": "snap-block()"
+    },
+    "<snap-inline()>": {
+      "value": "snap-inline()"
+    }
+  }
+}
diff --git a/w3c/css/css-page.json b/w3c/css/css-page.json
new file mode 100644
index 000000000000..73fcaf857360
--- /dev/null
+++ b/w3c/css/css-page.json
@@ -0,0 +1,52 @@
+{
+  "properties": {
+    "page": {
+      "name": "page",
+      "value": "auto | <custom-ident>",
+      "initial": "auto",
+      "appliesTo": "boxes that create class A break points",
+      "inherited": "no (but see prose)",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {
+    "size": {
+      "name": "size",
+      "for": "@page",
+      "value": "<length>{1,2} | auto | [ <page-size> || [ portrait | landscape ] ]",
+      "initial": "auto",
+      "computedValue": "specified value, with <length>s made absolute."
+    },
+    "marks": {
+      "name": "marks",
+      "for": "@page",
+      "value": "none | [ crop || cross ]",
+      "initial": "none",
+      "computedValue": "as specified"
+    },
+    "bleed": {
+      "name": "bleed",
+      "for": "@page",
+      "value": "auto | <length>",
+      "initial": "auto",
+      "computedValue": "as specified"
+    }
+  },
+  "valuespaces": {
+    "<page-selector-list>": {
+      "value": "<page-selector>#"
+    },
+    "<page-selector>": {
+      "value": "[ <ident-token>? <pseudo-page>* ]!"
+    },
+    "<pseudo-page>": {
+      "value": "':' [ left | right | first | blank ] /* Margin rules */"
+    },
+    "<page-size>": {
+      "prose": "A page size can be specified using one of the following media names. This is the equivalent of specifying size using length values. The definition of the the media names comes from Media Standardized Names [PWGMSN]. A5 Equivalent to the size of ISO A5 media: 148mm wide and 210 mm high. A4 Equivalent to the size of ISO A4 media: 210 mm wide and 297 mm high. A3 Equivalent to the size of ISO A3 media: 297mm wide and 420mm high. B5 Equivalent to the size of ISO B5 media: 176mm wide by 250mm high. B4 Equivalent to the size of ISO B4 media: 250mm wide by 353mm high. JIS-B5 Equivalent to the size of JIS B5 media: 182mm wide by 257mm high. JIS-B4 Equivalent to the size of JIS B4 media: 257mm wide by 364mm high. letter Equivalent to the size of North American letter media: 8.5 inches wide and 11 inches high legal Equivalent to the size of North American legal: 8.5 inches wide by 14 inches high. ledger Equivalent to the size of North American ledger: 11 inches wide by 17 inches high."
+    }
+  }
+}
diff --git a/w3c/css/css-position.json b/w3c/css/css-position.json
new file mode 100644
index 000000000000..047631dd81cf
--- /dev/null
+++ b/w3c/css/css-position.json
@@ -0,0 +1,126 @@
+{
+  "properties": {
+    "position": {
+      "name": "position",
+      "value": "static | relative | absolute | sticky | fixed",
+      "initial": "static",
+      "appliesTo": "all elements except table-column-group and table-column",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "top": {
+      "name": "top",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a '<length>', the corresponding absolute length; if specified as a '<percentage>', the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "right": {
+      "name": "right",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a '<length>', the corresponding absolute length; if specified as a '<percentage>', the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "bottom": {
+      "name": "bottom",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a '<length>', the corresponding absolute length; if specified as a '<percentage>', the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "left": {
+      "name": "left",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a '<length>', the corresponding absolute length; if specified as a '<percentage>', the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "offset-before": {
+      "name": "offset-before",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a <length>, the corresponding absolute length; if specified as a <percentage>, the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "offset-after": {
+      "name": "offset-after",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a <length>, the corresponding absolute length; if specified as a <percentage>, the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "offset-start": {
+      "name": "offset-start",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a <length>, the corresponding absolute length; if specified as a <percentage>, the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "offset-end": {
+      "name": "offset-end",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a <length>, the corresponding absolute length; if specified as a <percentage>, the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "z-index": {
+      "name": "z-index",
+      "value": "auto | <integer>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "<integer>"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<length>": {
+      "prose": "The offset is a fixed distance from the reference edge. Negative values are allowed."
+    },
+    "<percentage>": {
+      "prose": "The offset is a percentage of the containing block’s width (for left or right) or height (for top and bottom). For stickily positioned elements, the offset is a percentage of the flow root’s width (for left or right) or height (for top or bottom). Negative values are allowed."
+    },
+    "<integer>": {
+      "prose": "This integer is the stack level of the generated box in the current stacking context. The box also establishes a new stacking context."
+    }
+  }
+}
diff --git a/w3c/css/css-regions.json b/w3c/css/css-regions.json
new file mode 100644
index 000000000000..6c3518b1a9af
--- /dev/null
+++ b/w3c/css/css-regions.json
@@ -0,0 +1,72 @@
+{
+  "properties": {
+    "flow-into": {
+      "name": "flow-into",
+      "value": "none | <ident> [element|content]?",
+      "initial": "none",
+      "appliesTo": "All elements, but not pseudo-elements such as ::first-line, ::first-letter, ::before or ::after.",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "flow-from": {
+      "name": "flow-from",
+      "value": "<ident> | none | inherit",
+      "initial": "none",
+      "appliesTo": "Non-replaced block containers. This might be expanded in future versions of the specification to allow other types of containers to receive flow content.",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "break-before": {
+      "name": "break-before",
+      "value": "auto | always | avoid | left | right | page | column | region | avoid-page | avoid-column | avoid-region",
+      "initial": "auto",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "break-after": {
+      "name": "break-after",
+      "value": "auto | always | avoid | left | right | page | column | region | avoid-page | avoid-column | avoid-region",
+      "initial": "auto",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "break-inside": {
+      "name": "break-inside",
+      "value": "auto | avoid | avoid-page | avoid-column | avoid-region",
+      "initial": "auto",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "region-fragment": {
+      "name": "region-fragment",
+      "value": "auto | break",
+      "initial": "auto",
+      "appliesTo": "CSS Regions",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-rhythm.json b/w3c/css/css-rhythm.json
new file mode 100644
index 000000000000..db6b4c00f1ab
--- /dev/null
+++ b/w3c/css/css-rhythm.json
@@ -0,0 +1,72 @@
+{
+  "properties": {
+    "block-step-size": {
+      "name": "block-step-size",
+      "value": "none | <length>",
+      "initial": "none",
+      "appliesTo": "block-level boxes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "keyword or absolute length",
+      "canonicalOrder": "per grammar",
+      "animatable": "???"
+    },
+    "block-step-insert": {
+      "name": "block-step-insert",
+      "value": "margin | padding",
+      "initial": "margin",
+      "appliesTo": "block-level boxes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "block-step-align": {
+      "name": "block-step-align",
+      "value": "auto | center | start | end",
+      "initial": "auto",
+      "appliesTo": "block-level boxes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "block-step-round": {
+      "name": "block-step-round",
+      "value": "up | down | nearest",
+      "initial": "up",
+      "appliesTo": "block-level boxes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "block-step": {
+      "name": "block-step",
+      "value": "<‘block-step-size’> || <‘block-step-insert’> || <‘block-step-align’> || <‘block-step-round’>",
+      "initial": "See individual properties",
+      "appliesTo": "block-level boxes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "See individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "See individual properties"
+    },
+    "line-height-step": {
+      "name": "line-height-step",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "the absolute length",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-round-display.json b/w3c/css/css-round-display.json
new file mode 100644
index 000000000000..9b4615c7fd89
--- /dev/null
+++ b/w3c/css/css-round-display.json
@@ -0,0 +1,43 @@
+{
+  "properties": {
+    "shape-inside": {
+      "name": "shape-inside",
+      "value": "auto | outside-shape | [ <basic-shape> || shape-box ] | <image> | display",
+      "initial": "auto",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "computed lengths for <basic-shape>, the absolute URI for <uri>, otherwise as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "as specified for <basic-shape>, otherwise no"
+    },
+    "border-boundary": {
+      "name": "border-boundary",
+      "value": "none | parent | display",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {
+    "shape": {
+      "name": "shape",
+      "for": "@media",
+      "value": "rect | round",
+      "type": "discrete"
+    },
+    "viewport-fit": {
+      "name": "viewport-fit",
+      "for": "@viewport",
+      "value": "auto | contain | cover",
+      "initial": "auto",
+      "percentages": "N/A",
+      "computedValue": "as specified"
+    }
+  },
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-ruby.json b/w3c/css/css-ruby.json
new file mode 100644
index 000000000000..8736ba4db8d4
--- /dev/null
+++ b/w3c/css/css-ruby.json
@@ -0,0 +1,43 @@
+{
+  "properties": {
+    "display": {
+      "name": "display",
+      "newValues": "ruby | ruby-base | ruby-text | ruby-base-container | ruby-text-container"
+    },
+    "ruby-position": {
+      "name": "ruby-position",
+      "value": "over | under | inter-character",
+      "initial": "over",
+      "appliesTo": "ruby annotation containers",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "ruby-merge": {
+      "name": "ruby-merge",
+      "value": "separate | collapse | auto",
+      "initial": "separate",
+      "appliesTo": "ruby annotation containers",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "ruby-align": {
+      "name": "ruby-align",
+      "value": "start | center | space-between | space-around",
+      "initial": "space-around",
+      "appliesTo": "ruby bases, ruby annotations, ruby base containers, ruby annotation containers",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-scroll-anchoring.json b/w3c/css/css-scroll-anchoring.json
new file mode 100644
index 000000000000..646262873b09
--- /dev/null
+++ b/w3c/css/css-scroll-anchoring.json
@@ -0,0 +1,17 @@
+{
+  "properties": {
+    "overflow-anchor": {
+      "name": "overflow-anchor",
+      "value": "auto | none",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-scroll-snap.json b/w3c/css/css-scroll-snap.json
new file mode 100644
index 000000000000..749882e20b51
--- /dev/null
+++ b/w3c/css/css-scroll-snap.json
@@ -0,0 +1,281 @@
+{
+  "properties": {
+    "scroll-snap-type": {
+      "name": "scroll-snap-type",
+      "value": "none | [ x | y | block | inline | both ] [ mandatory | proximity ]?",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "scroll-padding": {
+      "name": "scroll-padding",
+      "value": "[ <length-percentage> | auto ]{1,4}",
+      "initial": "auto",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the corresponding dimension of the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-margin": {
+      "name": "scroll-margin",
+      "value": "<length>{1,4}",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-snap-align": {
+      "name": "scroll-snap-align",
+      "value": "[ none | start | end | center ]{1,2}",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "two keywords",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "scroll-snap-stop": {
+      "name": "scroll-snap-stop",
+      "value": "normal | always",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "scroll-padding-top": {
+      "name": "scroll-padding-top",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-right": {
+      "name": "scroll-padding-right",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-bottom": {
+      "name": "scroll-padding-bottom",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-left": {
+      "name": "scroll-padding-left",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-inline-start": {
+      "name": "scroll-padding-inline-start",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-block-start": {
+      "name": "scroll-padding-block-start",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-inline-end": {
+      "name": "scroll-padding-inline-end",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-block-end": {
+      "name": "scroll-padding-block-end",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-block": {
+      "name": "scroll-padding-block",
+      "value": "<length-percentage>{1,2}",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-inline": {
+      "name": "scroll-padding-inline",
+      "value": "<length-percentage>{1,2}",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-margin-top": {
+      "name": "scroll-margin-top",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-right": {
+      "name": "scroll-margin-right",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-bottom": {
+      "name": "scroll-margin-bottom",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-left": {
+      "name": "scroll-margin-left",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-block-start": {
+      "name": "scroll-margin-block-start",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-inline-start": {
+      "name": "scroll-margin-inline-start",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-block-end": {
+      "name": "scroll-margin-block-end",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-inline-end": {
+      "name": "scroll-margin-inline-end",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-block": {
+      "name": "scroll-margin-block",
+      "value": "<length>{1,2}",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-inline": {
+      "name": "scroll-margin-inline",
+      "value": "<length>{1,2}",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-scrollbars.json b/w3c/css/css-scrollbars.json
new file mode 100644
index 000000000000..1a19e0664421
--- /dev/null
+++ b/w3c/css/css-scrollbars.json
@@ -0,0 +1,39 @@
+{
+  "properties": {
+    "scrollbar-face-color": {
+      "name": "scrollbar-face-color",
+      "value": "auto | <color>",
+      "initial": "auto",
+      "appliesTo": "boxes to which overflow applies",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "the computed color or the keyword auto",
+      "canonicalOrder": "per grammar",
+      "animationType": "color"
+    },
+    "scrollbar-track-color": {
+      "name": "scrollbar-track-color",
+      "value": "auto | <color>",
+      "initial": "auto",
+      "appliesTo": "boxes to which overflow applies",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "the computed color or the keyword auto",
+      "canonicalOrder": "per grammar",
+      "animationType": "color"
+    },
+    "scrollbar-width": {
+      "name": "scrollbar-width",
+      "value": "auto | thin | <length>",
+      "initial": "auto",
+      "appliesTo": "boxes to which overflow applies",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "absolute length or the keyword auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-shadow-parts.json b/w3c/css/css-shadow-parts.json
new file mode 100644
index 000000000000..f6be40493cac
--- /dev/null
+++ b/w3c/css/css-shadow-parts.json
@@ -0,0 +1,12 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<::part()>": {
+      "value": "::part( <ident> )"
+    },
+    "<::theme()>": {
+      "value": "::theme( <ident> )"
+    }
+  }
+}
diff --git a/w3c/css/css-shapes.json b/w3c/css/css-shapes.json
new file mode 100644
index 000000000000..9063f0b53f22
--- /dev/null
+++ b/w3c/css/css-shapes.json
@@ -0,0 +1,38 @@
+{
+  "properties": {
+    "shape-inside": {
+      "name": "shape-inside",
+      "value": "auto | outside-shape | [ <basic-shape> || shape-box ] | <image> | display",
+      "initial": "auto",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "computed lengths for <basic-shape>, the absolute URI for <uri>, otherwise as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "as specified for <basic-shape>, otherwise no"
+    },
+    "shape-padding": {
+      "name": "shape-padding",
+      "value": "<length>",
+      "initial": "none",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "the absolute length",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<path()>": {
+      "value": "path( [<fill-rule>,]? <string> )"
+    },
+    "<basic-shape>": {
+      "prose": "The shape is computed based on the values of one of inset(), circle(), ellipse() or polygon()."
+    },
+    "<uri>": {
+      "prose": "If the <uri> references an SVG shape element, that element defines the shape. Otherwise, if the <uri> references an image, the shape is extracted and computed based on the alpha channel of the specified image. If the <uri> does not reference an SVG shape element or an image, the effect is as if the value auto had been specified."
+    }
+  }
+}
diff --git a/w3c/css/css-size-adjust.json b/w3c/css/css-size-adjust.json
new file mode 100644
index 000000000000..ba70d343ccf6
--- /dev/null
+++ b/w3c/css/css-size-adjust.json
@@ -0,0 +1,21 @@
+{
+  "properties": {
+    "text-size-adjust": {
+      "name": "text-size-adjust",
+      "value": "auto | none | <percentage>",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "see below",
+      "computedValue": "as specified",
+      "canonicalOrder": "N/A",
+      "animatable": "as percentage"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<percentage>": {
+      "prose": "When displaying on a small device, renderers must not do size adjustment but instead the computed value of font-size must be multiplied by this percentage. Note: This means that 'text-size-adjust: 100%;' is equivalent to 'text-size-adjust: none;'."
+    }
+  }
+}
diff --git a/w3c/css/css-syntax.json b/w3c/css/css-syntax.json
new file mode 100644
index 000000000000..38293fa7ca92
--- /dev/null
+++ b/w3c/css/css-syntax.json
@@ -0,0 +1,15 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<an+b>": {
+      "value": "odd | even | <integer> | <n-dimension> | '+'? n | -n | <ndashdigit-dimension> | '+'? <ndashdigit-ident> | <dashndashdigit-ident> | <n-dimension> <signed-integer> | '+'? n <signed-integer> | -n <signed-integer> | <ndash-dimension> <signless-integer> | '+'? n- <signless-integer> | -n- <signless-integer> | <n-dimension> ['+' | '-'] <signless-integer> '+'? n ['+' | '-'] <signless-integer> | -n ['+' | '-'] <signless-integer>"
+    },
+    "<urange>": {
+      "value": "u '+' <ident-token> '?'* | u <dimension-token> '?'* | u <number-token> '?'* | u <number-token> <dimension-token> | u <number-token> <number-token> | u '+' '?'+"
+    },
+    "<EOF-token>": {
+      "prose": "A conceptual token representing the end of the list of tokens. Whenever the list of tokens is empty, the next input token is always an <EOF-token>."
+    }
+  }
+}
diff --git a/w3c/css/css-tables.json b/w3c/css/css-tables.json
new file mode 100644
index 000000000000..ded491ca8802
--- /dev/null
+++ b/w3c/css/css-tables.json
@@ -0,0 +1,61 @@
+{
+  "properties": {
+    "table-layout": {
+      "name": "table-layout",
+      "value": "auto | fixed",
+      "initial": "auto",
+      "appliesTo": "table-root boxes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-collapse": {
+      "name": "border-collapse",
+      "value": "separate | collapse",
+      "initial": "separate",
+      "appliesTo": "table-root boxes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-spacing": {
+      "name": "border-spacing",
+      "value": "<​length​>{1,2}",
+      "initial": "0px 0px",
+      "appliesTo": "table-root boxes when border-collapse is separate",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "two absolute lengths",
+      "canonicalOrder": "per grammar",
+      "animatable": "yes"
+    },
+    "caption-side": {
+      "name": "caption-side",
+      "value": "top | bottom",
+      "initial": "top",
+      "appliesTo": "table-caption boxes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "empty-cells": {
+      "name": "empty-cells",
+      "value": "show | hide",
+      "initial": "show",
+      "appliesTo": "table-cell boxes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-text-decor.json b/w3c/css/css-text-decor.json
new file mode 100644
index 000000000000..2a4bf6f99024
--- /dev/null
+++ b/w3c/css/css-text-decor.json
@@ -0,0 +1,72 @@
+{
+  "properties": {
+    "text-decoration-line": {
+      "name": "text-decoration-line",
+      "value": "none | [ underline || overline || line-through || blink ] | spelling-error | grammar-error",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no (but see prose, above)",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "text-decoration-width": {
+      "name": "text-decoration-width",
+      "value": "auto | from-font | <length>",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "text-underline-offset": {
+      "name": "text-underline-offset",
+      "value": "auto | from-font | <length>",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "text-decoration-skip": {
+      "name": "text-decoration-skip",
+      "value": "none | [ objects || [ spaces | [ leading-spaces || trailing-spaces ] ] || edges || box-decoration ]",
+      "initial": "objects leading-spaces trailing-spaces",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "text-decoration-skip-ink": {
+      "name": "text-decoration-skip-ink",
+      "value": "auto | none",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "text-emphasis-skip": {
+      "name": "text-emphasis-skip",
+      "value": "spaces || punctuation || symbols || narrow",
+      "initial": "spaces punctuation",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/css-text.json b/w3c/css/css-text.json
new file mode 100644
index 000000000000..6016f392b2e6
--- /dev/null
+++ b/w3c/css/css-text.json
@@ -0,0 +1,151 @@
+{
+  "properties": {
+    "text-space-collapse": {
+      "name": "text-space-collapse",
+      "value": "collapse | discard | preserve | preserve-breaks | preserve-spaces",
+      "initial": "collapse",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "text-space-trim": {
+      "name": "text-space-trim",
+      "value": "none | trim-inner || discard-before || discard-after",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "text-wrap": {
+      "name": "text-wrap",
+      "value": "wrap | nowrap | balance | multi-line",
+      "initial": "wrap",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "wrap-before": {
+      "name": "wrap-before",
+      "value": "auto | avoid | avoid-line | avoid-flex | line | flex",
+      "initial": "auto",
+      "appliesTo": "inline-level boxes and flex items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "wrap-after": {
+      "name": "wrap-after",
+      "value": "auto | avoid | avoid-line | avoid-flex | line | flex",
+      "initial": "auto",
+      "appliesTo": "inline-level boxes and flex items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "wrap-inside": {
+      "name": "wrap-inside",
+      "value": "auto | avoid",
+      "initial": "auto",
+      "appliesTo": "inline boxes",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "white-space": {
+      "name": "white-space",
+      "value": "normal | pre | nowrap | pre-wrap | pre-line",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "hyphenate-character": {
+      "name": "hyphenate-character",
+      "value": "auto | <string>",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "hyphenate-limit-zone": {
+      "name": "hyphenate-limit-zone",
+      "value": "<percentage> | <length>",
+      "initial": "0",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "refers to width of the line box",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "hyphenate-limit-chars": {
+      "name": "hyphenate-limit-chars",
+      "value": "[ auto | <integer> ]{1,3}",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "hyphenate-limit-lines": {
+      "name": "hyphenate-limit-lines",
+      "value": "no-limit | <integer>",
+      "initial": "no-limit",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "hyphenate-limit-last": {
+      "name": "hyphenate-limit-last",
+      "value": "none | always | column | page | spread",
+      "initial": "none",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "text-spacing": {
+      "name": "text-spacing",
+      "value": "normal | none | [ trim-start | space-start ] || [ trim-end | space-end | allow-end ] || [ trim-adjacent | space-adjacent ] || no-compress || ideograph-alpha || ideograph-numeric || punctuation",
+      "initial": "normal",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computed value": "specified value"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<string>": {
+      "prose": "The string must be a single character; otherwise the declaration must be ignored. When applied to a table cell, specifies the alignment character around which the cell’s contents will align. See below for further details and how this value combines with keywords."
+    }
+  }
+}
diff --git a/w3c/css/css-timing.json b/w3c/css/css-timing.json
new file mode 100644
index 000000000000..048fa77ff2cd
--- /dev/null
+++ b/w3c/css/css-timing.json
@@ -0,0 +1,24 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<cubic-bezier()>": {
+      "value": "cubic-bezier(<number>, <number>, <number>, <number>)"
+    },
+    "<steps()>": {
+      "value": "steps(<integer>[, [ start | end ] ]?)"
+    },
+    "<timing-function>": {
+      "value": "linear | <cubic-bezier-timing-function> | <step-timing-function> | <frames-timing-function>"
+    },
+    "<cubic-bezier-timing-function>": {
+      "value": "ease | ease-in | ease-out | ease-in-out | cubic-bezier(<number>, <number>, <number>, <number>)"
+    },
+    "<step-timing-function>": {
+      "value": "step-start | step-end | steps(<integer>[, [ start | end ] ]?)"
+    },
+    "<frames-timing-function>": {
+      "value": "frames(<integer>)"
+    }
+  }
+}
diff --git a/w3c/css/css-transforms.json b/w3c/css/css-transforms.json
new file mode 100644
index 000000000000..200e20e5f1f5
--- /dev/null
+++ b/w3c/css/css-transforms.json
@@ -0,0 +1,114 @@
+{
+  "properties": {
+    "translate": {
+      "name": "translate",
+      "value": "none | <length-percentage> [ <length-percentage> <length>? ]?",
+      "initial": "none",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "relative to the width of the containing block (for the first value) or the height (for the second value)",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as <length> or <percentage> list"
+    },
+    "rotate": {
+      "name": "rotate",
+      "value": "none | [ x | y | z | <number>{3} ]? && <angle>",
+      "initial": "none",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "as SLERP"
+    },
+    "scale": {
+      "name": "scale",
+      "value": "none | <number>{1,3}",
+      "initial": "none",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "as <number> list"
+    },
+    "transform-style": {
+      "name": "transform-style",
+      "value": "auto | flat | preserve-3d",
+      "initial": "auto",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "Same as specified value.",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "perspective": {
+      "name": "perspective",
+      "value": "none | <length>",
+      "initial": "none",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "Absolute length or \"none\".",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "perspective-origin": {
+      "name": "perspective-origin",
+      "value": "<position>",
+      "initial": "50% 50%",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "refer to the size of the reference box",
+      "computedValue": "For <length> the absolute value, otherwise a percentage.",
+      "canonicalOrder": "per grammar",
+      "animatable": "as simple list of length, percentage, or calc"
+    },
+    "backface-visibility": {
+      "name": "backface-visibility",
+      "value": "visible | hidden",
+      "initial": "visible",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "Same as specified value.",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<matrix3d()>": {
+      "value": "matrix3d( <number> [, <number> ]{15,15} )"
+    },
+    "<translate3d()>": {
+      "value": "translate3d( <length-percentage> , <length-percentage> , <length> )"
+    },
+    "<translateZ()>": {
+      "value": "translateZ( <length> )"
+    },
+    "<scale3d()>": {
+      "value": "scale3d( <number> , <number>, <number> )"
+    },
+    "<scaleZ()>": {
+      "value": "scaleZ( <number> )"
+    },
+    "<rotate3d()>": {
+      "value": "rotate3d( <number> , <number> , <number> , [ <angle> | <zero> ] )"
+    },
+    "<rotateX()>": {
+      "value": "rotateX( [ <angle> | <zero> ] )"
+    },
+    "<rotateY()>": {
+      "value": "rotateY( [ <angle> | <zero> ] )"
+    },
+    "<rotateZ()>": {
+      "value": "rotateZ( [ <angle> | <zero> ] )"
+    },
+    "<perspective()>": {
+      "value": "perspective( <length> )"
+    }
+  }
+}
diff --git a/w3c/css/css-ui.json b/w3c/css/css-ui.json
new file mode 100644
index 000000000000..0f00db12ddf5
--- /dev/null
+++ b/w3c/css/css-ui.json
@@ -0,0 +1,189 @@
+{
+  "properties": {
+    "outline": {
+      "name": "outline",
+      "value": "[ <‘outline-color’> || <‘outline-style’> || <‘outline-width’> ]",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animationType": "see individual properties"
+    },
+    "outline-width": {
+      "name": "outline-width",
+      "value": "<line-width>",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "absolute length; 0 if the outline style is none.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length"
+    },
+    "outline-style": {
+      "name": "outline-style",
+      "value": "auto | <outline-line-style>",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "outline-color": {
+      "name": "outline-color",
+      "value": "<color> | invert",
+      "initial": "invert",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "The computed value for invert is invert. For <color> values, see resolving color values in [CSS-COLOR-4].",
+      "canonicalOrder": "per grammar",
+      "animationType": "color"
+    },
+    "outline-offset": {
+      "name": "outline-offset",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "<length> value in absolute units (px or physical).",
+      "canonicalOrder": "per grammar",
+      "animationType": "length"
+    },
+    "resize": {
+      "name": "resize",
+      "value": "none | both | horizontal | vertical",
+      "initial": "none",
+      "appliesTo": "elements with overflow other than visible, and optionally replaced elements such as images, videos, and iframes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "cursor": {
+      "name": "cursor",
+      "value": "[ [<url> [<x> <y>]?,]* [ auto | default | none | context-menu | help | pointer | progress | wait | cell | crosshair | text | vertical-text | alias | copy | move | no-drop | not-allowed | grab | grabbing | e-resize | n-resize | ne-resize | nw-resize | s-resize | se-resize | sw-resize | w-resize | ew-resize | ns-resize | nesw-resize | nwse-resize | col-resize | row-resize | all-scroll | zoom-in | zoom-out ] ]",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified, except with any relative URLs converted to absolute",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "caret-color": {
+      "name": "caret-color",
+      "value": "auto | <color>",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "The computed value for auto is auto. For <color> values, see resolving color values in [CSS-COLOR-4].",
+      "canonicalOrder": "per grammar",
+      "animationType": "color"
+    },
+    "caret-shape": {
+      "name": "caret-shape",
+      "value": "auto | bar | block | underscore",
+      "initial": "auto",
+      "appliesTo": "elements that accept input",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "Same as specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "caret": {
+      "name": "caret",
+      "value": "<‘caret-color’> || <‘caret-shape’>",
+      "initial": "auto",
+      "appliesTo": "elements that accept input",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "See individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "See individual properties"
+    },
+    "nav-up": {
+      "name": "nav-up",
+      "value": "auto | <id> [ current | root | <target-name> ]?",
+      "initial": "auto",
+      "appliesTo": "all enabled elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "nav-right": {
+      "name": "nav-right",
+      "value": "auto | <id> [ current | root | <target-name> ]?",
+      "initial": "auto",
+      "appliesTo": "all enabled elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "nav-down": {
+      "name": "nav-down",
+      "value": "auto | <id> [ current | root | <target-name> ]?",
+      "initial": "auto",
+      "appliesTo": "all enabled elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "nav-left": {
+      "name": "nav-left",
+      "value": "auto | <id> [ current | root | <target-name> ]?",
+      "initial": "auto",
+      "appliesTo": "all enabled elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "user-select": {
+      "name": "user-select",
+      "value": "auto | text | none | contain | all",
+      "initial": "auto",
+      "appliesTo": "all elements, and optionally to the ::before and ::after pseudo elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "See below",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "appearance": {
+      "name": "appearance",
+      "value": "auto | none",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "As specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<id>": {
+      "prose": "The <id> value is an ID selector [SELECT]. In response to directional navigation input corresponding to the property, the focus is navigated to the first element in tree order matching the selector. If this refers to the currently focused element, the directional navigation input respective to the nav- property is ignored — there is no need to refocus the same element. If no element matches the selector, the user agent automatically determines which element to navigate the focus to. If the focus is navigated to an element that was not otherwise focusable, it becomes focusable only as the result of this directional navigation, and the :focus pseudo-class matches the element while it is focused as such. Note: there were other options under consideration for such \"not otherwise focusable\" elements, including focus to the next otherwise focusable element in the document tree (including descendants of such a not otherwise focusable element). Input on such other options is welcome and explicitly solicited, especially from implementation experiences and author experience using the directional navigation properties in their content."
+    },
+    "<target-name>": {
+      "prose": "The <target-name> parameter indicates the target frame for the focus navigation. It is a <string> and it MUST NOT start with the underscore \"_\" character. Error handling: if it does start with an underscore, \"_parent\" navigates to the parent frame, \"_root\" is treated as root, and other values navigate to a frame by that name if it exists. If the specified target frame does not exist, the parameter will be treated as the keyword current, which means to simply use the frame that the element is in. The keyword root indicates that the user agent should target the full window."
+    }
+  }
+}
diff --git a/w3c/css/css-values.json b/w3c/css/css-values.json
new file mode 100644
index 000000000000..fa2d093dafb3
--- /dev/null
+++ b/w3c/css/css-values.json
@@ -0,0 +1,45 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<url>": {
+      "value": "url( <string> <url-modifier>* )"
+    },
+    "<position>": {
+      "value": "[ [ left | center | right ] || [ top | center | bottom ] | [ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ]? | [ [ left | right ] <length-percentage> ] && [ [ top | bottom ] <length-percentage> ] ]"
+    },
+    "<calc()>": {
+      "value": "calc( <calc-sum> )"
+    },
+    "<min()>": {
+      "value": "min( <calc-sum># )"
+    },
+    "<max()>": {
+      "value": "max( <calc-sum># )"
+    },
+    "<clamp()>": {
+      "value": "clamp( <calc-sum>#{3} )"
+    },
+    "<calc-sum>": {
+      "value": "<calc-product> [ [ '+' | '-' ] <calc-product> ]*"
+    },
+    "<calc-product>": {
+      "value": "<calc-value> [ [ '*' | '/' ] <calc-value> ]*"
+    },
+    "<calc-value>": {
+      "value": "<number> | <dimension> | <percentage> | ( <calc-sum> )"
+    },
+    "<length-percentage>": {
+      "value": "[ <length> | <percentage> ]"
+    },
+    "<frequency-percentage>": {
+      "value": "[ <frequency> | <percentage> ]"
+    },
+    "<angle-percentage>": {
+      "value": "[ <angle> | <percentage> ]"
+    },
+    "<time-percentage>": {
+      "value": "[ <time> | <percentage> ]"
+    }
+  }
+}
diff --git a/w3c/css/css-variables.json b/w3c/css/css-variables.json
new file mode 100644
index 000000000000..0b19ea46b7ed
--- /dev/null
+++ b/w3c/css/css-variables.json
@@ -0,0 +1,9 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<var()>": {
+      "value": "var( <custom-property-name> [, <declaration-value> ]? )"
+    }
+  }
+}
diff --git a/w3c/css/css-will-change.json b/w3c/css/css-will-change.json
new file mode 100644
index 000000000000..54ac19bd82b4
--- /dev/null
+++ b/w3c/css/css-will-change.json
@@ -0,0 +1,21 @@
+{
+  "properties": {
+    "will-change": {
+      "name": "will-change",
+      "value": "auto | <animateable-feature>#",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "not animatable"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<animateable-feature>": {
+      "value": "scroll-position | contents | <custom-ident>"
+    }
+  }
+}
diff --git a/w3c/css/css-writing-modes.json b/w3c/css/css-writing-modes.json
new file mode 100644
index 000000000000..5901f0eaeeb4
--- /dev/null
+++ b/w3c/css/css-writing-modes.json
@@ -0,0 +1,72 @@
+{
+  "properties": {
+    "direction": {
+      "name": "direction",
+      "value": "ltr | rtl",
+      "initial": "ltr",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "n/a",
+      "animationType": "not animatable"
+    },
+    "unicode-bidi": {
+      "name": "unicode-bidi",
+      "value": "normal | embed | isolate | bidi-override | isolate-override | plaintext",
+      "initial": "normal",
+      "appliesTo": "all elements, but see prose",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "not animatable"
+    },
+    "writing-mode": {
+      "name": "writing-mode",
+      "value": "horizontal-tb | vertical-rl | vertical-lr | sideways-rl | sideways-lr",
+      "initial": "horizontal-tb",
+      "appliesTo": "All elements except table row groups, table column groups, table rows, table columns, ruby base container, ruby annotation container",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "n/a",
+      "animationType": "not animatable"
+    },
+    "text-orientation": {
+      "name": "text-orientation",
+      "value": "mixed | upright | sideways",
+      "initial": "mixed",
+      "appliesTo": "all elements except table row groups, rows, column groups, and columns",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "n/a",
+      "animationType": "not animatable"
+    },
+    "glyph-orientation-vertical": {
+      "name": "glyph-orientation-vertical",
+      "value": "auto | 0deg | 90deg | 0 | 90",
+      "initial": "n/a",
+      "appliesTo": "n/a",
+      "inherited": "na/",
+      "percentages": "n/a",
+      "computedValue": "n/a",
+      "canonicalOrder": "n/a",
+      "animatable": "n/a"
+    },
+    "text-combine-upright": {
+      "name": "text-combine-upright",
+      "value": "none | all | [ digits <integer>? ]",
+      "initial": "none",
+      "appliesTo": "non-replaced inline elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified keyword, plus integer if digits",
+      "canonicalOrder": "n/a",
+      "animationType": "not animatable"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/cssom-view.json b/w3c/css/cssom-view.json
new file mode 100644
index 000000000000..86baa507ff11
--- /dev/null
+++ b/w3c/css/cssom-view.json
@@ -0,0 +1,17 @@
+{
+  "properties": {
+    "scroll-behavior": {
+      "name": "scroll-behavior",
+      "value": "auto | smooth",
+      "initial": "auto",
+      "appliesTo": "scrolling boxes",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/fill-stroke.json b/w3c/css/fill-stroke.json
new file mode 100644
index 000000000000..5a96b1940e23
--- /dev/null
+++ b/w3c/css/fill-stroke.json
@@ -0,0 +1,352 @@
+{
+  "properties": {
+    "fill-rule": {
+      "name": "fill-rule",
+      "value": "nonzero | evenodd",
+      "initial": "nonzero",
+      "appliesTo": "SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "fill-break": {
+      "name": "fill-break",
+      "value": "bounding-box | slice | clone",
+      "initial": "bounding-box",
+      "appliesTo": "all elements",
+      "inherited": "yes?",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "No"
+    },
+    "fill-color": {
+      "name": "fill-color",
+      "value": "<color>",
+      "initial": "currentcolor",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "the computed color",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as color"
+    },
+    "fill-image": {
+      "name": "fill-image",
+      "value": "<paint>#",
+      "initial": "none",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified, with URLs made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of images"
+    },
+    "fill-origin": {
+      "name": "fill-origin",
+      "value": "match-parent | fill-box | stroke-box | content-box | padding-box | border-box",
+      "initial": "match-parent",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "fill-position": {
+      "name": "fill-position",
+      "value": "<position>#",
+      "initial": "0% 0%",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "A list, each item consisting of: a pair of offsets (horizontal and vertical) from the top left origin each given as a combination of an absolute length and a percentage",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of simple list of length, percentage, or calc"
+    },
+    "fill-size": {
+      "name": "fill-size",
+      "value": "<bg-size>#",
+      "initial": "auto",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified, but with lengths made absolute and omitted auto keywords filled in",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of simple list of length, percentage, or calc"
+    },
+    "fill-repeat": {
+      "name": "fill-repeat",
+      "value": "<repeat-style>#",
+      "initial": "repeat",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "A list, each item consisting of: two keywords, one per dimension",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "fill": {
+      "name": "fill",
+      "value": "<‘background’> with modifications",
+      "initial": "See individual properties",
+      "appliesTo": "See individual properties",
+      "inherited": "See individual properties",
+      "percentages": "N/A",
+      "computedValue": "See individual properties",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "See individual properties"
+    },
+    "fill-opacity": {
+      "name": "fill-opacity",
+      "value": "<‘opacity’>",
+      "initial": "1",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "the specified value converted to a <number>, clamped to the range [0,1]",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as number"
+    },
+    "stroke-width": {
+      "name": "stroke-width",
+      "value": "<length-percentage>#",
+      "initial": "1px",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "relative to the scaled viewport size",
+      "computedValue": "the absolute length, or percentage",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as <length-percentage>"
+    },
+    "stroke-align": {
+      "name": "stroke-align",
+      "value": "center | inset | outset",
+      "initial": "center",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "stroke-linecap": {
+      "name": "stroke-linecap",
+      "value": "butt | round | square",
+      "initial": "butt",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "stroke-linejoin": {
+      "name": "stroke-linejoin",
+      "value": "[ crop | arcs | miter ] || [ bevel | round | stupid ]",
+      "initial": "miter",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "stroke-miterlimit": {
+      "name": "stroke-miterlimit",
+      "value": "<number>",
+      "initial": "4",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "a number",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "stroke-break": {
+      "name": "stroke-break",
+      "value": "bounding-box | slice | clone",
+      "initial": "bounding-box",
+      "appliesTo": "all elements",
+      "inherited": "?",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "No"
+    },
+    "stroke-dasharray": {
+      "name": "stroke-dasharray",
+      "value": "none | <length-percentage>+#",
+      "initial": "none",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "relative to the scaled viewport size",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeated list of length, percentage or calc"
+    },
+    "stroke-dashoffset": {
+      "name": "stroke-dashoffset",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "relative to the scaled viewport size",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeated list of integers"
+    },
+    "stroke-dash-corner": {
+      "name": "stroke-dash-corner",
+      "value": "none | <length>",
+      "initial": "none",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "specified value, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "yes, if <length>"
+    },
+    "stroke-dash-justify": {
+      "name": "stroke-dash-justify",
+      "value": "none | [ stretch | compress ] || [ dashes || gaps ]",
+      "initial": "none",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "specified value, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "stroke-color": {
+      "name": "stroke-color",
+      "value": "<color>#",
+      "initial": "transparent",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "the computed color",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as color"
+    },
+    "stroke-image": {
+      "name": "stroke-image",
+      "value": "<paint>#",
+      "initial": "none",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified, with URLs made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of images"
+    },
+    "stroke-origin": {
+      "name": "stroke-origin",
+      "value": "match-parent | fill-box | stroke-box | content-box | padding-box | border-box",
+      "initial": "match-parent",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "stroke-position": {
+      "name": "stroke-position",
+      "value": "<position>#",
+      "initial": "0% 0%",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "A list, each item consisting of: a pair of offsets (horizontal and vertical) from the top left origin each given as a combination of an absolute length and a percentage",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of simple list of length, percentage, or calc"
+    },
+    "stroke-size": {
+      "name": "stroke-size",
+      "value": "<bg-size>#",
+      "initial": "auto",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified, but with lengths made absolute and omitted auto keywords filled in",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of simple list of length, percentage, or calc"
+    },
+    "stroke-repeat": {
+      "name": "stroke-repeat",
+      "value": "<repeat-style>#",
+      "initial": "repeat",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "A list, each item consisting of: two keywords, one per dimension",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "stroke": {
+      "name": "stroke",
+      "value": "<‘background’> with modifications",
+      "initial": "See individual properties",
+      "appliesTo": "See individual properties",
+      "inherited": "See individual properties",
+      "percentages": "N/A",
+      "computedValue": "See individual properties",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "See individual properties"
+    },
+    "stroke-opacity": {
+      "name": "stroke-opacity",
+      "value": "<‘opacity’>",
+      "initial": "1",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "the specified value converted to a <number>, clamped to the range [0,1]",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as number"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<paint>": {
+      "value": "none | <image> | <svg-paint>"
+    },
+    "<svg-paint>": {
+      "value": "child | child( <integer> )"
+    },
+    "<child()>": {
+      "value": "child(<integer>)"
+    }
+  }
+}
diff --git a/w3c/css/filter-effects.json b/w3c/css/filter-effects.json
new file mode 100644
index 000000000000..e5d1a8e4b9f6
--- /dev/null
+++ b/w3c/css/filter-effects.json
@@ -0,0 +1,18 @@
+{
+  "properties": {
+    "backdrop-filter": {
+      "name": "backdrop-filter",
+      "value": "none | <filter-function-list>",
+      "initial": "none",
+      "appliesTo": "All elements. In SVG, it applies to container elements without the defs element and all graphics elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "yes"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/mediaqueries.json b/w3c/css/mediaqueries.json
new file mode 100644
index 000000000000..a241e3bdb548
--- /dev/null
+++ b/w3c/css/mediaqueries.json
@@ -0,0 +1,54 @@
+{
+  "properties": {},
+  "descriptors": {
+    "light-level": {
+      "name": "light-level",
+      "for": "@media",
+      "value": "dim | normal | washed",
+      "type": "discrete"
+    },
+    "environment-blending": {
+      "name": "environment-blending",
+      "for": "@media",
+      "value": "opaque | additive | subtractive",
+      "type": "discrete"
+    },
+    "scripting": {
+      "name": "scripting",
+      "for": "@media",
+      "value": "none | initial-only | enabled",
+      "type": "discrete"
+    },
+    "inverted-colors": {
+      "name": "inverted-colors",
+      "for": "@media",
+      "value": "none | inverted",
+      "type": "discrete"
+    },
+    "prefers-reduced-motion": {
+      "name": "prefers-reduced-motion",
+      "for": "@media",
+      "value": "no-preference | reduce",
+      "type": "discrete"
+    },
+    "prefers-reduced-transparency": {
+      "name": "prefers-reduced-transparency",
+      "for": "@media",
+      "value": "no-preference | reduce",
+      "type": "discrete"
+    },
+    "prefers-contrast": {
+      "name": "prefers-contrast",
+      "for": "@media",
+      "value": "no-preference | high | low",
+      "type": "discrete"
+    },
+    "prefers-color-scheme": {
+      "name": "prefers-color-scheme",
+      "for": "@media",
+      "value": "no-preference | light | dark",
+      "type": "discrete"
+    }
+  },
+  "valuespaces": {}
+}
diff --git a/w3c/css/motion.json b/w3c/css/motion.json
new file mode 100644
index 000000000000..be152257a5e8
--- /dev/null
+++ b/w3c/css/motion.json
@@ -0,0 +1,88 @@
+{
+  "properties": {
+    "offset-path": {
+      "name": "offset-path",
+      "value": "none | ray() | path() | <url> | [ <basic-shape> || <geometry-box> ]",
+      "initial": "none",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as <angle>, <basic-shape> or path()"
+    },
+    "offset-distance": {
+      "name": "offset-distance",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "refer to the total path length",
+      "computedValue": "For <length> the absolute value, otherwise a percentage.",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "yes"
+    },
+    "offset-position": {
+      "name": "offset-position",
+      "value": "auto | <position>",
+      "initial": "auto",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "Refer to the size of containing block",
+      "computedValue": "For <length> the absolute value, otherwise a percentage.",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as position"
+    },
+    "offset-anchor": {
+      "name": "offset-anchor",
+      "value": "auto | <position>",
+      "initial": "auto",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "Relative to the width and the height of a box",
+      "computedValue": "For <length> the absolute value, otherwise a percentage.",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as <position>"
+    },
+    "offset-rotate": {
+      "name": "offset-rotate",
+      "value": "[ auto | reverse ] || <angle>",
+      "initial": "auto",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "yes"
+    },
+    "offset": {
+      "name": "offset",
+      "value": "[ offset-position? [ offset-path [ offset-distance || offset-rotate ]? ]? ]! [ / offset-anchor ]?",
+      "initial": "see individual properties",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "see individual properties"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<ray()>": {
+      "value": "ray( [ <angle> && <size> && contain? ] )"
+    },
+    "<path()>": {
+      "value": "path(<string>)"
+    },
+    "<size>": {
+      "prose": "Decides the path length used when offset-distance is expressed as a percentage, using the distance to the containing box. For <size> values other than sides, the path length is independent of <angle>. It is defined as <size> = [ closest-side | closest-corner | farthest-side | farthest-corner | sides ] closest-side The perpendicular distance is measured between the initial position and the closest side of the box from it. closest-corner The distance is measured between the initial position and the closest corner of the box from it. farthest-side The perpendicular distance is measured between the initial position and the farthest side of the box from it. farthest-corner The distance is measured between the initial position and the farthest corner of the box from it. sides The distance is measured between the initial position and the intersection of the ray with the box. If the initial position is not within the box, the distance is 0. Note: When the initial position is on one of the edges of the containing block, the closest side takes the edge that the initial position is on, and thus the path length used for percentage offset-distance values is 0. Note: When closest-side or farthest-side are used, and the initial position is outside the box, the sides are considered to extend indefinitely."
+    }
+  }
+}
diff --git a/w3c/css/overscroll-behavior.json b/w3c/css/overscroll-behavior.json
new file mode 100644
index 000000000000..3cd6381d5bef
--- /dev/null
+++ b/w3c/css/overscroll-behavior.json
@@ -0,0 +1,42 @@
+{
+  "properties": {
+    "overscroll-behavior-x": {
+      "name": "overscroll-behavior-x",
+      "value": "contain | none | auto",
+      "initial": "auto",
+      "appliesTo": "scroll container elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "overscroll-behavior-y": {
+      "name": "overscroll-behavior-y",
+      "value": "contain | none | auto",
+      "initial": "auto",
+      "appliesTo": "scroll container elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "overscroll-behavior": {
+      "name": "overscroll-behavior",
+      "value": "[ contain | none | auto ]{1,2}",
+      "initial": "auto auto",
+      "appliesTo": "scroll container elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "media": "visual",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/w3c/css/scroll-animations.json b/w3c/css/scroll-animations.json
new file mode 100644
index 000000000000..5284f5b3ec00
--- /dev/null
+++ b/w3c/css/scroll-animations.json
@@ -0,0 +1,28 @@
+{
+  "properties": {
+    "animation-timeline": {
+      "name": "animation-timeline",
+      "value": "<single-animation-timeline>#",
+      "initial": "auto",
+      "appliesTo": "all elements, ::before and ::after pseudo-elements",
+      "inherited": "none",
+      "percentages": "N/A",
+      "media": "interactive",
+      "computedValue": "As specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<single-animation-timeline>": {
+      "value": "auto | scroll([element(<id-selector>)[, <scroll-direction>[, <scroll-offset>[, <scroll-offset>[, <time>[, <single-animation-fill-mode>]]]]]])"
+    },
+    "<scroll-direction>": {
+      "value": "auto | block | inline | horizontal | vertical"
+    },
+    "<scroll-offset>": {
+      "value": "<length> | <percentage> | auto"
+    }
+  }
+}
diff --git a/w3c/css/selectors-nonelement.json b/w3c/css/selectors-nonelement.json
new file mode 100644
index 000000000000..8a4ce2c08d88
--- /dev/null
+++ b/w3c/css/selectors-nonelement.json
@@ -0,0 +1,18 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<::attr()>": {
+      "value": "::attr( <namespace-attr>? )"
+    },
+    "<namespace-attr>": {
+      "value": "[ <na-prefix>? '|' ]? <na-name>"
+    },
+    "<na-prefix>": {
+      "value": "<ident> | '*'"
+    },
+    "<na-name>": {
+      "value": "<ident> | '*'"
+    }
+  }
+}
diff --git a/w3c/css/selectors.json b/w3c/css/selectors.json
new file mode 100644
index 000000000000..972d13708c68
--- /dev/null
+++ b/w3c/css/selectors.json
@@ -0,0 +1,69 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<selector-list>": {
+      "value": "<complex-selector-list>"
+    },
+    "<complex-selector-list>": {
+      "value": "<complex-selector>#"
+    },
+    "<compound-selector-list>": {
+      "value": "<compound-selector>#"
+    },
+    "<simple-selector-list>": {
+      "value": "<simple-selector>#"
+    },
+    "<relative-selector-list>": {
+      "value": "<relative-selector>#"
+    },
+    "<complex-selector>": {
+      "value": "<compound-selector> [ <combinator>? <compound-selector> ]*"
+    },
+    "<relative-selector>": {
+      "value": "<combinator>? <complex-selector>"
+    },
+    "<compound-selector>": {
+      "value": "[ <type-selector>? <subclass-selector>* [ <pseudo-element-selector> <pseudo-class-selector>* ]* ]!"
+    },
+    "<simple-selector>": {
+      "value": "<type-selector> | <subclass-selector>"
+    },
+    "<combinator>": {
+      "value": "'>' | '+' | '~' | [ '||' ]"
+    },
+    "<type-selector>": {
+      "value": "<wq-name> | <ns-prefix>? '*'"
+    },
+    "<ns-prefix>": {
+      "value": "[ <ident-token> | '*' ]? '|'"
+    },
+    "<wq-name>": {
+      "value": "<ns-prefix>? <ident-token>"
+    },
+    "<subclass-selector>": {
+      "value": "<id-selector> | <class-selector> | <attribute-selector> | <pseudo-class-selector>"
+    },
+    "<id-selector>": {
+      "value": "<hash-token>"
+    },
+    "<class-selector>": {
+      "value": "'.' <ident-token>"
+    },
+    "<attribute-selector>": {
+      "value": "'[' <wq-name> ']' | '[' <wq-name> <attr-matcher> [ <string-token> | <ident-token> ] <attr-modifier>? ']'"
+    },
+    "<attr-matcher>": {
+      "value": "[ '~' | '|' | '^' | '$' | '*' ]? '='"
+    },
+    "<attr-modifier>": {
+      "value": "i"
+    },
+    "<pseudo-class-selector>": {
+      "value": "':' <ident-token> | ':' <function-token> <any-value> ')'"
+    },
+    "<pseudo-element-selector>": {
+      "value": "':' <pseudo-class-selector>"
+    }
+  }
+}
diff --git a/w3c/css/svg-markers.json b/w3c/css/svg-markers.json
new file mode 100644
index 000000000000..9817fd021efb
--- /dev/null
+++ b/w3c/css/svg-markers.json
@@ -0,0 +1,113 @@
+{
+  "properties": {
+    "marker-start": {
+      "name": "marker-start",
+      "value": "none | <marker-ref>",
+      "initial": "none",
+      "appliesTo": "shape elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker-mid": {
+      "name": "marker-mid",
+      "value": "none | <marker-ref>",
+      "initial": "none",
+      "appliesTo": "shape elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker-end": {
+      "name": "marker-end",
+      "value": "none | <marker-ref>",
+      "initial": "none",
+      "appliesTo": "shape elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker-segment": {
+      "name": "marker-segment",
+      "value": "none | <marker-ref>",
+      "initial": "none",
+      "appliesTo": "shape elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker-pattern": {
+      "name": "marker-pattern",
+      "value": "<marker-gap>? <marker-ref-group> [ <marker-gap> <marker-ref-group> ]* <marker-gap>?",
+      "initial": "none",
+      "appliesTo": "shape elements",
+      "inherited": "yes",
+      "percentages": "refer to the length of the path",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker": {
+      "name": "marker",
+      "value": "[ none | <marker-ref> ]{1,4} [ / <‘marker-pattern’> ]? | <marker-ref>{0,4} [ <length> | <percentage> | <number> ] [ <length> | <percentage> | <number> | <marker-ref> ]*",
+      "initial": "not defined for shorthand properties",
+      "appliesTo": "shape elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties",
+      "animatable": "yes"
+    },
+    "marker-knockout-left": {
+      "name": "marker-knockout-left",
+      "value": "<knockout-offset> | <knockout-shape> [ at <knockout-offset> ]?",
+      "initial": "0",
+      "appliesTo": "‘marker’",
+      "inherited": "no",
+      "percentages": "see prose",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "marker-knockout-right": {
+      "name": "marker-knockout-right",
+      "value": "<knockout-offset> | <knockout-shape> [ at <knockout-offset> ]?",
+      "initial": "0",
+      "appliesTo": "‘marker’",
+      "inherited": "no",
+      "percentages": "see prose",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<marker-ref>": {
+      "value": "<url> | child | <child-selector>"
+    },
+    "<child-selector>": {
+      "value": "select(compound selector#)"
+    },
+    "<marker-gap>": {
+      "value": "<length> | <percentage> | <number>"
+    },
+    "<marker-ref-group>": {
+      "value": "none | <marker-ref>+"
+    },
+    "<knockout-offset>": {
+      "value": "[ <length> | <percentage> | <number> ]"
+    },
+    "<knockout-shape>": {
+      "value": "[ <length> | <percentage> | <number> ] inverted? circle | [ <length> | <percentage> | <number> ]{2} inverted? ellipse | [ <length> | <percentage> | <number> ]{1,2} inverted? [ rectangle | triangle ]"
+    }
+  }
+}
diff --git a/w3c/css/svg-strokes.json b/w3c/css/svg-strokes.json
new file mode 100644
index 000000000000..d7af8c5fa8c1
--- /dev/null
+++ b/w3c/css/svg-strokes.json
@@ -0,0 +1,131 @@
+{
+  "properties": {
+    "stroke": {
+      "name": "stroke",
+      "value": "<paint>",
+      "initial": "none",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <color> values computed and <url> values made absolute",
+      "animatable": "yes"
+    },
+    "stroke-alignment": {
+      "name": "stroke-alignment",
+      "value": "center | inner | outer",
+      "initial": "center",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "stroke-opacity": {
+      "name": "stroke-opacity",
+      "value": "<number>",
+      "initial": "1",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but clamped to the range [0, 1]",
+      "animatable": "yes"
+    },
+    "stroke-width": {
+      "name": "stroke-width",
+      "value": "<percentage> | <length>",
+      "initial": "1",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "refer to the size of the current viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "stroke-linecap": {
+      "name": "stroke-linecap",
+      "value": "butt | round | square",
+      "initial": "butt",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "stroke-linejoin": {
+      "name": "stroke-linejoin",
+      "value": "miter | miter-clip | round | bevel | arcs",
+      "initial": "miter",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "stroke-miterlimit": {
+      "name": "stroke-miterlimit",
+      "value": "<number>",
+      "initial": "4",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "stroke-dasharray": {
+      "name": "stroke-dasharray",
+      "value": "none | <dasharray>",
+      "initial": "none",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "refer to the size of the current viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute lengths or percentages for <dasharray>, or keyword specified",
+      "animatable": "yes (non-additive)"
+    },
+    "stroke-dashoffset": {
+      "name": "stroke-dashoffset",
+      "value": "<length> | <percentage>",
+      "initial": "0",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "refer to the size of the current viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "stroke-dashcorner": {
+      "name": "stroke-dashcorner",
+      "value": "none | <length>",
+      "initial": "none",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "refer to the size of the current viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute length or keyword specified",
+      "animatable": "yes"
+    },
+    "stroke-dashadjust": {
+      "name": "stroke-dashadjust",
+      "value": "none | [stretch | compress] [dashes | gaps]?",
+      "initial": "none",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<dasharray>": {
+      "value": "[ <length> | <percentage> | <number> ]#*"
+    }
+  }
+}
diff --git a/whatwg/css/CSS.json b/whatwg/css/CSS.json
new file mode 100644
index 000000000000..dfc0faf3f6cf
--- /dev/null
+++ b/whatwg/css/CSS.json
@@ -0,0 +1,1156 @@
+{
+  "properties": {
+    "margin-top": {
+      "name": "margin-top",
+      "value": "<margin-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except elements with table display types other than table-caption, table and inline-table",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "margin-bottom": {
+      "name": "margin-bottom",
+      "value": "<margin-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except elements with table display types other than table-caption, table and inline-table",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "margin-right": {
+      "name": "margin-right",
+      "value": "<margin-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except elements with table display types other than table-caption, table and inline-table",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "margin-left": {
+      "name": "margin-left",
+      "value": "<margin-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except elements with table display types other than table-caption, table and inline-table",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "margin": {
+      "name": "margin",
+      "value": "<margin-width>{1,4} | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements except elements with table display types other than table-caption, table and inline-table",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "padding-top": {
+      "name": "padding-top",
+      "value": "<padding-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except table-row-group, table-header-group, table-footer-group, table-row, table-column-group and table-column",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "padding-right": {
+      "name": "padding-right",
+      "value": "<padding-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except table-row-group, table-header-group, table-footer-group, table-row, table-column-group and table-column",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "padding-bottom": {
+      "name": "padding-bottom",
+      "value": "<padding-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except table-row-group, table-header-group, table-footer-group, table-row, table-column-group and table-column",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "padding-left": {
+      "name": "padding-left",
+      "value": "<padding-width> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements except table-row-group, table-header-group, table-footer-group, table-row, table-column-group and table-column",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "padding": {
+      "name": "padding",
+      "value": "<padding-width>{1,4} | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements except table-row-group, table-header-group, table-footer-group, table-row, table-column-group and table-column",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border-top-width": {
+      "name": "border-top-width",
+      "value": "<border-width> | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "absolute length; '0' if the border style is 'none' or 'hidden'"
+    },
+    "border-right-width": {
+      "name": "border-right-width",
+      "value": "<border-width> | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "absolute length; '0' if the border style is 'none' or 'hidden'"
+    },
+    "border-bottom-width": {
+      "name": "border-bottom-width",
+      "value": "<border-width> | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "absolute length; '0' if the border style is 'none' or 'hidden'"
+    },
+    "border-left-width": {
+      "name": "border-left-width",
+      "value": "<border-width> | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "absolute length; '0' if the border style is 'none' or 'hidden'"
+    },
+    "border-width": {
+      "name": "border-width",
+      "value": "<border-width>{1,4} | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border-top-color": {
+      "name": "border-top-color",
+      "value": "<color> | transparent | inherit",
+      "initial": "the value of the 'color' property",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "when taken from the 'color' property, the computed value of 'color'; otherwise, as specified"
+    },
+    "border-right-color": {
+      "name": "border-right-color",
+      "value": "<color> | transparent | inherit",
+      "initial": "the value of the 'color' property",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "when taken from the 'color' property, the computed value of 'color'; otherwise, as specified"
+    },
+    "border-bottom-color": {
+      "name": "border-bottom-color",
+      "value": "<color> | transparent | inherit",
+      "initial": "the value of the 'color' property",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "when taken from the 'color' property, the computed value of 'color'; otherwise, as specified"
+    },
+    "border-left-color": {
+      "name": "border-left-color",
+      "value": "<color> | transparent | inherit",
+      "initial": "the value of the 'color' property",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "when taken from the 'color' property, the computed value of 'color'; otherwise, as specified"
+    },
+    "border-color": {
+      "name": "border-color",
+      "value": "[ <color> | transparent ]{1,4} | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border-top-style": {
+      "name": "border-top-style",
+      "value": "<border-style> | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "border-right-style": {
+      "name": "border-right-style",
+      "value": "<border-style> | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "border-bottom-style": {
+      "name": "border-bottom-style",
+      "value": "<border-style> | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "border-left-style": {
+      "name": "border-left-style",
+      "value": "<border-style> | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "border-style": {
+      "name": "border-style",
+      "value": "<border-style>{1,4} | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border-top": {
+      "name": "border-top",
+      "value": "[ <border-width> || <border-style> || <'border-top-color'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border-right": {
+      "name": "border-right",
+      "value": "[ <border-width> || <border-style> || <'border-top-color'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border-bottom": {
+      "name": "border-bottom",
+      "value": "[ <border-width> || <border-style> || <'border-top-color'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border-left": {
+      "name": "border-left",
+      "value": "[ <border-width> || <border-style> || <'border-top-color'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "border": {
+      "name": "border",
+      "value": "[ <border-width> || <border-style> || <'border-top-color'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "display": {
+      "name": "display",
+      "value": "inline | block | list-item | inline-block | table | inline-table | table-row-group | table-header-group | table-footer-group | table-row | table-column-group | table-column | table-cell | table-caption | none | inherit",
+      "initial": "inline",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "all",
+      "computed value": "see text"
+    },
+    "position": {
+      "name": "position",
+      "value": "static | relative | absolute | fixed | inherit",
+      "initial": "static",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "top": {
+      "name": "top",
+      "value": "<length> | <percentage> | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "media": "visual",
+      "computed value": "if specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, 'auto'."
+    },
+    "right": {
+      "name": "right",
+      "value": "<length> | <percentage> | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "if specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, 'auto'."
+    },
+    "bottom": {
+      "name": "bottom",
+      "value": "<length> | <percentage> | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "media": "visual",
+      "computed value": "if specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, 'auto'."
+    },
+    "left": {
+      "name": "left",
+      "value": "<length> | <percentage> | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "if specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, 'auto'."
+    },
+    "float": {
+      "name": "float",
+      "value": "left | right | none | inherit",
+      "initial": "none",
+      "appliesTo": "all, but see 9.7",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "clear": {
+      "name": "clear",
+      "value": "none | left | right | both | inherit",
+      "initial": "none",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "z-index": {
+      "name": "z-index",
+      "value": "auto | <integer> | inherit",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "direction": {
+      "name": "direction",
+      "value": "ltr | rtl | inherit",
+      "initial": "ltr",
+      "appliesTo": "all elements, but see prose",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "unicode-bidi": {
+      "name": "unicode-bidi",
+      "value": "normal | embed | bidi-override | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements, but see prose",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "width": {
+      "name": "width",
+      "value": "<length> | <percentage> | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "all elements but non-replaced inline elements, table rows, and row groups",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage or 'auto' as specified or the absolute length"
+    },
+    "min-width": {
+      "name": "min-width",
+      "value": "<length> | <percentage> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements but non-replaced inline elements, table rows, and row groups",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "max-width": {
+      "name": "max-width",
+      "value": "<length> | <percentage> | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements but non-replaced inline elements, table rows, and row groups",
+      "inherited": "no",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length or 'none'"
+    },
+    "height": {
+      "name": "height",
+      "value": "<length> | <percentage> | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "all elements but non-replaced inline elements, table columns, and column groups",
+      "inherited": "no",
+      "percentages": "see prose",
+      "media": "visual",
+      "computed value": "the percentage or 'auto' (see prose under <percentage>) or the absolute length"
+    },
+    "min-height": {
+      "name": "min-height",
+      "value": "<length> | <percentage> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements but non-replaced inline elements, table columns, and column groups",
+      "inherited": "no",
+      "percentages": "see prose",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "max-height": {
+      "name": "max-height",
+      "value": "<length> | <percentage> | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements but non-replaced inline elements, table columns, and column groups",
+      "inherited": "no",
+      "percentages": "see prose",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length or 'none'"
+    },
+    "line-height": {
+      "name": "line-height",
+      "value": "normal | <number> | <length> | <percentage> | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "refer to the font size of the element itself",
+      "media": "visual",
+      "computed value": "for <length> and <percentage> the absolute value; otherwise as specified"
+    },
+    "vertical-align": {
+      "name": "vertical-align",
+      "value": "baseline | sub | super | top | text-top | middle | bottom | text-bottom | <percentage> | <length> | inherit",
+      "initial": "baseline",
+      "appliesTo": "inline-level and 'table-cell' elements",
+      "inherited": "no",
+      "percentages": "refer to the 'line-height' of the element itself",
+      "media": "visual",
+      "computed value": "for <percentage> and <length> the absolute length, otherwise as specified"
+    },
+    "overflow": {
+      "name": "overflow",
+      "value": "visible | hidden | scroll | auto | inherit",
+      "initial": "visible",
+      "appliesTo": "block containers",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "clip": {
+      "name": "clip",
+      "value": "<shape> | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "absolutely positioned elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "'auto' if specified as 'auto', otherwise a rectangle with four values, each of which is 'auto' if specified as 'auto' and the computed length otherwise"
+    },
+    "visibility": {
+      "name": "visibility",
+      "value": "visible | hidden | collapse | inherit",
+      "initial": "visible",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "content": {
+      "name": "content",
+      "value": "normal | none | [ <string> | <uri> | <counter> | attr(<identifier>) | open-quote | close-quote | no-open-quote | no-close-quote ]+ | inherit",
+      "initial": "normal",
+      "appliesTo": ":before and :after pseudo-elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "all",
+      "computed value": "On elements, always computes to 'normal'. On :before and :after, if 'normal' is specified, computes to 'none'. Otherwise, for URI values, the absolute URI; for attr() values, the resulting string; for other keywords, as specified."
+    },
+    "quotes": {
+      "name": "quotes",
+      "value": "[<string> <string>]+ | none | inherit",
+      "initial": "depends on user agent",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "counter-reset": {
+      "name": "counter-reset",
+      "value": "[ <identifier> <integer>? ]+ | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "all",
+      "computed value": "as specified"
+    },
+    "counter-increment": {
+      "name": "counter-increment",
+      "value": "[ <identifier> <integer>? ]+ | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "all",
+      "computed value": "as specified"
+    },
+    "list-style-type": {
+      "name": "list-style-type",
+      "value": "disc | circle | square | decimal | decimal-leading-zero | lower-roman | upper-roman | lower-greek | lower-latin | upper-latin | armenian | georgian | lower-alpha | upper-alpha | none | inherit",
+      "initial": "disc",
+      "appliesTo": "elements with 'display: list-item'",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "list-style-image": {
+      "name": "list-style-image",
+      "value": "<uri> | none | inherit",
+      "initial": "none",
+      "appliesTo": "elements with 'display: list-item'",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "absolute URI or 'none'"
+    },
+    "list-style-position": {
+      "name": "list-style-position",
+      "value": "inside | outside | inherit",
+      "initial": "outside",
+      "appliesTo": "elements with 'display: list-item'",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "list-style": {
+      "name": "list-style",
+      "value": "[ <'list-style-type'> || <'list-style-position'> || <'list-style-image'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "elements with 'display: list-item'",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "page-break-before": {
+      "name": "page-break-before",
+      "value": "auto | always | avoid | left | right | inherit",
+      "initial": "auto",
+      "appliesTo": "block-level elements (but see text)",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual, paged",
+      "computed value": "as specified"
+    },
+    "page-break-after": {
+      "name": "page-break-after",
+      "value": "auto | always | avoid | left | right | inherit",
+      "initial": "auto",
+      "appliesTo": "block-level elements (but see text)",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual, paged",
+      "computed value": "as specified"
+    },
+    "page-break-inside": {
+      "name": "page-break-inside",
+      "value": "avoid | auto | inherit",
+      "initial": "auto",
+      "appliesTo": "block-level elements (but see text)",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual, paged",
+      "computed value": "as specified"
+    },
+    "orphans": {
+      "name": "orphans",
+      "value": "<integer> | inherit",
+      "initial": "2",
+      "appliesTo": "block container elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual, paged",
+      "computed value": "as specified"
+    },
+    "widows": {
+      "name": "widows",
+      "value": "<integer> | inherit",
+      "initial": "2",
+      "appliesTo": "block container elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual, paged",
+      "computed value": "as specified"
+    },
+    "color": {
+      "name": "color",
+      "value": "<color> | inherit",
+      "initial": "depends on user agent",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "background-color": {
+      "name": "background-color",
+      "value": "<color> | transparent | inherit",
+      "initial": "transparent",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "background-image": {
+      "name": "background-image",
+      "value": "<uri> | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "absolute URI or none"
+    },
+    "background-repeat": {
+      "name": "background-repeat",
+      "value": "repeat | repeat-x | repeat-y | no-repeat | inherit",
+      "initial": "repeat",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "background-attachment": {
+      "name": "background-attachment",
+      "value": "scroll | fixed | inherit",
+      "initial": "scroll",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "background-position": {
+      "name": "background-position",
+      "value": "[ [ <percentage> | <length> | left | center | right ] [ <percentage> | <length> | top | center | bottom ]? ] | [ [ left | center | right ] || [ top | center | bottom ] ] | inherit",
+      "initial": "0% 0%",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to the size of the box itself",
+      "media": "visual",
+      "computed value": "for <length> the absolute value, otherwise a percentage"
+    },
+    "background": {
+      "name": "background",
+      "value": "[<'background-color'> || <'background-image'> || <'background-repeat'> || <'background-attachment'> || <'background-position'>] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "allowed on 'background-position'",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "font-family": {
+      "name": "font-family",
+      "value": "[[ <family-name> | <generic-family> ] [, <family-name>| <generic-family>]* ] | inherit",
+      "initial": "depends on user agent",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "font-style": {
+      "name": "font-style",
+      "value": "normal | italic | oblique | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "font-variant": {
+      "name": "font-variant",
+      "value": "normal | small-caps | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "font-weight": {
+      "name": "font-weight",
+      "value": "normal | bold | bolder | lighter | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see text"
+    },
+    "font-size": {
+      "name": "font-size",
+      "value": "<absolute-size> | <relative-size> | <length> | <percentage> | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "refer to inherited font size",
+      "media": "visual",
+      "computed value": "absolute length"
+    },
+    "font": {
+      "name": "font",
+      "value": "[ [ <'font-style'> || <'font-variant'> || <'font-weight'> ]? <'font-size'> [ / <'line-height'> ]? <'font-family'> ] | caption | icon | menu | message-box | small-caption | status-bar | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "see individual properties",
+      "media": "visual",
+      "computed value": "see individual properties"
+    },
+    "text-indent": {
+      "name": "text-indent",
+      "value": "<length> | <percentage> | inherit",
+      "initial": "0",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "refer to width of containing block",
+      "media": "visual",
+      "computed value": "the percentage as specified or the absolute length"
+    },
+    "text-align": {
+      "name": "text-align",
+      "value": "left | right | center | justify | inherit",
+      "initial": "a nameless value that acts as 'left' if 'direction' is 'ltr', 'right' if 'direction' is 'rtl'",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "the initial value or as specified"
+    },
+    "text-decoration": {
+      "name": "text-decoration",
+      "value": "none | [ underline || overline || line-through || blink ] | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no (see prose)",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "letter-spacing": {
+      "name": "letter-spacing",
+      "value": "normal | <length> | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "'normal' or absolute length"
+    },
+    "word-spacing": {
+      "name": "word-spacing",
+      "value": "normal | <length> | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "for 'normal' the value '0'; otherwise the absolute length"
+    },
+    "text-transform": {
+      "name": "text-transform",
+      "value": "capitalize | uppercase | lowercase | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "white-space": {
+      "name": "white-space",
+      "value": "normal | pre | nowrap | pre-wrap | pre-line | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "caption-side": {
+      "name": "caption-side",
+      "value": "top | bottom | inherit",
+      "initial": "top",
+      "appliesTo": "'table-caption' elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "table-layout": {
+      "name": "table-layout",
+      "value": "auto | fixed | inherit",
+      "initial": "auto",
+      "appliesTo": "'table' and 'inline-table' elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "border-collapse": {
+      "name": "border-collapse",
+      "value": "collapse | separate | inherit",
+      "initial": "separate",
+      "appliesTo": "'table' and 'inline-table' elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "border-spacing": {
+      "name": "border-spacing",
+      "value": "<length> <length>? | inherit",
+      "initial": "0",
+      "appliesTo": "'table' and 'inline-table' elements*",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "two absolute lengths"
+    },
+    "empty-cells": {
+      "name": "empty-cells",
+      "value": "show | hide | inherit",
+      "initial": "show",
+      "appliesTo": "'table-cell' elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified"
+    },
+    "cursor": {
+      "name": "cursor",
+      "value": "[ [<uri> ,]* [ auto | crosshair | default | pointer | move | e-resize | ne-resize | nw-resize | n-resize | se-resize | sw-resize | s-resize | w-resize | text | wait | help | progress ] ] | inherit",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual, interactive",
+      "computed value": "as specified, except with any relative URLs converted to absolute"
+    },
+    "outline": {
+      "name": "outline",
+      "value": "[ <'outline-color'> || <'outline-style'> || <'outline-width'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual, interactive",
+      "computed value": "see individual properties"
+    },
+    "outline-width": {
+      "name": "outline-width",
+      "value": "<border-width> | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual, interactive",
+      "computed value": "absolute length; '0' if the outline style is 'none'"
+    },
+    "outline-style": {
+      "name": "outline-style",
+      "value": "<border-style> | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual, interactive",
+      "computed value": "as specified"
+    },
+    "outline-color": {
+      "name": "outline-color",
+      "value": "<color> | invert | inherit",
+      "initial": "invert",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual, interactive",
+      "computed value": "as specified"
+    },
+    "volume": {
+      "name": "volume",
+      "value": "<number> | <percentage> | silent | x-soft | soft | medium | loud | x-loud | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "refer to inherited value",
+      "media": "aural",
+      "computed value": "number"
+    },
+    "speak": {
+      "name": "speak",
+      "value": "normal | none | spell-out | inherit",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    },
+    "pause-before": {
+      "name": "pause-before",
+      "value": "<time> | <percentage> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "see prose",
+      "media": "aural",
+      "computed value": "time"
+    },
+    "pause-after": {
+      "name": "pause-after",
+      "value": "<time> | <percentage> | inherit",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "see prose",
+      "media": "aural",
+      "computed value": "time;;"
+    },
+    "pause": {
+      "name": "pause",
+      "value": "[ [<time> | <percentage>]{1,2} ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "see descriptions of 'pause-before' and 'pause-after'",
+      "media": "aural",
+      "computed value": "see individual properties"
+    },
+    "cue-before": {
+      "name": "cue-before",
+      "value": "<uri> | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "absolute URI or 'none'"
+    },
+    "cue-after": {
+      "name": "cue-after",
+      "value": "<uri> | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "absolute URI or 'none'"
+    },
+    "cue": {
+      "name": "cue",
+      "value": "[ <'cue-before'> || <'cue-after'> ] | inherit",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "see individual properties"
+    },
+    "play-during": {
+      "name": "play-during",
+      "value": "<uri> [ mix || repeat ]? | auto | none | inherit",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "absolute URI, rest as specified"
+    },
+    "azimuth": {
+      "name": "azimuth",
+      "value": "<angle> | [[ left-side | far-left | left | center-left | center | center-right | right | far-right | right-side ] || behind ] | leftwards | rightwards | inherit",
+      "initial": "center",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "normalized angle"
+    },
+    "elevation": {
+      "name": "elevation",
+      "value": "<angle> | below | level | above | higher | lower | inherit",
+      "initial": "level",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "normalized angle"
+    },
+    "speech-rate": {
+      "name": "speech-rate",
+      "value": "<number> | x-slow | slow | medium | fast | x-fast | faster | slower | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "number"
+    },
+    "voice-family": {
+      "name": "voice-family",
+      "value": "[[<specific-voice> | <generic-voice> ],]* [<specific-voice> | <generic-voice> ] | inherit",
+      "initial": "depends on user agent",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    },
+    "pitch": {
+      "name": "pitch",
+      "value": "<frequency> | x-low | low | medium | high | x-high | inherit",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "frequency"
+    },
+    "pitch-range": {
+      "name": "pitch-range",
+      "value": "<number> | inherit",
+      "initial": "50",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    },
+    "stress": {
+      "name": "stress",
+      "value": "<number> | inherit",
+      "initial": "50",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    },
+    "richness": {
+      "name": "richness",
+      "value": "<number> | inherit",
+      "initial": "50",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    },
+    "speak-punctuation": {
+      "name": "speak-punctuation",
+      "value": "code | none | inherit",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    },
+    "speak-numeral": {
+      "name": "speak-numeral",
+      "value": "digits | continuous | inherit",
+      "initial": "continuous",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    },
+    "speak-header": {
+      "name": "speak-header",
+      "value": "once | always | inherit",
+      "initial": "once",
+      "appliesTo": "elements that have table header information",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "aural",
+      "computed value": "as specified"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/SVG.json b/whatwg/css/SVG.json
new file mode 100644
index 000000000000..2171481ca404
--- /dev/null
+++ b/whatwg/css/SVG.json
@@ -0,0 +1,434 @@
+{
+  "properties": {
+    "cx": {
+      "name": "cx",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "‘circle’ and ‘ellipse’",
+      "inherited": "no",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computedValue": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "cy": {
+      "name": "cy",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "‘circle’ and ‘ellipse’",
+      "inherited": "no",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computedValue": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "r": {
+      "name": "r",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "‘circle’",
+      "inherited": "no",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computedValue": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "rx": {
+      "name": "rx",
+      "value": "<length-percentage> | auto",
+      "initial": "auto",
+      "appliesTo": "‘ellipse’, ‘rect’",
+      "inherited": "no",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computedValue": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "ry": {
+      "name": "ry",
+      "value": "<length-percentage> | auto",
+      "initial": "auto",
+      "appliesTo": "‘ellipse’, ‘rect’",
+      "inherited": "no",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computedValue": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "x": {
+      "name": "x",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "‘svg’, ‘rect’, ‘image’, ‘foreignObject’",
+      "inherited": "no",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computedValue": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "y": {
+      "name": "y",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "‘svg’, ‘rect’, ‘image’, ‘foreignObject’",
+      "inherited": "no",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computedValue": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "vector-effect": {
+      "name": "vector-effect",
+      "value": "none | [ non-scaling-stroke | non-scaling-size | non-rotation | fixed-position ]+ [ viewport | screen ]?",
+      "initial": "none",
+      "appliesTo": "graphics elements and ‘use’",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "d": {
+      "name": "d",
+      "value": "none | <string>",
+      "initial": "none",
+      "appliesTo": "‘path’",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "inline-size": {
+      "name": "inline-size",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "‘text’ elements",
+      "inherited": "no",
+      "percentages": "Refer to the width (for horizontal text) or height (for vertical text) of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "shape-inside": {
+      "name": "shape-inside",
+      "value": "auto | [ <basic-shape> | <uri> ]+",
+      "initial": "auto",
+      "appliesTo": "‘text’ elements",
+      "inherited": "no",
+      "percentages": "Relative to the ‘viewBox’",
+      "media": "visual",
+      "computed value": "computed lengths for <shape>, the absolute URI for <uri>, otherwise as specified",
+      "animatable": "yes, see Interpolation of Basic Shapes"
+    },
+    "shape-subtract": {
+      "name": "shape-subtract",
+      "value": "none | [ <basic-shape>| <uri> ]+",
+      "initial": "none",
+      "appliesTo": "‘text’ elements",
+      "inherited": "no",
+      "percentages": "Relative to the ‘viewBox’",
+      "media": "visual",
+      "computed value": "computed lengths for any <basic-shape>, the absolute URI for <uri>, otherwise as specified",
+      "animatable": "yes, see Interpolation of Basic Shapes"
+    },
+    "shape-margin": {
+      "name": "shape-margin",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "‘text’ elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "the absolute length",
+      "animatable": "yes"
+    },
+    "text-anchor": {
+      "name": "text-anchor",
+      "value": "start | middle | end",
+      "initial": "start",
+      "appliesTo": "text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "text-decoration-fill": {
+      "name": "text-decoration-fill",
+      "value": "<paint>",
+      "initial": "See prose.",
+      "appliesTo": "text content elements",
+      "inherited": "See prose.",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <color> values computed and <url> values made absolute.",
+      "animatable": "yes"
+    },
+    "text-decoration-stroke": {
+      "name": "text-decoration-stroke",
+      "value": "<paint>",
+      "initial": "See prose.",
+      "appliesTo": "text content elements",
+      "inherited": "See prose.",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <color> values computed and <url> values made absolute.",
+      "animatable": "yes"
+    },
+    "fill": {
+      "name": "fill",
+      "value": "<paint>",
+      "initial": "black",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <color> values computed and <url> values made absolute",
+      "animatable": "yes"
+    },
+    "fill-rule": {
+      "name": "fill-rule",
+      "value": "nonzero | evenodd",
+      "initial": "nonzero",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "fill-opacity": {
+      "name": "fill-opacity",
+      "value": "<alpha-value>",
+      "initial": "1",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "the specified value converted to a number, clamped to the range [0,1]",
+      "animatable": "yes"
+    },
+    "stroke": {
+      "name": "stroke",
+      "value": "<paint>",
+      "initial": "none",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <color> values computed and <url> values made absolute",
+      "animatable": "yes"
+    },
+    "stroke-opacity": {
+      "name": "stroke-opacity",
+      "value": "<alpha-value>",
+      "initial": "1",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "the specified value converted to a number, clamped to the range [0,1]",
+      "animatable": "yes"
+    },
+    "stroke-width": {
+      "name": "stroke-width",
+      "value": "<length-percentage>",
+      "initial": "1",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "stroke-linecap": {
+      "name": "stroke-linecap",
+      "value": "butt | round | square",
+      "initial": "butt",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "stroke-linejoin": {
+      "name": "stroke-linejoin",
+      "value": "miter | miter-clip | round | bevel | arcs",
+      "initial": "miter",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "stroke-miterlimit": {
+      "name": "stroke-miterlimit",
+      "value": "<number>",
+      "initial": "4",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "stroke-dasharray": {
+      "name": "stroke-dasharray",
+      "value": "none | <dasharray>",
+      "initial": "none",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute lengths or percentages for <dasharray>, or keyword specified",
+      "animatable": "yes (non-additive)"
+    },
+    "stroke-dashoffset": {
+      "name": "stroke-dashoffset",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "refer to the size of the current SVG viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "marker-start": {
+      "name": "marker-start",
+      "value": "none | <marker-ref>",
+      "initial": "none",
+      "appliesTo": "shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker-mid": {
+      "name": "marker-mid",
+      "value": "none | <marker-ref>",
+      "initial": "none",
+      "appliesTo": "shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker-end": {
+      "name": "marker-end",
+      "value": "none | <marker-ref>",
+      "initial": "none",
+      "appliesTo": "shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker": {
+      "name": "marker",
+      "value": "none | <marker-ref>",
+      "initial": "not defined for shorthand properties",
+      "appliesTo": "shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties",
+      "animatable": "yes"
+    },
+    "paint-order": {
+      "name": "paint-order",
+      "value": "normal | [ fill || stroke || markers ]",
+      "initial": "normal",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "color-interpolation": {
+      "name": "color-interpolation",
+      "value": "auto | sRGB | linearRGB",
+      "initial": "sRGB",
+      "appliesTo": "container elements, graphics elements, gradient elements, ‘use’ and ‘animate’",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "color-rendering": {
+      "name": "color-rendering",
+      "value": "auto | optimizeSpeed | optimizeQuality",
+      "initial": "auto",
+      "appliesTo": "container elements, graphics elements, gradient elements, ‘use’ and ‘animate’",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "shape-rendering": {
+      "name": "shape-rendering",
+      "value": "auto | optimizeSpeed | crispEdges | geometricPrecision",
+      "initial": "auto",
+      "appliesTo": "shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "text-rendering": {
+      "name": "text-rendering",
+      "value": "auto | optimizeSpeed | optimizeLegibility | geometricPrecision",
+      "initial": "auto",
+      "appliesTo": "‘text’",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "image-rendering": {
+      "name": "image-rendering",
+      "value": "auto | optimizeQuality | optimizeSpeed",
+      "initial": "auto",
+      "appliesTo": "images",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "pointer-events": {
+      "name": "pointer-events",
+      "value": "bounding-box | visiblePainted | visibleFill | visibleStroke | visible | painted | fill | stroke | all | none",
+      "initial": "visiblePainted",
+      "appliesTo": "container elements, graphics elements and ‘use’",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<points>": {
+      "value": "[ <number>+ ]#"
+    },
+    "<dasharray>": {
+      "value": "[ <length-percentage> | <number> ]#*"
+    },
+    "<marker-ref>": {
+      "value": "<url>"
+    }
+  }
+}
diff --git a/whatwg/css/compat.json b/whatwg/css/compat.json
new file mode 100644
index 000000000000..3b26b09d34d6
--- /dev/null
+++ b/whatwg/css/compat.json
@@ -0,0 +1,91 @@
+{
+  "properties": {
+    "-webkit-background-clip": {
+      "name": "-webkit-background-clip",
+      "value": "border-box | padding-box | content-box | text",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "\"text\"",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "-webkit-text-fill-color": {
+      "name": "-webkit-text-fill-color",
+      "value": "<color>",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "an RGBA color",
+      "canonicalOrder": "per grammar",
+      "animationType": "as color"
+    },
+    "-webkit-text-stroke-color": {
+      "name": "-webkit-text-stroke-color",
+      "value": "<color>",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "an RGBA color",
+      "canonicalOrder": "per grammar",
+      "animationType": "as color"
+    },
+    "-webkit-text-stroke-width": {
+      "name": "-webkit-text-stroke-width",
+      "value": "<line-width>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "-webkit-text-stroke": {
+      "name": "-webkit-text-stroke",
+      "value": "<line-width> || <color>",
+      "initial": "See individual properties",
+      "appliesTo": "See individual properties",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "See individual properties",
+      "canonicalOrder": "per grammar",
+      "animationType": "See individual properties"
+    },
+    "touch-action": {
+      "name": "touch-action",
+      "value": "auto | none | [ [ pan-x | pan-left | pan-right ] || [ pan-y | pan-up | pan-down ] || pinch-zoom ] | manipulation",
+      "initial": "auto",
+      "appliesTo": "all elements except: non-replaced inline elements, table rows, row groups, table columns, and column groups.",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "Same as specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {
+    "-webkit-device-pixel-ratio": {
+      "name": "-webkit-device-pixel-ratio",
+      "for": "@media",
+      "value": "<number>",
+      "type": "range"
+    },
+    "-webkit-transform-3d": {
+      "name": "-webkit-transform-3d",
+      "for": "@media",
+      "value": "<mq-boolean>",
+      "acceptsMin/maxPrefixes": "no"
+    }
+  },
+  "valuespaces": {}
+}
diff --git a/whatwg/css/compositing.json b/whatwg/css/compositing.json
new file mode 100644
index 000000000000..ba22133d8dc1
--- /dev/null
+++ b/whatwg/css/compositing.json
@@ -0,0 +1,52 @@
+{
+  "properties": {
+    "mix-blend-mode": {
+      "name": "mix-blend-mode",
+      "value": "<blend-mode>",
+      "initial": "normal",
+      "appliesTo": "All elements. In SVG, it applies to container elements, graphics elements and graphics referencing elements. [SVG11]",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "isolation": {
+      "name": "isolation",
+      "value": "<isolation-mode>",
+      "initial": "auto",
+      "appliesTo": "All elements. In SVG, it applies to container elements, graphics elements and graphics referencing elements. [SVG11]",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "background-blend-mode": {
+      "name": "background-blend-mode",
+      "value": "<blend-mode>#",
+      "initial": "normal",
+      "appliesTo": "All HTML elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<blend-mode>": {
+      "value": "normal | multiply | screen | overlay | darken | lighten | color-dodge |color-burn | hard-light | soft-light | difference | exclusion | hue | saturation | color | luminosity"
+    },
+    "<isolation-mode>": {
+      "value": "auto | isolate"
+    },
+    "<composite-mode>": {
+      "value": "clear | copy | source-over | destination-over | source-in | destination-in | source-out | destination-out | source-atop | destination-atop | xor | lighter | plus-darker | plus-lighter"
+    }
+  }
+}
diff --git a/whatwg/css/css-align.json b/whatwg/css/css-align.json
new file mode 100644
index 000000000000..1f615ddf3dff
--- /dev/null
+++ b/whatwg/css/css-align.json
@@ -0,0 +1,154 @@
+{
+  "properties": {
+    "align-content": {
+      "name": "align-content",
+      "value": "normal | <baseline-position> | <content-distribution> | <overflow-position>? <content-position>",
+      "initial": "normal",
+      "appliesTo": "block containers, multicol containers, flex containers, and grid containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "justify-content": {
+      "name": "justify-content",
+      "value": "normal | <content-distribution> | <overflow-position>? [ <content-position> | left | right ]",
+      "initial": "normal",
+      "appliesTo": "multicol containers, flex containers, and grid containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "place-content": {
+      "name": "place-content",
+      "value": "<‘align-content’> <‘justify-content’>?",
+      "initial": "normal",
+      "appliesTo": "block containers, flex containers, and grid containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "justify-self": {
+      "name": "justify-self",
+      "value": "auto | normal | stretch | <baseline-position> | <overflow-position>? [ <self-position> | left | right ]",
+      "initial": "auto",
+      "appliesTo": "block-level boxes, absolutely-positioned boxes, and grid items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "align-self": {
+      "name": "align-self",
+      "value": "auto | normal | stretch | <baseline-position> | <overflow-position>? <self-position>",
+      "initial": "auto",
+      "appliesTo": "flex items, grid items, and absolutely-positioned boxes",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "place-self": {
+      "name": "place-self",
+      "value": "<‘align-self’> <‘justify-self’>?",
+      "initial": "auto",
+      "appliesTo": "block-level boxes, absolutely-positioned boxes, and grid items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "justify-items": {
+      "name": "justify-items",
+      "value": "normal | stretch | <baseline-position> | <overflow-position>? [ <self-position> | left | right ] | legacy | legacy && [ left | right | center ]",
+      "initial": "legacy",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value, except for legacy (see prose)",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "align-items": {
+      "name": "align-items",
+      "value": "normal | stretch | <baseline-position> | [ <overflow-position>? <self-position> ]",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "place-items": {
+      "name": "place-items",
+      "value": "<‘align-items’> <‘justify-items’>?",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "row-gap": {
+      "name": "row-gap",
+      "value": "normal | <length-percentage>",
+      "initial": "normal",
+      "appliesTo": "multi-column containers, flex containers, grid containers",
+      "inherited": "no",
+      "percentages": "refer to corresponding dimension of the content area",
+      "computedValue": "as specified, with <length>s made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "column-gap": {
+      "name": "column-gap",
+      "value": "normal | <length-percentage>",
+      "initial": "normal",
+      "appliesTo": "multi-column containers, flex containers, grid containers",
+      "inherited": "no",
+      "percentages": "refer to corresponding dimension of the content area",
+      "computedValue": "as specified, with <length>s made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "gap": {
+      "name": "gap",
+      "value": "<‘row-gap’> <‘column-gap’>?",
+      "initial": "see individual properties",
+      "appliesTo": "multi-column containers, flex containers, grid containers",
+      "inherited": "no",
+      "percentages": "refer to corresponding dimension of the content area",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<self-position>": {
+      "value": "center | start | end | self-start | self-end | flex-start | flex-end;"
+    },
+    "<content-position>": {
+      "value": "center | start | end | flex-start | flex-end;"
+    },
+    "<baseline-position>": {
+      "value": "[ first | last ]? baseline"
+    },
+    "<content-distribution>": {
+      "value": "space-between | space-around | space-evenly | stretch"
+    },
+    "<overflow-position>": {
+      "value": "unsafe | safe"
+    }
+  }
+}
diff --git a/whatwg/css/css-animations.json b/whatwg/css/css-animations.json
new file mode 100644
index 000000000000..4835c287d25f
--- /dev/null
+++ b/whatwg/css/css-animations.json
@@ -0,0 +1,21 @@
+{
+  "properties": {
+    "animation-composition": {
+      "name": "animation-composition",
+      "value": "<single-animation-composition>#",
+      "initial": "replace",
+      "appliesTo": "all elements, ::before and ::after pseudo-elements",
+      "inherited": "none",
+      "percentages": "N/A",
+      "computedValue": "As specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<single-animation-composition>": {
+      "value": "replace | add | accumulate"
+    }
+  }
+}
diff --git a/whatwg/css/css-backgrounds.json b/whatwg/css/css-backgrounds.json
new file mode 100644
index 000000000000..dfc18a193173
--- /dev/null
+++ b/whatwg/css/css-backgrounds.json
@@ -0,0 +1,233 @@
+{
+  "properties": {
+    "background-position": {
+      "name": "background-position",
+      "value": "<position>#",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "background-position-x": {
+      "name": "background-position-x",
+      "value": "[ center | [ left | right | x-start | x-end ]? <length-percentage>? ]#",
+      "initial": "left",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to width of background positioning area minus width of background image",
+      "computedValue": "A list, each item consisting of: an offset given as a combination of an absolute length and a percentage, plus an origin keyword",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "background-position-y": {
+      "name": "background-position-y",
+      "value": "[ center | [ top | bottom | y-start | y-end ]? <length-percentage>? ]#",
+      "initial": "left",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to height of background positioning area minus height of background image",
+      "computedValue": "A list, each item consisting of: an offset given as a combination of an absolute length and a percentage, plus an origin keyword",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "background-position-inline": {
+      "name": "background-position-inline",
+      "value": "[ center | [ start | end ]? <length-percentage>? ]#",
+      "initial": "not applicable (initial value comes from physical property)",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to inline-size of background positioning area minus inline-size of background image",
+      "computedValue": "A list, each item consisting of: an offset given as a combination of an absolute length and a percentage, plus an origin keyword",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "background-position-block": {
+      "name": "background-position-block",
+      "value": "[ center | [ start | end ]? <length-percentage>? ]#",
+      "initial": "not applicable (initial value comes from physical property)",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to size of background positioning area minus size of background image",
+      "computedValue": "A list, each item consisting of: an offset given as a combination of an absolute length and a percentage, plus an origin keyword",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "background-clip": {
+      "name": "background-clip",
+      "value": "<bg-clip>#",
+      "initial": "border-box",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-top-color": {
+      "name": "border-top-color",
+      "value": "<color>#",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "the computed color",
+      "canonicalOrder": "per grammar",
+      "animationType": "see prose"
+    },
+    "border-right-color": {
+      "name": "border-right-color",
+      "value": "<color>#",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "the computed color",
+      "canonicalOrder": "per grammar",
+      "animationType": "see prose"
+    },
+    "border-bottom-color": {
+      "name": "border-bottom-color",
+      "value": "<color>#",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "the computed color",
+      "canonicalOrder": "per grammar",
+      "animationType": "see prose"
+    },
+    "border-left-color": {
+      "name": "border-left-color",
+      "value": "<color>#",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "the computed color",
+      "canonicalOrder": "per grammar",
+      "animationType": "see prose"
+    },
+    "border-color": {
+      "name": "border-color",
+      "value": "<color>{1,4}#",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-radius": {
+      "name": "border-radius",
+      "value": "<length-percentage>{1,4} [ / <length-percentage>{1,4} ]?",
+      "initial": "0",
+      "appliesTo": "all elements, except table element when border-collapse is collapse",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "corner-shape": {
+      "name": "corner-shape",
+      "value": "[ round | bevel | scoop | notch ]{1,4}",
+      "initial": "round",
+      "appliesTo": "all elements, except table element when border-collapse is collapse",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "corners": {
+      "name": "corners",
+      "value": "<‘corner-shape’> || <‘border-radius’>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-limit": {
+      "name": "border-limit",
+      "value": "all | [ sides | corners ] <length-percentage>? | [ top | right | bottom | left ] <length-percentage>",
+      "initial": "round",
+      "appliesTo": "all elements, except table element when border-collapse is collapse",
+      "inherited": "no",
+      "percentages": "relative to border-box",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-clip": {
+      "name": "border-clip",
+      "value": "normal | [ <length-percentage> | <flex> ]+",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to length of border-edge side",
+      "computedValue": "normal, or a list consisting of absolute lengths, or percentages as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-clip-top": {
+      "name": "border-clip-top",
+      "value": "normal | [ <length-percentage> | <flex> ]+",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to length of border-edge side",
+      "computedValue": "normal, or a list consisting of absolute lengths, or percentages as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-clip-right": {
+      "name": "border-clip-right",
+      "value": "normal | [ <length-percentage> | <flex> ]+",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to length of border-edge side",
+      "computedValue": "normal, or a list consisting of absolute lengths, or percentages as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-clip-bottom": {
+      "name": "border-clip-bottom",
+      "value": "normal | [ <length-percentage> | <flex> ]+",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to length of border-edge side",
+      "computedValue": "normal, or a list consisting of absolute lengths, or percentages as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-clip-left": {
+      "name": "border-clip-left",
+      "value": "normal | [ <length-percentage> | <flex> ]+",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "refer to length of border-edge side",
+      "computedValue": "normal, or a list consisting of absolute lengths, or percentages as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<position>": {
+      "value": "[ [ left | center | right | top | bottom | start | end | <length-percentage> ] | [ left | center | right | x-start | x-end | <length-percentage> ] [ top | center | bottom | y-start | y-end | <length-percentage> ] | [ center | [ left | right | x-start | x-end ] <length-percentage>? ] && [ center | [ top | bottom | y-start | y-end ] <length-percentage>? ] | [ center | [ start | end ] <length-percentage>? ] [ center | [ start | end ] <length-percentage>? ] ]"
+    },
+    "<bg-clip>": {
+      "value": "<box> | border | text"
+    }
+  }
+}
diff --git a/whatwg/css/css-box.json b/whatwg/css/css-box.json
new file mode 100644
index 000000000000..032c3e09cb4d
--- /dev/null
+++ b/whatwg/css/css-box.json
@@ -0,0 +1,116 @@
+{
+  "properties": {
+    "margin-top": {
+      "name": "margin-top",
+      "value": "<length-percentage> | auto",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "margin-right": {
+      "name": "margin-right",
+      "value": "<length-percentage> | auto",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "margin-bottom": {
+      "name": "margin-bottom",
+      "value": "<length-percentage> | auto",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "margin-left": {
+      "name": "margin-left",
+      "value": "<length-percentage> | auto",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "margin": {
+      "name": "margin",
+      "value": "<‘margin-top’>{1,4}",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "padding-top": {
+      "name": "padding-top",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "padding-right": {
+      "name": "padding-right",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "padding-bottom": {
+      "name": "padding-bottom",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "padding-left": {
+      "name": "padding-left",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "padding": {
+      "name": "padding",
+      "value": "<‘padding-top’>{1,4}",
+      "initial": "0",
+      "appliesTo": "all elements except internal table elements",
+      "inherited": "no",
+      "percentages": "refer to logical width of containing block",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-break.json b/whatwg/css/css-break.json
new file mode 100644
index 000000000000..620694d28043
--- /dev/null
+++ b/whatwg/css/css-break.json
@@ -0,0 +1,72 @@
+{
+  "properties": {
+    "break-before": {
+      "name": "break-before",
+      "value": "auto | avoid | avoid-page | page | left | right | recto | verso | avoid-column | column | avoid-region | region",
+      "initial": "auto",
+      "appliesTo": "block-level elements, table row groups, table rows (but see prose)",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "break-after": {
+      "name": "break-after",
+      "value": "auto | avoid | avoid-page | page | left | right | recto | verso | avoid-column | column | avoid-region | region",
+      "initial": "auto",
+      "appliesTo": "block-level elements, table row groups, table rows (but see prose)",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "break-inside": {
+      "name": "break-inside",
+      "value": "auto | avoid | avoid-page | avoid-column | avoid-region",
+      "initial": "auto",
+      "appliesTo": "elements in the normal flow that establish formatting contexts, or that are block containers, table row groups, or table rows",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "orphans": {
+      "name": "orphans",
+      "value": "<integer>",
+      "initial": "2",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "widows": {
+      "name": "widows",
+      "value": "<integer>",
+      "initial": "2",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "box-decoration-break": {
+      "name": "box-decoration-break",
+      "value": "slice | clone",
+      "initial": "slice",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-cascade.json b/whatwg/css/css-cascade.json
new file mode 100644
index 000000000000..fec8cb9a4670
--- /dev/null
+++ b/whatwg/css/css-cascade.json
@@ -0,0 +1,16 @@
+{
+  "properties": {
+    "all": {
+      "name": "all",
+      "value": "initial | inherit | unset | revert",
+      "initial": "See individual properties",
+      "appliesTo": "See individual properties",
+      "inherited": "See individual properties",
+      "percentages": "See individual properties",
+      "computedValue": "See individual properties",
+      "animatable": "See individual properties"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-color.json b/whatwg/css/css-color.json
new file mode 100644
index 000000000000..8f7cf27bad92
--- /dev/null
+++ b/whatwg/css/css-color.json
@@ -0,0 +1,89 @@
+{
+  "properties": {
+    "color": {
+      "name": "color",
+      "value": "<color>",
+      "initial": "UA-defined, see prose",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "See resolving color values",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "opacity": {
+      "name": "opacity",
+      "value": "<alpha-value>",
+      "initial": "1",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "the specified value converted to a number, clamped to the range [0,1]",
+      "canonicalOrder": "per grammar",
+      "animationType": "as number"
+    },
+    "color-adjust": {
+      "name": "color-adjust",
+      "value": "economy | exact",
+      "initial": "economy",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {
+    "src": {
+      "name": "src",
+      "for": "@color-profile",
+      "value": "<url>",
+      "initial": "n/a"
+    },
+    "rendering-intent": {
+      "name": "rendering-intent",
+      "for": "@color-profile",
+      "value": "relative-colorimetric | absolute-colorimetric | perceptual | saturation",
+      "initial": "relative-colorimetric"
+    }
+  },
+  "valuespaces": {
+    "<color>": {
+      "value": "<rgb()> | <rgba()> | <hsl()> | <hsla()> | <hwb()> | <gray()> | <device-cmyk()> | <hex-color> | <named-color> | currentcolor | <deprecated-system-color>"
+    },
+    "<rgb()>": {
+      "value": "rgb( <percentage>{3} [ / <alpha-value> ]? ) | rgb( <number>{3} [ / <alpha-value> ]? )"
+    },
+    "<alpha-value>": {
+      "value": "<number> | <percentage>"
+    },
+    "<hsl()>": {
+      "value": "hsl( <hue> <percentage> <percentage> [ / <alpha-value> ]? )"
+    },
+    "<hue>": {
+      "value": "<number> | <angle>"
+    },
+    "<hwb()>": {
+      "value": "hwb( <hue> <percentage> <percentage> [ / <alpha-value> ]? )"
+    },
+    "<lab()>": {
+      "value": "lab( <number> <number> <number> [ / <alpha-value> ]? )"
+    },
+    "<lch()>": {
+      "value": "lch( <number> <number> <hue> [ / <alpha-value> ]? )"
+    },
+    "<gray()>": {
+      "value": "gray( <number> [ / <alpha-value> ]? )"
+    },
+    "<color()>": {
+      "value": "color( [ <ident>? [ <number>+ | <string> ] [ / <alpha-value> ]? ]# , <color>? )"
+    },
+    "<device-cmyk()>": {
+      "value": "device-cmyk( <cmyk-component>{4} [ / <alpha-value> ]? , <color>? )"
+    },
+    "<cmyk-component>": {
+      "value": "<number> | <percentage>"
+    }
+  }
+}
diff --git a/whatwg/css/css-conditional.json b/whatwg/css/css-conditional.json
new file mode 100644
index 000000000000..f47bdfe0b5f7
--- /dev/null
+++ b/whatwg/css/css-conditional.json
@@ -0,0 +1,18 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<supports-condition>": {
+      "value": "not <supports-in-parens> | <supports-in-parens> [ and <supports-in-parens> ]* | <supports-in-parens> [ or <supports-in-parens> ]*"
+    },
+    "<supports-in-parens>": {
+      "value": "( <supports-condition> ) | <supports-feature> | <general-enclosed>"
+    },
+    "<supports-feature>": {
+      "value": "<supports-decl>"
+    },
+    "<supports-decl>": {
+      "value": "( <declaration> )"
+    }
+  }
+}
diff --git a/whatwg/css/css-contain.json b/whatwg/css/css-contain.json
new file mode 100644
index 000000000000..b9273eb72232
--- /dev/null
+++ b/whatwg/css/css-contain.json
@@ -0,0 +1,17 @@
+{
+  "properties": {
+    "contain": {
+      "name": "contain",
+      "value": "none | strict | content | [ size || layout || style || paint ]",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "not animatable"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-content.json b/whatwg/css/css-content.json
new file mode 100644
index 000000000000..2acc1e10a90f
--- /dev/null
+++ b/whatwg/css/css-content.json
@@ -0,0 +1,106 @@
+{
+  "properties": {
+    "content": {
+      "name": "content",
+      "value": "normal | none | [ <content-replacement> | <content-list> ] [/ <string> ]?",
+      "initial": "normal",
+      "appliesTo": "all elements, tree-abiding pseudo-elements, and page margin boxes",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "As specified below",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "quotes": {
+      "name": "quotes",
+      "value": "none | [ <string> <string> ]+",
+      "initial": "depends on user agent",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "string-set": {
+      "name": "string-set",
+      "value": "none | [ <custom-ident> <string>+ ]#",
+      "initial": "none",
+      "appliesTo": "all elements, but not pseudo-elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "bookmark-level": {
+      "name": "bookmark-level",
+      "value": "none | <integer>",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "bookmark-label": {
+      "name": "bookmark-label",
+      "value": "<content-list>",
+      "initial": "content(text)",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "bookmark-state": {
+      "name": "bookmark-state",
+      "value": "open | closed",
+      "initial": "open",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<quote>": {
+      "value": "open-quote | close-quote | no-open-quote | no-close-quote"
+    },
+    "<leader()>": {
+      "value": "leader( <leader-type> )"
+    },
+    "<leader-type>": {
+      "value": "dotted | solid | space | <string>"
+    },
+    "<target>": {
+      "value": "<target-counter()> | <target-counters()> | <target-text()>"
+    },
+    "<target-counter()>": {
+      "value": "target-counter( [ <string> | <url> ] , <custom-ident> , <counter-style>? )"
+    },
+    "<target-counters()>": {
+      "value": "target-counters( [ <string> | <url> ] , <custom-ident> , <string> , <counter-style>? )"
+    },
+    "<target-text()>": {
+      "value": "target-text( [ <string> | <url> ] , [ content | before | after | first-letter ]? )"
+    },
+    "<string()>": {
+      "value": "string( <custom-ident> , [ first | start | last | first-except ]? )"
+    },
+    "<content()>": {
+      "value": "content( [ text | before | after | first-letter | marker ]? )"
+    },
+    "<content-replacement>": {
+      "value": "<image>"
+    },
+    "<content-list>": {
+      "value": "[ <string> | contents | <image> | <quote> | <target> | <leader()> ]+"
+    }
+  }
+}
diff --git a/whatwg/css/css-counter-styles.json b/whatwg/css/css-counter-styles.json
new file mode 100644
index 000000000000..0f7dfeef2c13
--- /dev/null
+++ b/whatwg/css/css-counter-styles.json
@@ -0,0 +1,79 @@
+{
+  "properties": {},
+  "descriptors": {
+    "system": {
+      "name": "system",
+      "for": "@counter-style",
+      "value": "cyclic | numeric | alphabetic | symbolic | additive | [fixed <integer>?] | [ extends <counter-style-name> ]",
+      "initial": "symbolic"
+    },
+    "negative": {
+      "name": "negative",
+      "for": "@counter-style",
+      "value": "<symbol> <symbol>?",
+      "initial": "\"\\2D\" (\"-\" hyphen-minus)"
+    },
+    "prefix": {
+      "name": "prefix",
+      "for": "@counter-style",
+      "value": "<symbol>",
+      "initial": "\"\" (the empty string)"
+    },
+    "suffix": {
+      "name": "suffix",
+      "for": "@counter-style",
+      "value": "<symbol>",
+      "initial": "\"\\2E\\20\" (\".\" full stop followed by a space)"
+    },
+    "range": {
+      "name": "range",
+      "for": "@counter-style",
+      "value": "[ [ <integer> | infinite ]{2} ]# | auto",
+      "initial": "auto"
+    },
+    "pad": {
+      "name": "pad",
+      "for": "@counter-style",
+      "value": "<integer> && <symbol>",
+      "initial": "0 \"\""
+    },
+    "fallback": {
+      "name": "fallback",
+      "for": "@counter-style",
+      "value": "<counter-style-name>",
+      "initial": "decimal"
+    },
+    "symbols": {
+      "name": "symbols",
+      "for": "@counter-style",
+      "value": "<symbol>+",
+      "initial": "n/a"
+    },
+    "additive-symbols": {
+      "name": "additive-symbols",
+      "for": "@counter-style",
+      "value": "[ <integer> && <symbol> ]#",
+      "initial": "n/a"
+    },
+    "speak-as": {
+      "name": "speak-as",
+      "for": "@counter-style",
+      "value": "auto | bullets | numbers | words | spell-out | <counter-style-name>",
+      "initial": "auto"
+    }
+  },
+  "valuespaces": {
+    "<symbol>": {
+      "value": "<string> | <image> | <custom-ident>"
+    },
+    "<symbols()>": {
+      "value": "symbols( <symbols-type>? [ <string> | <image> ]+ );"
+    },
+    "<symbols-type>": {
+      "value": "cyclic | numeric | alphabetic | symbolic | fixed;"
+    },
+    "<counter-style>": {
+      "value": "<counter-style-name> | symbols();"
+    }
+  }
+}
diff --git a/whatwg/css/css-device-adapt.json b/whatwg/css/css-device-adapt.json
new file mode 100644
index 000000000000..92a904925734
--- /dev/null
+++ b/whatwg/css/css-device-adapt.json
@@ -0,0 +1,98 @@
+{
+  "properties": {},
+  "descriptors": {
+    "min-width": {
+      "name": "min-width",
+      "for": "@viewport",
+      "value": "<viewport-length>",
+      "initial": "auto",
+      "percentages": "Refer to the width of the initial viewport",
+      "computedValue": "auto, an absolute length, or a percentage as specified"
+    },
+    "max-width": {
+      "name": "max-width",
+      "for": "@viewport",
+      "value": "<viewport-length>",
+      "initial": "auto",
+      "percentages": "Refer to the width of the initial viewport",
+      "computedValue": "auto, an absolute length, or a percentage as specified"
+    },
+    "width": {
+      "name": "width",
+      "for": "@viewport",
+      "value": "<viewport-length>{1,2}",
+      "initial": "See individual descriptors",
+      "percentages": "See individual descriptors",
+      "computedValue": "See individual descriptors"
+    },
+    "min-height": {
+      "name": "min-height",
+      "for": "@viewport",
+      "value": "<viewport-length>",
+      "initial": "auto",
+      "percentages": "Refer to the height of the initial viewport",
+      "computedValue": "auto, an absolute length, or a percentage as specified"
+    },
+    "max-height": {
+      "name": "max-height",
+      "for": "@viewport",
+      "value": "<viewport-length>",
+      "initial": "auto",
+      "percentages": "Refer to the height of the initial viewport",
+      "computedValue": "auto, an absolute length, or a percentage as specified"
+    },
+    "height": {
+      "name": "height",
+      "for": "@viewport",
+      "value": "<viewport-length>{1,2}",
+      "initial": "See individual descriptors",
+      "percentages": "See individual descriptors",
+      "computedValue": "See individual descriptors"
+    },
+    "zoom": {
+      "name": "zoom",
+      "for": "@viewport",
+      "value": "auto | <number> | <percentage>",
+      "initial": "auto",
+      "percentages": "The zoom factor itself",
+      "computedValue": "auto, or a non-negative number or percentage as specified"
+    },
+    "min-zoom": {
+      "name": "min-zoom",
+      "for": "@viewport",
+      "value": "auto | <number> | <percentage>",
+      "initial": "auto",
+      "percentages": "The zoom factor itself",
+      "computedValue": "auto, or a non-negative number or percentage as specified"
+    },
+    "max-zoom": {
+      "name": "max-zoom",
+      "for": "@viewport",
+      "value": "auto | <number> | <percentage>",
+      "initial": "auto",
+      "percentages": "The zoom factor itself",
+      "computedValue": "auto, or a non-negative number or percentage as specified"
+    },
+    "user-zoom": {
+      "name": "user-zoom",
+      "for": "@viewport",
+      "value": "zoom | fixed",
+      "initial": "zoom",
+      "percentages": "N/A",
+      "computedValue": "as specified"
+    },
+    "orientation": {
+      "name": "orientation",
+      "for": "@viewport",
+      "value": "auto | portrait | landscape",
+      "initial": "auto",
+      "percentages": "N/A",
+      "computedValue": "as specified"
+    }
+  },
+  "valuespaces": {
+    "<viewport-length>": {
+      "value": "auto | <length> | <percentage>"
+    }
+  }
+}
diff --git a/whatwg/css/css-display.json b/whatwg/css/css-display.json
new file mode 100644
index 000000000000..c5124130cadf
--- /dev/null
+++ b/whatwg/css/css-display.json
@@ -0,0 +1,36 @@
+{
+  "properties": {
+    "display": {
+      "name": "display",
+      "value": "[ <display-outside> || <display-inside> ] | <display-listitem> | <display-internal> | <display-box> | <display-legacy>",
+      "initial": "inline",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "see prose in a variety of specs",
+      "canonicalOrder": "per grammar",
+      "animationType": "not animatable"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<display-outside>": {
+      "value": "block | inline | run-in ;"
+    },
+    "<display-inside>": {
+      "value": "flow | flow-root | table | flex | grid | ruby ;"
+    },
+    "<display-listitem>": {
+      "value": "<display-outside>? && [ flow | flow-root ]? && list-item ;"
+    },
+    "<display-internal>": {
+      "value": "table-row-group | table-header-group | table-footer-group | table-row | table-cell | table-column-group | table-column | table-caption | ruby-base | ruby-text | ruby-base-container | ruby-text-container ;"
+    },
+    "<display-box>": {
+      "value": "contents | none ;"
+    },
+    "<display-legacy>": {
+      "value": "inline-block | inline-table | inline-flex | inline-grid ;"
+    }
+  }
+}
diff --git a/whatwg/css/css-env.json b/whatwg/css/css-env.json
new file mode 100644
index 000000000000..23118de93c61
--- /dev/null
+++ b/whatwg/css/css-env.json
@@ -0,0 +1,9 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<env()>": {
+      "value": "env( <custom-ident> , <declaration-value>? )"
+    }
+  }
+}
diff --git a/whatwg/css/css-exclusions.json b/whatwg/css/css-exclusions.json
new file mode 100644
index 000000000000..47be99b709f6
--- /dev/null
+++ b/whatwg/css/css-exclusions.json
@@ -0,0 +1,28 @@
+{
+  "properties": {
+    "wrap-flow": {
+      "name": "wrap-flow",
+      "value": "auto | both | start | end | minimum | maximum | clear",
+      "initial": "auto",
+      "appliesTo": "block-level elements.",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified except for element’s whose float computed value is not none, in which case the computed value is auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "wrap-through": {
+      "name": "wrap-through",
+      "value": "wrap | none",
+      "initial": "wrap",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-flexbox.json b/whatwg/css/css-flexbox.json
new file mode 100644
index 000000000000..ffb575044f99
--- /dev/null
+++ b/whatwg/css/css-flexbox.json
@@ -0,0 +1,142 @@
+{
+  "properties": {
+    "display": {
+      "name": "display",
+      "newValues": "flex | inline-flex"
+    },
+    "flex-direction": {
+      "name": "flex-direction",
+      "value": "row | row-reverse | column | column-reverse",
+      "initial": "row",
+      "appliesTo": "flex containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "flex-wrap": {
+      "name": "flex-wrap",
+      "value": "nowrap | wrap | wrap-reverse",
+      "initial": "nowrap",
+      "appliesTo": "flex containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "flex-flow": {
+      "name": "flex-flow",
+      "value": "<‘flex-direction’> || <‘flex-wrap’>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "order": {
+      "name": "order",
+      "value": "<integer>",
+      "initial": "0",
+      "appliesTo": "flex items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "integer"
+    },
+    "flex": {
+      "name": "flex",
+      "value": "none | [ <‘flex-grow’> <‘flex-shrink’>? || <‘flex-basis’> ]",
+      "initial": "0 1 auto",
+      "appliesTo": "flex items",
+      "inherited": "no",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "flex-grow": {
+      "name": "flex-grow",
+      "value": "<number>",
+      "initial": "0",
+      "appliesTo": "flex items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "number"
+    },
+    "flex-shrink": {
+      "name": "flex-shrink",
+      "value": "<number>",
+      "initial": "1",
+      "appliesTo": "flex items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "number"
+    },
+    "flex-basis": {
+      "name": "flex-basis",
+      "value": "content | <‘width’>",
+      "initial": "auto",
+      "appliesTo": "flex items",
+      "inherited": "no",
+      "percentages": "relative to the flex container’s inner main size",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete for keywords, otherwise as length, percentage, or calc"
+    },
+    "justify-content": {
+      "name": "justify-content",
+      "value": "flex-start | flex-end | center | space-between | space-around",
+      "initial": "flex-start",
+      "appliesTo": "flex containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "align-items": {
+      "name": "align-items",
+      "value": "flex-start | flex-end | center | baseline | stretch",
+      "initial": "stretch",
+      "appliesTo": "flex containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "align-self": {
+      "name": "align-self",
+      "value": "auto | flex-start | flex-end | center | baseline | stretch",
+      "initial": "auto",
+      "appliesTo": "flex items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "align-content": {
+      "name": "align-content",
+      "value": "flex-start | flex-end | center | space-between | space-around | stretch",
+      "initial": "stretch",
+      "appliesTo": "multi-line flex containers",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-fonts.json b/whatwg/css/css-fonts.json
new file mode 100644
index 000000000000..3ded8263541c
--- /dev/null
+++ b/whatwg/css/css-fonts.json
@@ -0,0 +1,361 @@
+{
+  "properties": {
+    "font-family": {
+      "name": "font-family",
+      "value": "[ <family-name> | <generic-family> ] #",
+      "initial": "depends on user agent",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "a list of strings and/or <generic-family> keywords",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "font-weight": {
+      "name": "font-weight",
+      "value": "<font-weight-absolute> | bolder | lighter",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "numeric weight value (see description)",
+      "canonicalOrder": "per grammar",
+      "animatable": "As <number>"
+    },
+    "font-stretch": {
+      "name": "font-stretch",
+      "value": "normal | <percentage> | ultra-condensed | extra-condensed | condensed | semi-condensed | semi-expanded | expanded | extra-expanded | ultra-expanded",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "Not resolved",
+      "computedValue": "percentage",
+      "canonicalOrder": "per grammar",
+      "animatable": "As <percentage>"
+    },
+    "font-style": {
+      "name": "font-style",
+      "value": "normal | italic | oblique <angle>?",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "As specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "If both \"from\" and \"to\" values are \"oblique\", then yes, as an <angle>. Otherwise, no."
+    },
+    "font-size": {
+      "name": "font-size",
+      "value": "<absolute-size> | <relative-size> | <length-percentage>",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "refer to parent element’s font size",
+      "computedValue": "an absolute length, as clamped by font-min-size and font-max-size",
+      "canonicalOrder": "per grammar",
+      "animatable": "As <length>"
+    },
+    "font-min-size": {
+      "name": "font-min-size",
+      "value": "<absolute-size> | <relative-size> | <length-percentage>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "refer to parent element’s font size",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animatable": "As <length>"
+    },
+    "font-max-size": {
+      "name": "font-max-size",
+      "value": "<absolute-size> | <relative-size> | <length-percentage> | infinity",
+      "initial": "infinity",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "refer to parent element’s font size",
+      "computedValue": "absolute length",
+      "canonicalOrder": "per grammar",
+      "animatable": "As <length>"
+    },
+    "font-size-adjust": {
+      "name": "font-size-adjust",
+      "value": "none | <number>",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "as <number>"
+    },
+    "font": {
+      "name": "font",
+      "value": "[ [ <‘font-style’> || <font-variant-css2> || <‘font-weight’> || <font-stretch-css3> ]? <‘font-size’> [ / <‘line-height’> ]? <‘font-family’> ] | caption | icon | menu | message-box | small-caption | status-bar",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "see individual properties"
+    },
+    "font-synthesis-weight": {
+      "name": "font-synthesis-weight",
+      "value": "auto | none",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "yes"
+    },
+    "font-synthesis-style": {
+      "name": "font-synthesis-style",
+      "value": "auto | none",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "yes"
+    },
+    "font-synthesis-small-caps": {
+      "name": "font-synthesis-small-caps",
+      "value": "auto | none",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "yes"
+    },
+    "font-synthesis": {
+      "name": "font-synthesis",
+      "value": "none | [ weight || style ]",
+      "initial": "weight style small-caps",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "font-variant-alternates": {
+      "name": "font-variant-alternates",
+      "value": "normal | [ stylistic(<feature-value-name>) || historical-forms || styleset(<feature-value-name>#) || character-variant(<feature-value-name>#) || swash(<feature-value-name>) || ornaments(<feature-value-name>) || annotation(<feature-value-name>) ]",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "font-language-override": {
+      "name": "font-language-override",
+      "value": "normal | <string>",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "font-optical-sizing": {
+      "name": "font-optical-sizing",
+      "value": "auto | none",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "font-variation-settings": {
+      "name": "font-variation-settings",
+      "value": "normal | [ <string> <number>] #",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "yes (see description)"
+    },
+    "font-palette": {
+      "name": "font-palette",
+      "value": "normal | light | dark | <palette-identifier>",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/a",
+      "computedValue": "As specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "No (see below)"
+    },
+    "font-variant-emoji": {
+      "name": "font-variant-emoji",
+      "value": "auto | text | emoji",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/a",
+      "computedValue": "As specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "No (see below)"
+    }
+  },
+  "descriptors": {
+    "font-family": {
+      "name": "font-family",
+      "for": "@font-palette-values",
+      "value": "<‘font-family’>",
+      "initial": "N/A"
+    },
+    "src": {
+      "name": "src",
+      "for": "@font-face",
+      "value": "see prose",
+      "initial": "N/A"
+    },
+    "font-style": {
+      "name": "font-style",
+      "for": "@font-face",
+      "value": "auto | normal | italic | oblique [ <angle> | <angle> <angle> ] ?",
+      "initial": "normal"
+    },
+    "font-weight": {
+      "name": "font-weight",
+      "for": "@font-face",
+      "value": "auto | <font-weight-absolute> <font-weight-absolute>?",
+      "initial": "normal"
+    },
+    "font-stretch": {
+      "name": "font-stretch",
+      "for": "@font-face",
+      "value": "auto | <‘font-stretch’> <‘font-stretch’>?",
+      "initial": "normal"
+    },
+    "unicode-range": {
+      "name": "unicode-range",
+      "for": "@font-face",
+      "value": "<urange> #",
+      "initial": "U+0-10FFFF"
+    },
+    "font-variant": {
+      "name": "font-variant",
+      "for": "@font-face",
+      "value": "normal | none | [ <common-lig-values> || <discretionary-lig-values> || <historical-lig-values> || <contextual-alt-values> || stylistic(<feature-value-name>) || historical-forms || styleset(<feature-value-name>#) || character-variant(<feature-value-name>#) || swash(<feature-value-name>) || ornaments(<feature-value-name>) || annotation(<feature-value-name>) || [ small-caps | all-small-caps | petite-caps | all-petite-caps | unicase | titling-caps ] || <numeric-figure-values> || <numeric-spacing-values> || <numeric-fraction-values> || ordinal || slashed-zero || <east-asian-variant-values> || <east-asian-width-values> || ruby || [ sub | super ] ]",
+      "initial": "normal"
+    },
+    "font-feature-settings": {
+      "name": "font-feature-settings",
+      "for": "@font-face",
+      "value": "normal | <feature-tag-value> #",
+      "initial": "normal"
+    },
+    "font-variation-settings": {
+      "name": "font-variation-settings",
+      "for": "@font-face",
+      "value": "normal | [ <string> <number>] #",
+      "initial": "normal"
+    },
+    "font-named-instance": {
+      "name": "font-named-instance",
+      "for": "@font-face",
+      "value": "auto | <string>",
+      "initial": "auto"
+    },
+    "font-display": {
+      "name": "font-display",
+      "for": "@font-feature-values",
+      "value": "auto | block | swap | fallback | optional",
+      "initial": "auto"
+    },
+    "font-language-override": {
+      "name": "font-language-override",
+      "for": "@font-face",
+      "value": "normal | <string>",
+      "initial": "normal"
+    },
+    "base-palette": {
+      "name": "base-palette",
+      "for": "@font-palette-values",
+      "value": "<integer> | <string>",
+      "initial": "N/A"
+    },
+    "override-color": {
+      "name": "override-color",
+      "for": "@font-palette-values",
+      "value": "[ [ <string> | <integer> ] <color> ]#",
+      "initial": "N/A"
+    }
+  },
+  "valuespaces": {
+    "<font-weight-absolute>": {
+      "value": "[normal | bold | <number>]"
+    },
+    "<font-variant-css2>": {
+      "value": "[normal | small-caps]"
+    },
+    "<font-stretch-css3>": {
+      "value": "[normal | ultra-condensed | extra-condensed | condensed | semi-condensed | semi-expanded | expanded | extra-expanded | ultra-expanded]"
+    },
+    "<font-format>": {
+      "value": "[<string> | woff | truetype | opentype | woff2 | embedded-opentype | svg]"
+    },
+    "<font-technology>": {
+      "value": "[features | variations | color(<color-font-technology>) | palettes]"
+    },
+    "<color-font-technology>": {
+      "value": "[COLR | SVG | sbix]"
+    },
+    "<feature-value-name>": {
+      "value": "<ident>"
+    },
+    "<family-name>": {
+      "prose": "The name of a font family, such as Helvetica or Verdana in the previous example."
+    },
+    "<feature-value-block>": {
+      "value": "<feature-type> { <declaration-list> }"
+    },
+    "<feature-type>": {
+      "value": "@stylistic | @historical-forms | @styleset | @character-variant | @swash | @ornaments | @annotation"
+    },
+    "<feature-value>": {
+      "value": "<integer>+"
+    },
+    "<stylistic()>": {
+      "value": "stylistic(<feature-value-name>)"
+    },
+    "<styleset()>": {
+      "value": "styleset(<feature-value-name>#)"
+    },
+    "<character-variant()>": {
+      "value": "character-variant(<feature-value-name>#)"
+    },
+    "<swash()>": {
+      "value": "swash(<feature-value-name>)"
+    },
+    "<ornaments()>": {
+      "value": "ornaments(<feature-value-name>)"
+    },
+    "<annotation()>": {
+      "value": "annotation(<feature-value-name>)"
+    },
+    "<generic-family>": {
+      "prose": "Each <generic-family> keyword represents a generic font choice, and behaves as an alias for one or more locally-installed fonts belonging to the specified generic font category. A <generic-family> can thus be used as a reliable fallback for when an author’s more specific font choices are not available. Authors are encouraged to append a generic font family as a last alternative for improved robustness. Note that <generic-family> keywords cannot be quoted (otherwise they are interpreted as a <family-name>). The following generic family keywords are defined: serif, sans-serif, cursive, fantasy, monospace, system-ui, emoji, math and fangsong. See §2.1.3 Generic font families."
+    },
+    "<palette-identifier>": {
+      "prose": "This value identifies an author-define palette to use. Users can define a palette by using the @font-palette-values rule. If no applicable @font-palette-values rule is present, this value behaves as normal."
+    }
+  }
+}
diff --git a/whatwg/css/css-gcpm.json b/whatwg/css/css-gcpm.json
new file mode 100644
index 000000000000..cae16803d7bd
--- /dev/null
+++ b/whatwg/css/css-gcpm.json
@@ -0,0 +1,17 @@
+{
+  "properties": {
+    "copy-into": {
+      "name": "copy-into",
+      "value": "none | [ [ <custom-ident> <content-level>] [, <custom-ident> <content-level>]* ]?",
+      "initial": "none",
+      "appliesTo": "all elements and pseudo-elements, but not ::first-line or ::first-letter.",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-grid.json b/whatwg/css/css-grid.json
new file mode 100644
index 000000000000..d11c83b74982
--- /dev/null
+++ b/whatwg/css/css-grid.json
@@ -0,0 +1,35 @@
+{
+  "properties": {
+    "grid-template-rows": {
+      "name": "grid-template-rows",
+      "newValues": "subgrid <line-name-list>?"
+    },
+    "grid-template-columns": {
+      "name": "grid-template-columns",
+      "newValues": "subgrid <line-name-list>?"
+    },
+    "align-content": {
+      "name": "align-content",
+      "newValues": "[ <aspect-ratio> <content-distribution>? ]"
+    },
+    "justify-content": {
+      "name": "justify-content",
+      "newValues": "[ <aspect-ratio> <content-distribution>? ]"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<line-name-list>": {
+      "value": "[ <line-names> | <name-repeat> ]+"
+    },
+    "<line-names>": {
+      "value": "'[' <custom-ident>* ']'"
+    },
+    "<name-repeat>": {
+      "value": "repeat( [ <positive-integer> | auto-fill ], <line-names>+)"
+    },
+    "<aspect-ratio>": {
+      "prose": "A dimension with the unit ar, representing a multiplier against the analogous quantity in the other dimension. If that quantity cannot be determined (e.g. is itself specified as a <aspect-ratio>, or otherwise can’t be referenced), then it is assumed to be zero. Note: This value can expand gutters even when there is no free space left, causing overflow. Specifically, an align-content value of 1ar represents the amount of space (which may be zero) allocated between two adjacent alignment subjects (grid tracks / flex lines / column boxes) by the justify-content property. Unless a different <content-distribution> value is specified, space is distributed according to the same <content-distribution> rules as for justify-content. The behavior of <number> values for justify-content is analogous. Note: The space allocated by align-content: 1ar will be zero if justify-content does not allocate space between adjacent alignment subjects: either due to not having a <content-distribution> value or due to there being fewer than two alignment subjects. If both align-content and justify-content have <number> values, then justify-content’s <number> value is ignored and its <content-distribution> value honored as if specified alone. fIf no <content-distribution> value was specified, then justify-content takes align-content’s <content-distribution> value (if one was specified) and otherwise falls back to space-between."
+    }
+  }
+}
diff --git a/whatwg/css/css-images.json b/whatwg/css/css-images.json
new file mode 100644
index 000000000000..d1447da6a7ca
--- /dev/null
+++ b/whatwg/css/css-images.json
@@ -0,0 +1,81 @@
+{
+  "properties": {
+    "object-fit": {
+      "name": "object-fit",
+      "value": "fill | contain | cover | none | scale-down",
+      "initial": "fill",
+      "appliesTo": "replaced elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "object-position": {
+      "name": "object-position",
+      "value": "<position>",
+      "initial": "50% 50%",
+      "appliesTo": "replaced elements",
+      "inherited": "no",
+      "percentages": "refer to width and height of element itself",
+      "computedValue": "specified value",
+      "canonicalOrder": "the horizontal component of the <position>, followed by the vertical component",
+      "animatable": "yes"
+    },
+    "image-orientation": {
+      "name": "image-orientation",
+      "value": "none | from-image | <angle> | [ <angle>? flip ]",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "the specified keyword, or an <angle>, rounded and normalized (see text), plus optionally a flip keyword",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "image-rendering": {
+      "name": "image-rendering",
+      "value": "auto | smooth | high-quality | crisp-edges | pixelated",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<image>": {
+      "value": "<url> | <cross-fade()> | <gradient>"
+    },
+    "<gradient>": {
+      "value": "<linear-gradient()> | <repeating-linear-gradient()> | <radial-gradient()> | <repeating-radial-gradient()>"
+    },
+    "<linear-gradient()>": {
+      "value": "linear-gradient( [ <angle> | to <side-or-corner> ]? , <color-stop-list> )"
+    },
+    "<side-or-corner>": {
+      "value": "[left | right] || [top | bottom]"
+    },
+    "<color-stop-list>": {
+      "value": "<color-stop>#{2,}"
+    },
+    "<color-stop>": {
+      "value": "<color> <length-percentage>?"
+    },
+    "<radial-gradient()>": {
+      "value": "radial-gradient( [ [ circle || <length> ] [ at <position> ]? , | [ ellipse || <length-percentage>{2} ] [ at <position> ]? , | [ [ circle | ellipse ] || <extent-keyword> ] [ at <position> ]? , | at <position> , ]? <color-stop> [ , <color-stop> ]+ )"
+    },
+    "<extent-keyword>": {
+      "value": "closest-corner | closest-side | farthest-corner | farthest-side"
+    },
+    "<ending-shape>": {
+      "prose": "Can be either circle or ellipse; determines whether the gradient’s ending shape is a circle or an ellipse, respectively. If <ending-shape> is omitted, the ending shape defaults to a circle if the <size> is a single <length>, and to an ellipse otherwise."
+    },
+    "<length>": {
+      "prose": "Gives the radius of the circle explicitly. Negative values are invalid. Note: Percentages are not allowed here; they can only be used to specify the size of an elliptical gradient, not a circular one. This restriction exists because there is are multiple reasonable answers as to which dimension the percentage should be relative to. A future level of this module may provide the ability to size circles with percentages, perhaps with more explicit controls over which dimension is used."
+    }
+  }
+}
diff --git a/whatwg/css/css-inline.json b/whatwg/css/css-inline.json
new file mode 100644
index 000000000000..6eefd2df9a88
--- /dev/null
+++ b/whatwg/css/css-inline.json
@@ -0,0 +1,94 @@
+{
+  "properties": {
+    "dominant-baseline": {
+      "name": "dominant-baseline",
+      "value": "auto | text-bottom | alphabetic | ideographic | middle | central | mathematical | hanging | text-top",
+      "initial": "normal",
+      "appliesTo": "block containers, inline boxes, table rows, table columns, grid containers, and flex containers",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "vertical-align": {
+      "name": "vertical-align",
+      "value": "<‘baseline-shift’> || <‘alignment-baseline’>",
+      "initial": "baseline",
+      "appliesTo": "inline-level boxes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "alignment-baseline": {
+      "name": "alignment-baseline",
+      "value": "baseline | text-bottom | alphabetic | ideographic | middle | central | mathematical | text-top | bottom | center | top",
+      "initial": "baseline",
+      "appliesTo": "inline-level boxes, flex items, grid items, table cells",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "baseline-shift": {
+      "name": "baseline-shift",
+      "value": "<length> | <percentage> | sub | super",
+      "initial": "0",
+      "appliesTo": "inline-level boxes, flex items, grid items",
+      "inherited": "no",
+      "percentages": "refer to the used value of line-height",
+      "computedValue": "absolute length, percentage, or keyword specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "inline-sizing": {
+      "name": "inline-sizing",
+      "value": "normal | stretch",
+      "initial": "normal",
+      "appliesTo": "inline boxes",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "initial-letters": {
+      "name": "initial-letters",
+      "value": "normal | [<number> <integer>?]",
+      "initial": "normal",
+      "appliesTo": "certain inline-level boxes and ::first-letter and inside ::marker boxes (see prose)",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "initial-letters-align": {
+      "name": "initial-letters-align",
+      "value": "border-box? [ alphabetic | ideographic | hebrew | hanging ] | border-box",
+      "initial": "alphabetic",
+      "appliesTo": "certain inline-level boxes and ::first-letter and inside ::marker boxes (see prose)",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "initial-letters-wrap": {
+      "name": "initial-letters-wrap",
+      "value": "none | first | all | grid | <length> | <percentage>",
+      "initial": "none",
+      "appliesTo": "certain inline-level boxes and ::first-letter and inside ::marker boxes (see prose)",
+      "inherited": "yes",
+      "percentages": "relative to logical width of (last fragment of) initial letter",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-line-grid.json b/whatwg/css/css-line-grid.json
new file mode 100644
index 000000000000..fb2a5b1e7807
--- /dev/null
+++ b/whatwg/css/css-line-grid.json
@@ -0,0 +1,39 @@
+{
+  "properties": {
+    "line-grid": {
+      "name": "line-grid",
+      "value": "match-parent | create",
+      "initial": "match-parent",
+      "appliesTo": "block, flex and grid containers",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "line-snap": {
+      "name": "line-snap",
+      "value": "none | baseline | contain",
+      "initial": "none",
+      "appliesTo": "block container elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "box-snap": {
+      "name": "box-snap",
+      "value": "none | block-start | block-end | center | baseline | last-baseline",
+      "initial": "none",
+      "appliesTo": "block-level boxes and internal table elements except table cells",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-lists.json b/whatwg/css/css-lists.json
new file mode 100644
index 000000000000..b58193ee6cd5
--- /dev/null
+++ b/whatwg/css/css-lists.json
@@ -0,0 +1,106 @@
+{
+  "properties": {
+    "list-style-image": {
+      "name": "list-style-image",
+      "value": "<image> | none",
+      "initial": "none",
+      "appliesTo": "list items",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "computed value of the <image>, or none",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "list-style-type": {
+      "name": "list-style-type",
+      "value": "<counter-style> | <string> | none",
+      "initial": "disc",
+      "appliesTo": "list items",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "list-style-position": {
+      "name": "list-style-position",
+      "value": "inside | outside",
+      "initial": "outside",
+      "appliesTo": "list items",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value (but see prose)",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "list-style": {
+      "name": "list-style",
+      "value": "<‘list-style-type’> || <‘list-style-position’> || <‘list-style-image’>",
+      "initial": "see individual properties",
+      "appliesTo": "list items",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "position": {
+      "name": "position",
+      "newValues": "marker",
+      "computedValue": "see prose, otherwise same as normal"
+    },
+    "marker-side": {
+      "name": "marker-side",
+      "value": "list-item | list-container",
+      "initial": "list-item",
+      "appliesTo": "list items",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "counter-reset": {
+      "name": "counter-reset",
+      "value": "[ <custom-ident> <integer>? ]+ | none",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "counter-set": {
+      "name": "counter-set",
+      "value": "[ <custom-ident> <integer>? ]+ | none",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "counter-increment": {
+      "name": "counter-increment",
+      "value": "[ <custom-ident> <integer>? ]+ | none",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<counter()>": {
+      "value": "counter( <custom-ident>, [ <counter-style> | none ]? )"
+    },
+    "<counters()>": {
+      "value": "counters( <custom-ident>, <string>, [ <counter-style> | none ]? )"
+    }
+  }
+}
diff --git a/whatwg/css/css-logical.json b/whatwg/css/css-logical.json
new file mode 100644
index 000000000000..ff0994717edf
--- /dev/null
+++ b/whatwg/css/css-logical.json
@@ -0,0 +1,587 @@
+{
+  "properties": {
+    "caption-side": {
+      "name": "caption-side",
+      "newValues": "inline-start | inline-end"
+    },
+    "float": {
+      "name": "float",
+      "newValues": "inline-start | inline-end"
+    },
+    "clear": {
+      "name": "clear",
+      "newValues": "inline-start | inline-end"
+    },
+    "text-align": {
+      "name": "text-align",
+      "newValues": "start | end"
+    },
+    "resize": {
+      "name": "resize",
+      "newValues": "block | inline"
+    },
+    "block-size": {
+      "name": "block-size",
+      "value": "<‘width’>",
+      "initial": "auto",
+      "appliesTo": "Same as width and height",
+      "inherited": "No",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as width, height",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as width, height"
+    },
+    "inline-size": {
+      "name": "inline-size",
+      "value": "<‘width’>",
+      "initial": "auto",
+      "appliesTo": "Same as width and height",
+      "inherited": "No",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as width, height",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as width, height"
+    },
+    "min-block-size": {
+      "name": "min-block-size",
+      "value": "<‘min-width’>",
+      "initial": "0",
+      "appliesTo": "same as width and height",
+      "inherited": "No",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as min-width, min-height",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as min-width, min-height"
+    },
+    "min-inline-size": {
+      "name": "min-inline-size",
+      "value": "<‘min-width’>",
+      "initial": "0",
+      "appliesTo": "same as width and height",
+      "inherited": "No",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as min-width, min-height",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as min-width, min-height"
+    },
+    "max-block-size": {
+      "name": "max-block-size",
+      "value": "<‘max-width’>",
+      "initial": "none",
+      "appliesTo": "same as width and height",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as max-width, max-height",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as max-width, max-height"
+    },
+    "max-inline-size": {
+      "name": "max-inline-size",
+      "value": "<‘max-width’>",
+      "initial": "none",
+      "appliesTo": "same as width and height",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as max-width, max-height",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as max-width, max-height"
+    },
+    "margin-block-start": {
+      "name": "margin-block-start",
+      "value": "<‘margin-top’>",
+      "initial": "0",
+      "appliesTo": "Same as margin-top",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding margin-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as margin-top"
+    },
+    "margin-block-end": {
+      "name": "margin-block-end",
+      "value": "<‘margin-top’>",
+      "initial": "0",
+      "appliesTo": "Same as margin-top",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding margin-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as margin-top"
+    },
+    "margin-inline-start": {
+      "name": "margin-inline-start",
+      "value": "<‘margin-top’>",
+      "initial": "0",
+      "appliesTo": "Same as margin-top",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding margin-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as margin-top"
+    },
+    "margin-inline-end": {
+      "name": "margin-inline-end",
+      "value": "<‘margin-top’>",
+      "initial": "0",
+      "appliesTo": "Same as margin-top",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding margin-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as margin-top"
+    },
+    "margin-block": {
+      "name": "margin-block",
+      "value": "<‘margin-left’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "margin-inline": {
+      "name": "margin-inline",
+      "value": "<‘margin-left’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "inset-block-start": {
+      "name": "inset-block-start",
+      "value": "<‘top’>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding top/right/bottom/left properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as top"
+    },
+    "inset-block-end": {
+      "name": "inset-block-end",
+      "value": "<‘top’>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding top/right/bottom/left properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as top"
+    },
+    "inset-inline-start": {
+      "name": "inset-inline-start",
+      "value": "<‘top’>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding top/right/bottom/left properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as top"
+    },
+    "inset-inline-end": {
+      "name": "inset-inline-end",
+      "value": "<‘top’>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding top/right/bottom/left properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as top"
+    },
+    "inset-block": {
+      "name": "inset-block",
+      "value": "<‘top’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "inset-inline": {
+      "name": "inset-inline",
+      "value": "<‘top’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "inset": {
+      "name": "inset",
+      "value": "<‘top’>{1,4}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "padding-block-start": {
+      "name": "padding-block-start",
+      "value": "<‘padding-top’>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding padding-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as padding-top"
+    },
+    "padding-block-end": {
+      "name": "padding-block-end",
+      "value": "<‘padding-top’>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding padding-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as padding-top"
+    },
+    "padding-inline-start": {
+      "name": "padding-inline-start",
+      "value": "<‘padding-top’>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding padding-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as padding-top"
+    },
+    "padding-inline-end": {
+      "name": "padding-inline-end",
+      "value": "<‘padding-top’>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "As for the corresponding physical property",
+      "computedValue": "Same as corresponding padding-* properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as padding-top"
+    },
+    "padding-block": {
+      "name": "padding-block",
+      "value": "<‘padding-left’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "padding-inline": {
+      "name": "padding-inline",
+      "value": "<‘padding-left’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-block-start-width": {
+      "name": "border-block-start-width",
+      "value": "<‘border-top-width’>",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-width properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-width"
+    },
+    "border-block-end-width": {
+      "name": "border-block-end-width",
+      "value": "<‘border-top-width’>",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-width properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-width"
+    },
+    "border-inline-start-width": {
+      "name": "border-inline-start-width",
+      "value": "<‘border-top-width’>",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-width properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-width"
+    },
+    "border-inline-end-width": {
+      "name": "border-inline-end-width",
+      "value": "<‘border-top-width’>",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-width properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-width"
+    },
+    "border-block-width": {
+      "name": "border-block-width",
+      "value": "<‘border-top-width’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-inline-width": {
+      "name": "border-inline-width",
+      "value": "<‘border-top-width’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-block-start-style": {
+      "name": "border-block-start-style",
+      "value": "<‘border-top-style’>",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-style properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-style"
+    },
+    "border-block-end-style": {
+      "name": "border-block-end-style",
+      "value": "<‘border-top-style’>",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-style properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-style"
+    },
+    "border-inline-start-style": {
+      "name": "border-inline-start-style",
+      "value": "<‘border-top-style’>",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-style properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-style"
+    },
+    "border-inline-end-style": {
+      "name": "border-inline-end-style",
+      "value": "<‘border-top-style’>",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-style properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-style"
+    },
+    "border-block-style": {
+      "name": "border-block-style",
+      "value": "<‘border-top-style’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-inline-style": {
+      "name": "border-inline-style",
+      "value": "<‘border-top-style’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-block-start-color": {
+      "name": "border-block-start-color",
+      "value": "<‘border-top-color’>",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-color properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-color"
+    },
+    "border-block-end-color": {
+      "name": "border-block-end-color",
+      "value": "<‘border-top-color’>",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-color properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-color"
+    },
+    "border-inline-start-color": {
+      "name": "border-inline-start-color",
+      "value": "<‘border-top-color’>",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-color properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-color"
+    },
+    "border-inline-end-color": {
+      "name": "border-inline-end-color",
+      "value": "<‘border-top-color’>",
+      "initial": "currentcolor",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Same as corresponding border-*-color properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "Same as border-top-color"
+    },
+    "border-block-color": {
+      "name": "border-block-color",
+      "value": "<‘border-top-color’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-inline-color": {
+      "name": "border-inline-color",
+      "value": "<‘border-top-color’>{1,2}",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-block-start": {
+      "name": "border-block-start",
+      "value": "<‘border-top-width’> || <‘border-top-style’> || <color>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-block-end": {
+      "name": "border-block-end",
+      "value": "<‘border-top-width’> || <‘border-top-style’> || <color>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-inline-start": {
+      "name": "border-inline-start",
+      "value": "<‘border-top-width’> || <‘border-top-style’> || <color>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-inline-end": {
+      "name": "border-inline-end",
+      "value": "<‘border-top-width’> || <‘border-top-style’> || <color>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-block": {
+      "name": "border-block",
+      "value": "<‘border-block-start’>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "border-inline": {
+      "name": "border-inline",
+      "value": "<‘border-block-start’>",
+      "initial": "see individual properties",
+      "appliesTo": "see individual properties",
+      "inherited": "see individual properties",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "animationType": "see individual properties",
+      "canonicalOrder": "per grammar"
+    },
+    "background-image-transform": {
+      "name": "background-image-transform",
+      "value": "logical | physical | rotate",
+      "initial": "physical",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "discrete"
+    },
+    "border-image-transform": {
+      "name": "border-image-transform",
+      "value": "logical | physical | rotate",
+      "initial": "rotate",
+      "appliesTo": "All elements, except internal table elements when border-collapse is collapse",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-masking.json b/whatwg/css/css-masking.json
new file mode 100644
index 000000000000..886916abfa75
--- /dev/null
+++ b/whatwg/css/css-masking.json
@@ -0,0 +1,274 @@
+{
+  "properties": {
+    "clip-path": {
+      "name": "clip-path",
+      "value": "<clip-source> | [ <basic-shape> || <geometry-box> ] | none",
+      "initial": "none",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, but with <url> values made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as specified for <basic-shape> [CSS-SHAPES], otherwise no"
+    },
+    "clip-rule": {
+      "name": "clip-rule",
+      "value": "nonzero | evenodd",
+      "initial": "nonzero",
+      "appliesTo": "Applies to SVG graphics elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-image": {
+      "name": "mask-image",
+      "value": "<mask-reference>#",
+      "initial": "none",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, but with URIs made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-mode": {
+      "name": "mask-mode",
+      "value": "<masking-mode>#",
+      "initial": "match-source",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-repeat": {
+      "name": "mask-repeat",
+      "value": "<repeat-style>#",
+      "initial": "repeat",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "Consists of: two keywords, one per dimension",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-position": {
+      "name": "mask-position",
+      "value": "<position>#",
+      "initial": "0% 0%",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "refer to size of mask painting area minus size of mask layer image; see text background-position [CSS3BG]",
+      "computedValue": "Consisting of: two keywords representing the origin and two offsets from that origin, each given as an absolute length (if given a <length>), otherwise as a percentage.",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of simple list of length, percentage, or calc"
+    },
+    "mask-clip": {
+      "name": "mask-clip",
+      "value": "[ <geometry-box> | no-clip ]#",
+      "initial": "border-box",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-origin": {
+      "name": "mask-origin",
+      "value": "<geometry-box>#",
+      "initial": "border-box",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-size": {
+      "name": "mask-size",
+      "value": "<bg-size>#",
+      "initial": "auto",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, but with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of simple list of length, percentage, or calc (This means keyword values are not animatable.)"
+    },
+    "mask-composite": {
+      "name": "mask-composite",
+      "value": "<compositing-operator>#",
+      "initial": "add",
+      "appliesTo": "All elements. In SVG, it applies to container elements without the defs element and all graphics elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask": {
+      "name": "mask",
+      "value": "<mask-layer>#",
+      "initial": "see individual properties",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "see individual properties"
+    },
+    "mask-border-source": {
+      "name": "mask-border-source",
+      "value": "none | <image>",
+      "initial": "none",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "none or the image with its URI made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-border-mode": {
+      "name": "mask-border-mode",
+      "value": "luminance | alpha",
+      "initial": "alpha",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-border-slice": {
+      "name": "mask-border-slice",
+      "value": "<number-percentage>{1,4} fill?",
+      "initial": "0",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "refer to size of the mask border image",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-border-width": {
+      "name": "mask-border-width",
+      "value": "[ <length-percentage> | <number> | auto ]{1,4}",
+      "initial": "auto",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "relative to width/height of the mask border image area",
+      "computedValue": "all <length>s made absolute, otherwise as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-border-outset": {
+      "name": "mask-border-outset",
+      "value": "[ <length> | <number> ]{1,4}",
+      "initial": "0",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "all <length>s made absolute, otherwise as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-border-repeat": {
+      "name": "mask-border-repeat",
+      "value": "[ stretch | repeat | round | space ]{1,2}",
+      "initial": "stretch",
+      "appliesTo": "All elements. In SVG, it applies to container elements excluding the defs element, all graphics elements and the use element",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "mask-border": {
+      "name": "mask-border",
+      "value": "<‘mask-border-source’> || <‘mask-border-slice’> [ / <‘mask-border-width’>? [ / <‘mask-border-outset’> ]? ]? || <‘mask-border-repeat’> || <‘mask-border-mode’>",
+      "initial": "See individual properties",
+      "appliesTo": "See individual properties",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "See individual properties",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "See individual properties"
+    },
+    "mask-type": {
+      "name": "mask-type",
+      "value": "luminance | alpha",
+      "initial": "luminance",
+      "appliesTo": "mask elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "clip": {
+      "name": "clip",
+      "value": "rect() | auto",
+      "initial": "auto",
+      "appliesTo": "Absolutely positioned elements. In SVG, it applies to elements which establish a new viewport, pattern elements and mask elements.",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as rectangle"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<clip-source>": {
+      "value": "<url>"
+    },
+    "<geometry-box>": {
+      "value": "<shape-box> | fill-box | stroke-box | view-box"
+    },
+    "<mask-reference>": {
+      "value": "none | <image> | <mask-source>"
+    },
+    "<mask-source>": {
+      "value": "<url>"
+    },
+    "<masking-mode>": {
+      "value": "alpha | luminance | match-source"
+    },
+    "<compositing-operator>": {
+      "value": "add | subtract | intersect | exclude"
+    },
+    "<mask-layer>": {
+      "value": "<mask-reference> || <position> [ / <bg-size> ]? ||<repeat-style> || <geometry-box> || [ <geometry-box> | no-clip ] || <compositing-operator> || <masking-mode>"
+    },
+    "<rect()>": {
+      "value": "rect( <top>, <right>, <bottom>, <left> )"
+    },
+    "<url>": {
+      "prose": "A URL reference to a mask element (for example url(commonmasks.svg#mask)) or to a CSS image."
+    }
+  }
+}
diff --git a/whatwg/css/css-multicol.json b/whatwg/css/css-multicol.json
new file mode 100644
index 000000000000..2d91ec839b9c
--- /dev/null
+++ b/whatwg/css/css-multicol.json
@@ -0,0 +1,17 @@
+{
+  "properties": {
+    "column-span": {
+      "name": "column-span",
+      "value": "none | <integer> | all | auto",
+      "initial": "none",
+      "appliesTo": "in-flow block-level elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-overflow.json b/whatwg/css/css-overflow.json
new file mode 100644
index 000000000000..474b987d143c
--- /dev/null
+++ b/whatwg/css/css-overflow.json
@@ -0,0 +1,54 @@
+{
+  "properties": {
+    "scrollbar-gutter": {
+      "name": "scrollbar-gutter",
+      "value": "auto | [ stable | always ] && both? && force?",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "text-overflow": {
+      "name": "text-overflow",
+      "value": "[ clip | ellipsis | <string> | fade | <fade()> ]{1,2}",
+      "initial": "clip",
+      "appliesTo": "block containers",
+      "inherited": "no",
+      "percentages": "refer to the width of the line box",
+      "computedValue": "As specified, with <length> converted to absolute units",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "continue": {
+      "name": "continue",
+      "value": "auto | overflow | paginate | fragments | discard",
+      "initial": "auto",
+      "appliesTo": "block containers [CSS21], flex containers [CSS3-FLEXBOX], and grid containers [CSS3-GRID-LAYOUT]",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "see below",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "max-lines": {
+      "name": "max-lines",
+      "value": "none | <integer>",
+      "initial": "none",
+      "appliesTo": "fragment boxes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "as integer"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<fade()>": {
+      "value": "fade( <length> | <percentage> )"
+    }
+  }
+}
diff --git a/whatwg/css/css-page-floats.json b/whatwg/css/css-page-floats.json
new file mode 100644
index 000000000000..bd7e451bfaba
--- /dev/null
+++ b/whatwg/css/css-page-floats.json
@@ -0,0 +1,68 @@
+{
+  "properties": {
+    "float-reference": {
+      "name": "float-reference",
+      "value": "inline | column | region | page",
+      "initial": "inline",
+      "appliesTo": "all elements.",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified.",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "float": {
+      "name": "float",
+      "value": "block-start | block-end | inline-start | inline-end | snap-block | <snap-block()> | snap-inline | <snap-inline()> | left | right | top | bottom | none",
+      "initial": "none",
+      "appliesTo": "all elements.",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified.",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "clear": {
+      "name": "clear",
+      "value": "inline-start | inline-end | block-start | block-end | left | right | top | bottom | none",
+      "initial": "none",
+      "appliesTo": "block-level elements, floats, regions, pages",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified.",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "float-defer": {
+      "name": "float-defer",
+      "value": "<integer> | last | none",
+      "initial": "none",
+      "appliesTo": "floats",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified.",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "float-offset": {
+      "name": "float-offset",
+      "value": "<length> | <percentage>",
+      "initial": "0",
+      "appliesTo": "floats",
+      "inherited": "no",
+      "percentages": "see prose",
+      "computedValue": "one absolute length",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<snap-block()>": {
+      "value": "snap-block()"
+    },
+    "<snap-inline()>": {
+      "value": "snap-inline()"
+    }
+  }
+}
diff --git a/whatwg/css/css-page.json b/whatwg/css/css-page.json
new file mode 100644
index 000000000000..73fcaf857360
--- /dev/null
+++ b/whatwg/css/css-page.json
@@ -0,0 +1,52 @@
+{
+  "properties": {
+    "page": {
+      "name": "page",
+      "value": "auto | <custom-ident>",
+      "initial": "auto",
+      "appliesTo": "boxes that create class A break points",
+      "inherited": "no (but see prose)",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {
+    "size": {
+      "name": "size",
+      "for": "@page",
+      "value": "<length>{1,2} | auto | [ <page-size> || [ portrait | landscape ] ]",
+      "initial": "auto",
+      "computedValue": "specified value, with <length>s made absolute."
+    },
+    "marks": {
+      "name": "marks",
+      "for": "@page",
+      "value": "none | [ crop || cross ]",
+      "initial": "none",
+      "computedValue": "as specified"
+    },
+    "bleed": {
+      "name": "bleed",
+      "for": "@page",
+      "value": "auto | <length>",
+      "initial": "auto",
+      "computedValue": "as specified"
+    }
+  },
+  "valuespaces": {
+    "<page-selector-list>": {
+      "value": "<page-selector>#"
+    },
+    "<page-selector>": {
+      "value": "[ <ident-token>? <pseudo-page>* ]!"
+    },
+    "<pseudo-page>": {
+      "value": "':' [ left | right | first | blank ] /* Margin rules */"
+    },
+    "<page-size>": {
+      "prose": "A page size can be specified using one of the following media names. This is the equivalent of specifying size using length values. The definition of the the media names comes from Media Standardized Names [PWGMSN]. A5 Equivalent to the size of ISO A5 media: 148mm wide and 210 mm high. A4 Equivalent to the size of ISO A4 media: 210 mm wide and 297 mm high. A3 Equivalent to the size of ISO A3 media: 297mm wide and 420mm high. B5 Equivalent to the size of ISO B5 media: 176mm wide by 250mm high. B4 Equivalent to the size of ISO B4 media: 250mm wide by 353mm high. JIS-B5 Equivalent to the size of JIS B5 media: 182mm wide by 257mm high. JIS-B4 Equivalent to the size of JIS B4 media: 257mm wide by 364mm high. letter Equivalent to the size of North American letter media: 8.5 inches wide and 11 inches high legal Equivalent to the size of North American legal: 8.5 inches wide by 14 inches high. ledger Equivalent to the size of North American ledger: 11 inches wide by 17 inches high."
+    }
+  }
+}
diff --git a/whatwg/css/css-position.json b/whatwg/css/css-position.json
new file mode 100644
index 000000000000..047631dd81cf
--- /dev/null
+++ b/whatwg/css/css-position.json
@@ -0,0 +1,126 @@
+{
+  "properties": {
+    "position": {
+      "name": "position",
+      "value": "static | relative | absolute | sticky | fixed",
+      "initial": "static",
+      "appliesTo": "all elements except table-column-group and table-column",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "top": {
+      "name": "top",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a '<length>', the corresponding absolute length; if specified as a '<percentage>', the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "right": {
+      "name": "right",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a '<length>', the corresponding absolute length; if specified as a '<percentage>', the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "bottom": {
+      "name": "bottom",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a '<length>', the corresponding absolute length; if specified as a '<percentage>', the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "left": {
+      "name": "left",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a '<length>', the corresponding absolute length; if specified as a '<percentage>', the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "offset-before": {
+      "name": "offset-before",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a <length>, the corresponding absolute length; if specified as a <percentage>, the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "offset-after": {
+      "name": "offset-after",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a <length>, the corresponding absolute length; if specified as a <percentage>, the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "offset-start": {
+      "name": "offset-start",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a <length>, the corresponding absolute length; if specified as a <percentage>, the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "offset-end": {
+      "name": "offset-end",
+      "value": "auto | <length-percentage>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "refer to height of containing block",
+      "computedValue": "For position: relative, see Relative positioning. For position: sticky, see Sticky positioning. For position: static, auto. Otherwise: if specified as a <length>, the corresponding absolute length; if specified as a <percentage>, the specified value; otherwise, auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length or percentage"
+    },
+    "z-index": {
+      "name": "z-index",
+      "value": "auto | <integer>",
+      "initial": "auto",
+      "appliesTo": "positioned elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "<integer>"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<length>": {
+      "prose": "The offset is a fixed distance from the reference edge. Negative values are allowed."
+    },
+    "<percentage>": {
+      "prose": "The offset is a percentage of the containing block’s width (for left or right) or height (for top and bottom). For stickily positioned elements, the offset is a percentage of the flow root’s width (for left or right) or height (for top or bottom). Negative values are allowed."
+    },
+    "<integer>": {
+      "prose": "This integer is the stack level of the generated box in the current stacking context. The box also establishes a new stacking context."
+    }
+  }
+}
diff --git a/whatwg/css/css-regions.json b/whatwg/css/css-regions.json
new file mode 100644
index 000000000000..6c3518b1a9af
--- /dev/null
+++ b/whatwg/css/css-regions.json
@@ -0,0 +1,72 @@
+{
+  "properties": {
+    "flow-into": {
+      "name": "flow-into",
+      "value": "none | <ident> [element|content]?",
+      "initial": "none",
+      "appliesTo": "All elements, but not pseudo-elements such as ::first-line, ::first-letter, ::before or ::after.",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "flow-from": {
+      "name": "flow-from",
+      "value": "<ident> | none | inherit",
+      "initial": "none",
+      "appliesTo": "Non-replaced block containers. This might be expanded in future versions of the specification to allow other types of containers to receive flow content.",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "break-before": {
+      "name": "break-before",
+      "value": "auto | always | avoid | left | right | page | column | region | avoid-page | avoid-column | avoid-region",
+      "initial": "auto",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "break-after": {
+      "name": "break-after",
+      "value": "auto | always | avoid | left | right | page | column | region | avoid-page | avoid-column | avoid-region",
+      "initial": "auto",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "break-inside": {
+      "name": "break-inside",
+      "value": "auto | avoid | avoid-page | avoid-column | avoid-region",
+      "initial": "auto",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "region-fragment": {
+      "name": "region-fragment",
+      "value": "auto | break",
+      "initial": "auto",
+      "appliesTo": "CSS Regions",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-rhythm.json b/whatwg/css/css-rhythm.json
new file mode 100644
index 000000000000..db6b4c00f1ab
--- /dev/null
+++ b/whatwg/css/css-rhythm.json
@@ -0,0 +1,72 @@
+{
+  "properties": {
+    "block-step-size": {
+      "name": "block-step-size",
+      "value": "none | <length>",
+      "initial": "none",
+      "appliesTo": "block-level boxes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "keyword or absolute length",
+      "canonicalOrder": "per grammar",
+      "animatable": "???"
+    },
+    "block-step-insert": {
+      "name": "block-step-insert",
+      "value": "margin | padding",
+      "initial": "margin",
+      "appliesTo": "block-level boxes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "block-step-align": {
+      "name": "block-step-align",
+      "value": "auto | center | start | end",
+      "initial": "auto",
+      "appliesTo": "block-level boxes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "block-step-round": {
+      "name": "block-step-round",
+      "value": "up | down | nearest",
+      "initial": "up",
+      "appliesTo": "block-level boxes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "block-step": {
+      "name": "block-step",
+      "value": "<‘block-step-size’> || <‘block-step-insert’> || <‘block-step-align’> || <‘block-step-round’>",
+      "initial": "See individual properties",
+      "appliesTo": "block-level boxes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "See individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "See individual properties"
+    },
+    "line-height-step": {
+      "name": "line-height-step",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "the absolute length",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-round-display.json b/whatwg/css/css-round-display.json
new file mode 100644
index 000000000000..9b4615c7fd89
--- /dev/null
+++ b/whatwg/css/css-round-display.json
@@ -0,0 +1,43 @@
+{
+  "properties": {
+    "shape-inside": {
+      "name": "shape-inside",
+      "value": "auto | outside-shape | [ <basic-shape> || shape-box ] | <image> | display",
+      "initial": "auto",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "computed lengths for <basic-shape>, the absolute URI for <uri>, otherwise as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "as specified for <basic-shape>, otherwise no"
+    },
+    "border-boundary": {
+      "name": "border-boundary",
+      "value": "none | parent | display",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {
+    "shape": {
+      "name": "shape",
+      "for": "@media",
+      "value": "rect | round",
+      "type": "discrete"
+    },
+    "viewport-fit": {
+      "name": "viewport-fit",
+      "for": "@viewport",
+      "value": "auto | contain | cover",
+      "initial": "auto",
+      "percentages": "N/A",
+      "computedValue": "as specified"
+    }
+  },
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-ruby.json b/whatwg/css/css-ruby.json
new file mode 100644
index 000000000000..8736ba4db8d4
--- /dev/null
+++ b/whatwg/css/css-ruby.json
@@ -0,0 +1,43 @@
+{
+  "properties": {
+    "display": {
+      "name": "display",
+      "newValues": "ruby | ruby-base | ruby-text | ruby-base-container | ruby-text-container"
+    },
+    "ruby-position": {
+      "name": "ruby-position",
+      "value": "over | under | inter-character",
+      "initial": "over",
+      "appliesTo": "ruby annotation containers",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "ruby-merge": {
+      "name": "ruby-merge",
+      "value": "separate | collapse | auto",
+      "initial": "separate",
+      "appliesTo": "ruby annotation containers",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "ruby-align": {
+      "name": "ruby-align",
+      "value": "start | center | space-between | space-around",
+      "initial": "space-around",
+      "appliesTo": "ruby bases, ruby annotations, ruby base containers, ruby annotation containers",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-scroll-anchoring.json b/whatwg/css/css-scroll-anchoring.json
new file mode 100644
index 000000000000..646262873b09
--- /dev/null
+++ b/whatwg/css/css-scroll-anchoring.json
@@ -0,0 +1,17 @@
+{
+  "properties": {
+    "overflow-anchor": {
+      "name": "overflow-anchor",
+      "value": "auto | none",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-scroll-snap.json b/whatwg/css/css-scroll-snap.json
new file mode 100644
index 000000000000..749882e20b51
--- /dev/null
+++ b/whatwg/css/css-scroll-snap.json
@@ -0,0 +1,281 @@
+{
+  "properties": {
+    "scroll-snap-type": {
+      "name": "scroll-snap-type",
+      "value": "none | [ x | y | block | inline | both ] [ mandatory | proximity ]?",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "scroll-padding": {
+      "name": "scroll-padding",
+      "value": "[ <length-percentage> | auto ]{1,4}",
+      "initial": "auto",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the corresponding dimension of the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-margin": {
+      "name": "scroll-margin",
+      "value": "<length>{1,4}",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-snap-align": {
+      "name": "scroll-snap-align",
+      "value": "[ none | start | end | center ]{1,2}",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "two keywords",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "scroll-snap-stop": {
+      "name": "scroll-snap-stop",
+      "value": "normal | always",
+      "initial": "normal",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "scroll-padding-top": {
+      "name": "scroll-padding-top",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-right": {
+      "name": "scroll-padding-right",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-bottom": {
+      "name": "scroll-padding-bottom",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-left": {
+      "name": "scroll-padding-left",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-inline-start": {
+      "name": "scroll-padding-inline-start",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-block-start": {
+      "name": "scroll-padding-block-start",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-inline-end": {
+      "name": "scroll-padding-inline-end",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-block-end": {
+      "name": "scroll-padding-block-end",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "scroll containers",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-block": {
+      "name": "scroll-padding-block",
+      "value": "<length-percentage>{1,2}",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-padding-inline": {
+      "name": "scroll-padding-inline",
+      "value": "<length-percentage>{1,2}",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "relative to the scroll container’s scrollport",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    },
+    "scroll-margin-top": {
+      "name": "scroll-margin-top",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-right": {
+      "name": "scroll-margin-right",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-bottom": {
+      "name": "scroll-margin-bottom",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-left": {
+      "name": "scroll-margin-left",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-block-start": {
+      "name": "scroll-margin-block-start",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-inline-start": {
+      "name": "scroll-margin-inline-start",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-block-end": {
+      "name": "scroll-margin-block-end",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-inline-end": {
+      "name": "scroll-margin-inline-end",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-block": {
+      "name": "scroll-margin-block",
+      "value": "<length>{1,2}",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "scroll-margin-inline": {
+      "name": "scroll-margin-inline",
+      "value": "<length>{1,2}",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-scrollbars.json b/whatwg/css/css-scrollbars.json
new file mode 100644
index 000000000000..1a19e0664421
--- /dev/null
+++ b/whatwg/css/css-scrollbars.json
@@ -0,0 +1,39 @@
+{
+  "properties": {
+    "scrollbar-face-color": {
+      "name": "scrollbar-face-color",
+      "value": "auto | <color>",
+      "initial": "auto",
+      "appliesTo": "boxes to which overflow applies",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "the computed color or the keyword auto",
+      "canonicalOrder": "per grammar",
+      "animationType": "color"
+    },
+    "scrollbar-track-color": {
+      "name": "scrollbar-track-color",
+      "value": "auto | <color>",
+      "initial": "auto",
+      "appliesTo": "boxes to which overflow applies",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "the computed color or the keyword auto",
+      "canonicalOrder": "per grammar",
+      "animationType": "color"
+    },
+    "scrollbar-width": {
+      "name": "scrollbar-width",
+      "value": "auto | thin | <length>",
+      "initial": "auto",
+      "appliesTo": "boxes to which overflow applies",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "absolute length or the keyword auto.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-shadow-parts.json b/whatwg/css/css-shadow-parts.json
new file mode 100644
index 000000000000..f6be40493cac
--- /dev/null
+++ b/whatwg/css/css-shadow-parts.json
@@ -0,0 +1,12 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<::part()>": {
+      "value": "::part( <ident> )"
+    },
+    "<::theme()>": {
+      "value": "::theme( <ident> )"
+    }
+  }
+}
diff --git a/whatwg/css/css-shapes.json b/whatwg/css/css-shapes.json
new file mode 100644
index 000000000000..9063f0b53f22
--- /dev/null
+++ b/whatwg/css/css-shapes.json
@@ -0,0 +1,38 @@
+{
+  "properties": {
+    "shape-inside": {
+      "name": "shape-inside",
+      "value": "auto | outside-shape | [ <basic-shape> || shape-box ] | <image> | display",
+      "initial": "auto",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "computed lengths for <basic-shape>, the absolute URI for <uri>, otherwise as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "as specified for <basic-shape>, otherwise no"
+    },
+    "shape-padding": {
+      "name": "shape-padding",
+      "value": "<length>",
+      "initial": "none",
+      "appliesTo": "block-level elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "the absolute length",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length, percentage, or calc"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<path()>": {
+      "value": "path( [<fill-rule>,]? <string> )"
+    },
+    "<basic-shape>": {
+      "prose": "The shape is computed based on the values of one of inset(), circle(), ellipse() or polygon()."
+    },
+    "<uri>": {
+      "prose": "If the <uri> references an SVG shape element, that element defines the shape. Otherwise, if the <uri> references an image, the shape is extracted and computed based on the alpha channel of the specified image. If the <uri> does not reference an SVG shape element or an image, the effect is as if the value auto had been specified."
+    }
+  }
+}
diff --git a/whatwg/css/css-size-adjust.json b/whatwg/css/css-size-adjust.json
new file mode 100644
index 000000000000..ba70d343ccf6
--- /dev/null
+++ b/whatwg/css/css-size-adjust.json
@@ -0,0 +1,21 @@
+{
+  "properties": {
+    "text-size-adjust": {
+      "name": "text-size-adjust",
+      "value": "auto | none | <percentage>",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "see below",
+      "computedValue": "as specified",
+      "canonicalOrder": "N/A",
+      "animatable": "as percentage"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<percentage>": {
+      "prose": "When displaying on a small device, renderers must not do size adjustment but instead the computed value of font-size must be multiplied by this percentage. Note: This means that 'text-size-adjust: 100%;' is equivalent to 'text-size-adjust: none;'."
+    }
+  }
+}
diff --git a/whatwg/css/css-syntax.json b/whatwg/css/css-syntax.json
new file mode 100644
index 000000000000..38293fa7ca92
--- /dev/null
+++ b/whatwg/css/css-syntax.json
@@ -0,0 +1,15 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<an+b>": {
+      "value": "odd | even | <integer> | <n-dimension> | '+'? n | -n | <ndashdigit-dimension> | '+'? <ndashdigit-ident> | <dashndashdigit-ident> | <n-dimension> <signed-integer> | '+'? n <signed-integer> | -n <signed-integer> | <ndash-dimension> <signless-integer> | '+'? n- <signless-integer> | -n- <signless-integer> | <n-dimension> ['+' | '-'] <signless-integer> '+'? n ['+' | '-'] <signless-integer> | -n ['+' | '-'] <signless-integer>"
+    },
+    "<urange>": {
+      "value": "u '+' <ident-token> '?'* | u <dimension-token> '?'* | u <number-token> '?'* | u <number-token> <dimension-token> | u <number-token> <number-token> | u '+' '?'+"
+    },
+    "<EOF-token>": {
+      "prose": "A conceptual token representing the end of the list of tokens. Whenever the list of tokens is empty, the next input token is always an <EOF-token>."
+    }
+  }
+}
diff --git a/whatwg/css/css-tables.json b/whatwg/css/css-tables.json
new file mode 100644
index 000000000000..ded491ca8802
--- /dev/null
+++ b/whatwg/css/css-tables.json
@@ -0,0 +1,61 @@
+{
+  "properties": {
+    "table-layout": {
+      "name": "table-layout",
+      "value": "auto | fixed",
+      "initial": "auto",
+      "appliesTo": "table-root boxes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-collapse": {
+      "name": "border-collapse",
+      "value": "separate | collapse",
+      "initial": "separate",
+      "appliesTo": "table-root boxes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "border-spacing": {
+      "name": "border-spacing",
+      "value": "<​length​>{1,2}",
+      "initial": "0px 0px",
+      "appliesTo": "table-root boxes when border-collapse is separate",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "two absolute lengths",
+      "canonicalOrder": "per grammar",
+      "animatable": "yes"
+    },
+    "caption-side": {
+      "name": "caption-side",
+      "value": "top | bottom",
+      "initial": "top",
+      "appliesTo": "table-caption boxes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "empty-cells": {
+      "name": "empty-cells",
+      "value": "show | hide",
+      "initial": "show",
+      "appliesTo": "table-cell boxes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-text-decor.json b/whatwg/css/css-text-decor.json
new file mode 100644
index 000000000000..2a4bf6f99024
--- /dev/null
+++ b/whatwg/css/css-text-decor.json
@@ -0,0 +1,72 @@
+{
+  "properties": {
+    "text-decoration-line": {
+      "name": "text-decoration-line",
+      "value": "none | [ underline || overline || line-through || blink ] | spelling-error | grammar-error",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no (but see prose, above)",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "text-decoration-width": {
+      "name": "text-decoration-width",
+      "value": "auto | from-font | <length>",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "text-underline-offset": {
+      "name": "text-underline-offset",
+      "value": "auto | from-font | <length>",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "text-decoration-skip": {
+      "name": "text-decoration-skip",
+      "value": "none | [ objects || [ spaces | [ leading-spaces || trailing-spaces ] ] || edges || box-decoration ]",
+      "initial": "objects leading-spaces trailing-spaces",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "text-decoration-skip-ink": {
+      "name": "text-decoration-skip-ink",
+      "value": "auto | none",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "text-emphasis-skip": {
+      "name": "text-emphasis-skip",
+      "value": "spaces || punctuation || symbols || narrow",
+      "initial": "spaces punctuation",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/css-text.json b/whatwg/css/css-text.json
new file mode 100644
index 000000000000..6016f392b2e6
--- /dev/null
+++ b/whatwg/css/css-text.json
@@ -0,0 +1,151 @@
+{
+  "properties": {
+    "text-space-collapse": {
+      "name": "text-space-collapse",
+      "value": "collapse | discard | preserve | preserve-breaks | preserve-spaces",
+      "initial": "collapse",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "text-space-trim": {
+      "name": "text-space-trim",
+      "value": "none | trim-inner || discard-before || discard-after",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "text-wrap": {
+      "name": "text-wrap",
+      "value": "wrap | nowrap | balance | multi-line",
+      "initial": "wrap",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "wrap-before": {
+      "name": "wrap-before",
+      "value": "auto | avoid | avoid-line | avoid-flex | line | flex",
+      "initial": "auto",
+      "appliesTo": "inline-level boxes and flex items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "wrap-after": {
+      "name": "wrap-after",
+      "value": "auto | avoid | avoid-line | avoid-flex | line | flex",
+      "initial": "auto",
+      "appliesTo": "inline-level boxes and flex items",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "wrap-inside": {
+      "name": "wrap-inside",
+      "value": "auto | avoid",
+      "initial": "auto",
+      "appliesTo": "inline boxes",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "white-space": {
+      "name": "white-space",
+      "value": "normal | pre | nowrap | pre-wrap | pre-line",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "hyphenate-character": {
+      "name": "hyphenate-character",
+      "value": "auto | <string>",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "hyphenate-limit-zone": {
+      "name": "hyphenate-limit-zone",
+      "value": "<percentage> | <length>",
+      "initial": "0",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "refers to width of the line box",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "hyphenate-limit-chars": {
+      "name": "hyphenate-limit-chars",
+      "value": "[ auto | <integer> ]{1,3}",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "hyphenate-limit-lines": {
+      "name": "hyphenate-limit-lines",
+      "value": "no-limit | <integer>",
+      "initial": "no-limit",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "hyphenate-limit-last": {
+      "name": "hyphenate-limit-last",
+      "value": "none | always | column | page | spread",
+      "initial": "none",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "text-spacing": {
+      "name": "text-spacing",
+      "value": "normal | none | [ trim-start | space-start ] || [ trim-end | space-end | allow-end ] || [ trim-adjacent | space-adjacent ] || no-compress || ideograph-alpha || ideograph-numeric || punctuation",
+      "initial": "normal",
+      "appliesTo": "block containers",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computed value": "specified value"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<string>": {
+      "prose": "The string must be a single character; otherwise the declaration must be ignored. When applied to a table cell, specifies the alignment character around which the cell’s contents will align. See below for further details and how this value combines with keywords."
+    }
+  }
+}
diff --git a/whatwg/css/css-timing.json b/whatwg/css/css-timing.json
new file mode 100644
index 000000000000..048fa77ff2cd
--- /dev/null
+++ b/whatwg/css/css-timing.json
@@ -0,0 +1,24 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<cubic-bezier()>": {
+      "value": "cubic-bezier(<number>, <number>, <number>, <number>)"
+    },
+    "<steps()>": {
+      "value": "steps(<integer>[, [ start | end ] ]?)"
+    },
+    "<timing-function>": {
+      "value": "linear | <cubic-bezier-timing-function> | <step-timing-function> | <frames-timing-function>"
+    },
+    "<cubic-bezier-timing-function>": {
+      "value": "ease | ease-in | ease-out | ease-in-out | cubic-bezier(<number>, <number>, <number>, <number>)"
+    },
+    "<step-timing-function>": {
+      "value": "step-start | step-end | steps(<integer>[, [ start | end ] ]?)"
+    },
+    "<frames-timing-function>": {
+      "value": "frames(<integer>)"
+    }
+  }
+}
diff --git a/whatwg/css/css-transforms.json b/whatwg/css/css-transforms.json
new file mode 100644
index 000000000000..200e20e5f1f5
--- /dev/null
+++ b/whatwg/css/css-transforms.json
@@ -0,0 +1,114 @@
+{
+  "properties": {
+    "translate": {
+      "name": "translate",
+      "value": "none | <length-percentage> [ <length-percentage> <length>? ]?",
+      "initial": "none",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "relative to the width of the containing block (for the first value) or the height (for the second value)",
+      "computedValue": "as specified, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "animatable": "as <length> or <percentage> list"
+    },
+    "rotate": {
+      "name": "rotate",
+      "value": "none | [ x | y | z | <number>{3} ]? && <angle>",
+      "initial": "none",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "as SLERP"
+    },
+    "scale": {
+      "name": "scale",
+      "value": "none | <number>{1,3}",
+      "initial": "none",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "as <number> list"
+    },
+    "transform-style": {
+      "name": "transform-style",
+      "value": "auto | flat | preserve-3d",
+      "initial": "auto",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "Same as specified value.",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "perspective": {
+      "name": "perspective",
+      "value": "none | <length>",
+      "initial": "none",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "Absolute length or \"none\".",
+      "canonicalOrder": "per grammar",
+      "animatable": "as length"
+    },
+    "perspective-origin": {
+      "name": "perspective-origin",
+      "value": "<position>",
+      "initial": "50% 50%",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "refer to the size of the reference box",
+      "computedValue": "For <length> the absolute value, otherwise a percentage.",
+      "canonicalOrder": "per grammar",
+      "animatable": "as simple list of length, percentage, or calc"
+    },
+    "backface-visibility": {
+      "name": "backface-visibility",
+      "value": "visible | hidden",
+      "initial": "visible",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "Same as specified value.",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<matrix3d()>": {
+      "value": "matrix3d( <number> [, <number> ]{15,15} )"
+    },
+    "<translate3d()>": {
+      "value": "translate3d( <length-percentage> , <length-percentage> , <length> )"
+    },
+    "<translateZ()>": {
+      "value": "translateZ( <length> )"
+    },
+    "<scale3d()>": {
+      "value": "scale3d( <number> , <number>, <number> )"
+    },
+    "<scaleZ()>": {
+      "value": "scaleZ( <number> )"
+    },
+    "<rotate3d()>": {
+      "value": "rotate3d( <number> , <number> , <number> , [ <angle> | <zero> ] )"
+    },
+    "<rotateX()>": {
+      "value": "rotateX( [ <angle> | <zero> ] )"
+    },
+    "<rotateY()>": {
+      "value": "rotateY( [ <angle> | <zero> ] )"
+    },
+    "<rotateZ()>": {
+      "value": "rotateZ( [ <angle> | <zero> ] )"
+    },
+    "<perspective()>": {
+      "value": "perspective( <length> )"
+    }
+  }
+}
diff --git a/whatwg/css/css-ui.json b/whatwg/css/css-ui.json
new file mode 100644
index 000000000000..0f00db12ddf5
--- /dev/null
+++ b/whatwg/css/css-ui.json
@@ -0,0 +1,189 @@
+{
+  "properties": {
+    "outline": {
+      "name": "outline",
+      "value": "[ <‘outline-color’> || <‘outline-style’> || <‘outline-width’> ]",
+      "initial": "see individual properties",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animationType": "see individual properties"
+    },
+    "outline-width": {
+      "name": "outline-width",
+      "value": "<line-width>",
+      "initial": "medium",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "absolute length; 0 if the outline style is none.",
+      "canonicalOrder": "per grammar",
+      "animationType": "length"
+    },
+    "outline-style": {
+      "name": "outline-style",
+      "value": "auto | <outline-line-style>",
+      "initial": "none",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "outline-color": {
+      "name": "outline-color",
+      "value": "<color> | invert",
+      "initial": "invert",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "The computed value for invert is invert. For <color> values, see resolving color values in [CSS-COLOR-4].",
+      "canonicalOrder": "per grammar",
+      "animationType": "color"
+    },
+    "outline-offset": {
+      "name": "outline-offset",
+      "value": "<length>",
+      "initial": "0",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "<length> value in absolute units (px or physical).",
+      "canonicalOrder": "per grammar",
+      "animationType": "length"
+    },
+    "resize": {
+      "name": "resize",
+      "value": "none | both | horizontal | vertical",
+      "initial": "none",
+      "appliesTo": "elements with overflow other than visible, and optionally replaced elements such as images, videos, and iframes",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "cursor": {
+      "name": "cursor",
+      "value": "[ [<url> [<x> <y>]?,]* [ auto | default | none | context-menu | help | pointer | progress | wait | cell | crosshair | text | vertical-text | alias | copy | move | no-drop | not-allowed | grab | grabbing | e-resize | n-resize | ne-resize | nw-resize | s-resize | se-resize | sw-resize | w-resize | ew-resize | ns-resize | nesw-resize | nwse-resize | col-resize | row-resize | all-scroll | zoom-in | zoom-out ] ]",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified, except with any relative URLs converted to absolute",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "caret-color": {
+      "name": "caret-color",
+      "value": "auto | <color>",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "The computed value for auto is auto. For <color> values, see resolving color values in [CSS-COLOR-4].",
+      "canonicalOrder": "per grammar",
+      "animationType": "color"
+    },
+    "caret-shape": {
+      "name": "caret-shape",
+      "value": "auto | bar | block | underscore",
+      "initial": "auto",
+      "appliesTo": "elements that accept input",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "Same as specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "caret": {
+      "name": "caret",
+      "value": "<‘caret-color’> || <‘caret-shape’>",
+      "initial": "auto",
+      "appliesTo": "elements that accept input",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "See individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "See individual properties"
+    },
+    "nav-up": {
+      "name": "nav-up",
+      "value": "auto | <id> [ current | root | <target-name> ]?",
+      "initial": "auto",
+      "appliesTo": "all enabled elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "nav-right": {
+      "name": "nav-right",
+      "value": "auto | <id> [ current | root | <target-name> ]?",
+      "initial": "auto",
+      "appliesTo": "all enabled elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "nav-down": {
+      "name": "nav-down",
+      "value": "auto | <id> [ current | root | <target-name> ]?",
+      "initial": "auto",
+      "appliesTo": "all enabled elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "nav-left": {
+      "name": "nav-left",
+      "value": "auto | <id> [ current | root | <target-name> ]?",
+      "initial": "auto",
+      "appliesTo": "all enabled elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "user-select": {
+      "name": "user-select",
+      "value": "auto | text | none | contain | all",
+      "initial": "auto",
+      "appliesTo": "all elements, and optionally to the ::before and ::after pseudo elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "See below",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    },
+    "appearance": {
+      "name": "appearance",
+      "value": "auto | none",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "As specified",
+      "canonicalOrder": "per grammar",
+      "animationType": "discrete"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<id>": {
+      "prose": "The <id> value is an ID selector [SELECT]. In response to directional navigation input corresponding to the property, the focus is navigated to the first element in tree order matching the selector. If this refers to the currently focused element, the directional navigation input respective to the nav- property is ignored — there is no need to refocus the same element. If no element matches the selector, the user agent automatically determines which element to navigate the focus to. If the focus is navigated to an element that was not otherwise focusable, it becomes focusable only as the result of this directional navigation, and the :focus pseudo-class matches the element while it is focused as such. Note: there were other options under consideration for such \"not otherwise focusable\" elements, including focus to the next otherwise focusable element in the document tree (including descendants of such a not otherwise focusable element). Input on such other options is welcome and explicitly solicited, especially from implementation experiences and author experience using the directional navigation properties in their content."
+    },
+    "<target-name>": {
+      "prose": "The <target-name> parameter indicates the target frame for the focus navigation. It is a <string> and it MUST NOT start with the underscore \"_\" character. Error handling: if it does start with an underscore, \"_parent\" navigates to the parent frame, \"_root\" is treated as root, and other values navigate to a frame by that name if it exists. If the specified target frame does not exist, the parameter will be treated as the keyword current, which means to simply use the frame that the element is in. The keyword root indicates that the user agent should target the full window."
+    }
+  }
+}
diff --git a/whatwg/css/css-values.json b/whatwg/css/css-values.json
new file mode 100644
index 000000000000..fa2d093dafb3
--- /dev/null
+++ b/whatwg/css/css-values.json
@@ -0,0 +1,45 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<url>": {
+      "value": "url( <string> <url-modifier>* )"
+    },
+    "<position>": {
+      "value": "[ [ left | center | right ] || [ top | center | bottom ] | [ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ]? | [ [ left | right ] <length-percentage> ] && [ [ top | bottom ] <length-percentage> ] ]"
+    },
+    "<calc()>": {
+      "value": "calc( <calc-sum> )"
+    },
+    "<min()>": {
+      "value": "min( <calc-sum># )"
+    },
+    "<max()>": {
+      "value": "max( <calc-sum># )"
+    },
+    "<clamp()>": {
+      "value": "clamp( <calc-sum>#{3} )"
+    },
+    "<calc-sum>": {
+      "value": "<calc-product> [ [ '+' | '-' ] <calc-product> ]*"
+    },
+    "<calc-product>": {
+      "value": "<calc-value> [ [ '*' | '/' ] <calc-value> ]*"
+    },
+    "<calc-value>": {
+      "value": "<number> | <dimension> | <percentage> | ( <calc-sum> )"
+    },
+    "<length-percentage>": {
+      "value": "[ <length> | <percentage> ]"
+    },
+    "<frequency-percentage>": {
+      "value": "[ <frequency> | <percentage> ]"
+    },
+    "<angle-percentage>": {
+      "value": "[ <angle> | <percentage> ]"
+    },
+    "<time-percentage>": {
+      "value": "[ <time> | <percentage> ]"
+    }
+  }
+}
diff --git a/whatwg/css/css-variables.json b/whatwg/css/css-variables.json
new file mode 100644
index 000000000000..0b19ea46b7ed
--- /dev/null
+++ b/whatwg/css/css-variables.json
@@ -0,0 +1,9 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<var()>": {
+      "value": "var( <custom-property-name> [, <declaration-value> ]? )"
+    }
+  }
+}
diff --git a/whatwg/css/css-will-change.json b/whatwg/css/css-will-change.json
new file mode 100644
index 000000000000..54ac19bd82b4
--- /dev/null
+++ b/whatwg/css/css-will-change.json
@@ -0,0 +1,21 @@
+{
+  "properties": {
+    "will-change": {
+      "name": "will-change",
+      "value": "auto | <animateable-feature>#",
+      "initial": "auto",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "not animatable"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<animateable-feature>": {
+      "value": "scroll-position | contents | <custom-ident>"
+    }
+  }
+}
diff --git a/whatwg/css/css-writing-modes.json b/whatwg/css/css-writing-modes.json
new file mode 100644
index 000000000000..5901f0eaeeb4
--- /dev/null
+++ b/whatwg/css/css-writing-modes.json
@@ -0,0 +1,72 @@
+{
+  "properties": {
+    "direction": {
+      "name": "direction",
+      "value": "ltr | rtl",
+      "initial": "ltr",
+      "appliesTo": "all elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "n/a",
+      "animationType": "not animatable"
+    },
+    "unicode-bidi": {
+      "name": "unicode-bidi",
+      "value": "normal | embed | isolate | bidi-override | isolate-override | plaintext",
+      "initial": "normal",
+      "appliesTo": "all elements, but see prose",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animationType": "not animatable"
+    },
+    "writing-mode": {
+      "name": "writing-mode",
+      "value": "horizontal-tb | vertical-rl | vertical-lr | sideways-rl | sideways-lr",
+      "initial": "horizontal-tb",
+      "appliesTo": "All elements except table row groups, table column groups, table rows, table columns, ruby base container, ruby annotation container",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "n/a",
+      "animationType": "not animatable"
+    },
+    "text-orientation": {
+      "name": "text-orientation",
+      "value": "mixed | upright | sideways",
+      "initial": "mixed",
+      "appliesTo": "all elements except table row groups, rows, column groups, and columns",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "n/a",
+      "animationType": "not animatable"
+    },
+    "glyph-orientation-vertical": {
+      "name": "glyph-orientation-vertical",
+      "value": "auto | 0deg | 90deg | 0 | 90",
+      "initial": "n/a",
+      "appliesTo": "n/a",
+      "inherited": "na/",
+      "percentages": "n/a",
+      "computedValue": "n/a",
+      "canonicalOrder": "n/a",
+      "animatable": "n/a"
+    },
+    "text-combine-upright": {
+      "name": "text-combine-upright",
+      "value": "none | all | [ digits <integer>? ]",
+      "initial": "none",
+      "appliesTo": "non-replaced inline elements",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "specified keyword, plus integer if digits",
+      "canonicalOrder": "n/a",
+      "animationType": "not animatable"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/cssom-view.json b/whatwg/css/cssom-view.json
new file mode 100644
index 000000000000..86baa507ff11
--- /dev/null
+++ b/whatwg/css/cssom-view.json
@@ -0,0 +1,17 @@
+{
+  "properties": {
+    "scroll-behavior": {
+      "name": "scroll-behavior",
+      "value": "auto | smooth",
+      "initial": "auto",
+      "appliesTo": "scrolling boxes",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "specified value",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/fill-stroke.json b/whatwg/css/fill-stroke.json
new file mode 100644
index 000000000000..5a96b1940e23
--- /dev/null
+++ b/whatwg/css/fill-stroke.json
@@ -0,0 +1,352 @@
+{
+  "properties": {
+    "fill-rule": {
+      "name": "fill-rule",
+      "value": "nonzero | evenodd",
+      "initial": "nonzero",
+      "appliesTo": "SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "fill-break": {
+      "name": "fill-break",
+      "value": "bounding-box | slice | clone",
+      "initial": "bounding-box",
+      "appliesTo": "all elements",
+      "inherited": "yes?",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "No"
+    },
+    "fill-color": {
+      "name": "fill-color",
+      "value": "<color>",
+      "initial": "currentcolor",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "the computed color",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as color"
+    },
+    "fill-image": {
+      "name": "fill-image",
+      "value": "<paint>#",
+      "initial": "none",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified, with URLs made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of images"
+    },
+    "fill-origin": {
+      "name": "fill-origin",
+      "value": "match-parent | fill-box | stroke-box | content-box | padding-box | border-box",
+      "initial": "match-parent",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "fill-position": {
+      "name": "fill-position",
+      "value": "<position>#",
+      "initial": "0% 0%",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "A list, each item consisting of: a pair of offsets (horizontal and vertical) from the top left origin each given as a combination of an absolute length and a percentage",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of simple list of length, percentage, or calc"
+    },
+    "fill-size": {
+      "name": "fill-size",
+      "value": "<bg-size>#",
+      "initial": "auto",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified, but with lengths made absolute and omitted auto keywords filled in",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of simple list of length, percentage, or calc"
+    },
+    "fill-repeat": {
+      "name": "fill-repeat",
+      "value": "<repeat-style>#",
+      "initial": "repeat",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "A list, each item consisting of: two keywords, one per dimension",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "fill": {
+      "name": "fill",
+      "value": "<‘background’> with modifications",
+      "initial": "See individual properties",
+      "appliesTo": "See individual properties",
+      "inherited": "See individual properties",
+      "percentages": "N/A",
+      "computedValue": "See individual properties",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "See individual properties"
+    },
+    "fill-opacity": {
+      "name": "fill-opacity",
+      "value": "<‘opacity’>",
+      "initial": "1",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "the specified value converted to a <number>, clamped to the range [0,1]",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as number"
+    },
+    "stroke-width": {
+      "name": "stroke-width",
+      "value": "<length-percentage>#",
+      "initial": "1px",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "relative to the scaled viewport size",
+      "computedValue": "the absolute length, or percentage",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as <length-percentage>"
+    },
+    "stroke-align": {
+      "name": "stroke-align",
+      "value": "center | inset | outset",
+      "initial": "center",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "stroke-linecap": {
+      "name": "stroke-linecap",
+      "value": "butt | round | square",
+      "initial": "butt",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "stroke-linejoin": {
+      "name": "stroke-linejoin",
+      "value": "[ crop | arcs | miter ] || [ bevel | round | stupid ]",
+      "initial": "miter",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "stroke-miterlimit": {
+      "name": "stroke-miterlimit",
+      "value": "<number>",
+      "initial": "4",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "a number",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "stroke-break": {
+      "name": "stroke-break",
+      "value": "bounding-box | slice | clone",
+      "initial": "bounding-box",
+      "appliesTo": "all elements",
+      "inherited": "?",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "No"
+    },
+    "stroke-dasharray": {
+      "name": "stroke-dasharray",
+      "value": "none | <length-percentage>+#",
+      "initial": "none",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "relative to the scaled viewport size",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeated list of length, percentage or calc"
+    },
+    "stroke-dashoffset": {
+      "name": "stroke-dashoffset",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "relative to the scaled viewport size",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeated list of integers"
+    },
+    "stroke-dash-corner": {
+      "name": "stroke-dash-corner",
+      "value": "none | <length>",
+      "initial": "none",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "specified value, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "yes, if <length>"
+    },
+    "stroke-dash-justify": {
+      "name": "stroke-dash-justify",
+      "value": "none | [ stretch | compress ] || [ dashes || gaps ]",
+      "initial": "none",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "specified value, with lengths made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "stroke-color": {
+      "name": "stroke-color",
+      "value": "<color>#",
+      "initial": "transparent",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "the computed color",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as color"
+    },
+    "stroke-image": {
+      "name": "stroke-image",
+      "value": "<paint>#",
+      "initial": "none",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "as specified, with URLs made absolute",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of images"
+    },
+    "stroke-origin": {
+      "name": "stroke-origin",
+      "value": "match-parent | fill-box | stroke-box | content-box | padding-box | border-box",
+      "initial": "match-parent",
+      "appliesTo": "all elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "stroke-position": {
+      "name": "stroke-position",
+      "value": "<position>#",
+      "initial": "0% 0%",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "A list, each item consisting of: a pair of offsets (horizontal and vertical) from the top left origin each given as a combination of an absolute length and a percentage",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of simple list of length, percentage, or calc"
+    },
+    "stroke-size": {
+      "name": "stroke-size",
+      "value": "<bg-size>#",
+      "initial": "auto",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "as specified, but with lengths made absolute and omitted auto keywords filled in",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as repeatable list of simple list of length, percentage, or calc"
+    },
+    "stroke-repeat": {
+      "name": "stroke-repeat",
+      "value": "<repeat-style>#",
+      "initial": "repeat",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "n/a",
+      "computedValue": "A list, each item consisting of: two keywords, one per dimension",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "no"
+    },
+    "stroke": {
+      "name": "stroke",
+      "value": "<‘background’> with modifications",
+      "initial": "See individual properties",
+      "appliesTo": "See individual properties",
+      "inherited": "See individual properties",
+      "percentages": "N/A",
+      "computedValue": "See individual properties",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "See individual properties"
+    },
+    "stroke-opacity": {
+      "name": "stroke-opacity",
+      "value": "<‘opacity’>",
+      "initial": "1",
+      "appliesTo": "inline boxes and SVG shapes",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "computedValue": "the specified value converted to a <number>, clamped to the range [0,1]",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as number"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<paint>": {
+      "value": "none | <image> | <svg-paint>"
+    },
+    "<svg-paint>": {
+      "value": "child | child( <integer> )"
+    },
+    "<child()>": {
+      "value": "child(<integer>)"
+    }
+  }
+}
diff --git a/whatwg/css/filter-effects.json b/whatwg/css/filter-effects.json
new file mode 100644
index 000000000000..e5d1a8e4b9f6
--- /dev/null
+++ b/whatwg/css/filter-effects.json
@@ -0,0 +1,18 @@
+{
+  "properties": {
+    "backdrop-filter": {
+      "name": "backdrop-filter",
+      "value": "none | <filter-function-list>",
+      "initial": "none",
+      "appliesTo": "All elements. In SVG, it applies to container elements without the defs element and all graphics elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "yes"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/mediaqueries.json b/whatwg/css/mediaqueries.json
new file mode 100644
index 000000000000..a241e3bdb548
--- /dev/null
+++ b/whatwg/css/mediaqueries.json
@@ -0,0 +1,54 @@
+{
+  "properties": {},
+  "descriptors": {
+    "light-level": {
+      "name": "light-level",
+      "for": "@media",
+      "value": "dim | normal | washed",
+      "type": "discrete"
+    },
+    "environment-blending": {
+      "name": "environment-blending",
+      "for": "@media",
+      "value": "opaque | additive | subtractive",
+      "type": "discrete"
+    },
+    "scripting": {
+      "name": "scripting",
+      "for": "@media",
+      "value": "none | initial-only | enabled",
+      "type": "discrete"
+    },
+    "inverted-colors": {
+      "name": "inverted-colors",
+      "for": "@media",
+      "value": "none | inverted",
+      "type": "discrete"
+    },
+    "prefers-reduced-motion": {
+      "name": "prefers-reduced-motion",
+      "for": "@media",
+      "value": "no-preference | reduce",
+      "type": "discrete"
+    },
+    "prefers-reduced-transparency": {
+      "name": "prefers-reduced-transparency",
+      "for": "@media",
+      "value": "no-preference | reduce",
+      "type": "discrete"
+    },
+    "prefers-contrast": {
+      "name": "prefers-contrast",
+      "for": "@media",
+      "value": "no-preference | high | low",
+      "type": "discrete"
+    },
+    "prefers-color-scheme": {
+      "name": "prefers-color-scheme",
+      "for": "@media",
+      "value": "no-preference | light | dark",
+      "type": "discrete"
+    }
+  },
+  "valuespaces": {}
+}
diff --git a/whatwg/css/motion.json b/whatwg/css/motion.json
new file mode 100644
index 000000000000..be152257a5e8
--- /dev/null
+++ b/whatwg/css/motion.json
@@ -0,0 +1,88 @@
+{
+  "properties": {
+    "offset-path": {
+      "name": "offset-path",
+      "value": "none | ray() | path() | <url> | [ <basic-shape> || <geometry-box> ]",
+      "initial": "none",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as <angle>, <basic-shape> or path()"
+    },
+    "offset-distance": {
+      "name": "offset-distance",
+      "value": "<length-percentage>",
+      "initial": "0",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "refer to the total path length",
+      "computedValue": "For <length> the absolute value, otherwise a percentage.",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "yes"
+    },
+    "offset-position": {
+      "name": "offset-position",
+      "value": "auto | <position>",
+      "initial": "auto",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "Refer to the size of containing block",
+      "computedValue": "For <length> the absolute value, otherwise a percentage.",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as position"
+    },
+    "offset-anchor": {
+      "name": "offset-anchor",
+      "value": "auto | <position>",
+      "initial": "auto",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "Relative to the width and the height of a box",
+      "computedValue": "For <length> the absolute value, otherwise a percentage.",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "as <position>"
+    },
+    "offset-rotate": {
+      "name": "offset-rotate",
+      "value": "[ auto | reverse ] || <angle>",
+      "initial": "auto",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "yes"
+    },
+    "offset": {
+      "name": "offset",
+      "value": "[ offset-position? [ offset-path [ offset-distance || offset-rotate ]? ]? ]! [ / offset-anchor ]?",
+      "initial": "see individual properties",
+      "appliesTo": "transformable elements",
+      "inherited": "no",
+      "percentages": "see individual properties",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "media": "visual",
+      "animatable": "see individual properties"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<ray()>": {
+      "value": "ray( [ <angle> && <size> && contain? ] )"
+    },
+    "<path()>": {
+      "value": "path(<string>)"
+    },
+    "<size>": {
+      "prose": "Decides the path length used when offset-distance is expressed as a percentage, using the distance to the containing box. For <size> values other than sides, the path length is independent of <angle>. It is defined as <size> = [ closest-side | closest-corner | farthest-side | farthest-corner | sides ] closest-side The perpendicular distance is measured between the initial position and the closest side of the box from it. closest-corner The distance is measured between the initial position and the closest corner of the box from it. farthest-side The perpendicular distance is measured between the initial position and the farthest side of the box from it. farthest-corner The distance is measured between the initial position and the farthest corner of the box from it. sides The distance is measured between the initial position and the intersection of the ray with the box. If the initial position is not within the box, the distance is 0. Note: When the initial position is on one of the edges of the containing block, the closest side takes the edge that the initial position is on, and thus the path length used for percentage offset-distance values is 0. Note: When closest-side or farthest-side are used, and the initial position is outside the box, the sides are considered to extend indefinitely."
+    }
+  }
+}
diff --git a/whatwg/css/overscroll-behavior.json b/whatwg/css/overscroll-behavior.json
new file mode 100644
index 000000000000..3cd6381d5bef
--- /dev/null
+++ b/whatwg/css/overscroll-behavior.json
@@ -0,0 +1,42 @@
+{
+  "properties": {
+    "overscroll-behavior-x": {
+      "name": "overscroll-behavior-x",
+      "value": "contain | none | auto",
+      "initial": "auto",
+      "appliesTo": "scroll container elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "overscroll-behavior-y": {
+      "name": "overscroll-behavior-y",
+      "value": "contain | none | auto",
+      "initial": "auto",
+      "appliesTo": "scroll container elements",
+      "inherited": "no",
+      "percentages": "N/A",
+      "media": "visual",
+      "computedValue": "as specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    },
+    "overscroll-behavior": {
+      "name": "overscroll-behavior",
+      "value": "[ contain | none | auto ]{1,2}",
+      "initial": "auto auto",
+      "appliesTo": "scroll container elements",
+      "inherited": "no",
+      "percentages": "n/a",
+      "media": "visual",
+      "computedValue": "see individual properties",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {}
+}
diff --git a/whatwg/css/scroll-animations.json b/whatwg/css/scroll-animations.json
new file mode 100644
index 000000000000..5284f5b3ec00
--- /dev/null
+++ b/whatwg/css/scroll-animations.json
@@ -0,0 +1,28 @@
+{
+  "properties": {
+    "animation-timeline": {
+      "name": "animation-timeline",
+      "value": "<single-animation-timeline>#",
+      "initial": "auto",
+      "appliesTo": "all elements, ::before and ::after pseudo-elements",
+      "inherited": "none",
+      "percentages": "N/A",
+      "media": "interactive",
+      "computedValue": "As specified",
+      "canonicalOrder": "per grammar",
+      "animatable": "no"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<single-animation-timeline>": {
+      "value": "auto | scroll([element(<id-selector>)[, <scroll-direction>[, <scroll-offset>[, <scroll-offset>[, <time>[, <single-animation-fill-mode>]]]]]])"
+    },
+    "<scroll-direction>": {
+      "value": "auto | block | inline | horizontal | vertical"
+    },
+    "<scroll-offset>": {
+      "value": "<length> | <percentage> | auto"
+    }
+  }
+}
diff --git a/whatwg/css/selectors-nonelement.json b/whatwg/css/selectors-nonelement.json
new file mode 100644
index 000000000000..8a4ce2c08d88
--- /dev/null
+++ b/whatwg/css/selectors-nonelement.json
@@ -0,0 +1,18 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<::attr()>": {
+      "value": "::attr( <namespace-attr>? )"
+    },
+    "<namespace-attr>": {
+      "value": "[ <na-prefix>? '|' ]? <na-name>"
+    },
+    "<na-prefix>": {
+      "value": "<ident> | '*'"
+    },
+    "<na-name>": {
+      "value": "<ident> | '*'"
+    }
+  }
+}
diff --git a/whatwg/css/selectors.json b/whatwg/css/selectors.json
new file mode 100644
index 000000000000..972d13708c68
--- /dev/null
+++ b/whatwg/css/selectors.json
@@ -0,0 +1,69 @@
+{
+  "properties": {},
+  "descriptors": {},
+  "valuespaces": {
+    "<selector-list>": {
+      "value": "<complex-selector-list>"
+    },
+    "<complex-selector-list>": {
+      "value": "<complex-selector>#"
+    },
+    "<compound-selector-list>": {
+      "value": "<compound-selector>#"
+    },
+    "<simple-selector-list>": {
+      "value": "<simple-selector>#"
+    },
+    "<relative-selector-list>": {
+      "value": "<relative-selector>#"
+    },
+    "<complex-selector>": {
+      "value": "<compound-selector> [ <combinator>? <compound-selector> ]*"
+    },
+    "<relative-selector>": {
+      "value": "<combinator>? <complex-selector>"
+    },
+    "<compound-selector>": {
+      "value": "[ <type-selector>? <subclass-selector>* [ <pseudo-element-selector> <pseudo-class-selector>* ]* ]!"
+    },
+    "<simple-selector>": {
+      "value": "<type-selector> | <subclass-selector>"
+    },
+    "<combinator>": {
+      "value": "'>' | '+' | '~' | [ '||' ]"
+    },
+    "<type-selector>": {
+      "value": "<wq-name> | <ns-prefix>? '*'"
+    },
+    "<ns-prefix>": {
+      "value": "[ <ident-token> | '*' ]? '|'"
+    },
+    "<wq-name>": {
+      "value": "<ns-prefix>? <ident-token>"
+    },
+    "<subclass-selector>": {
+      "value": "<id-selector> | <class-selector> | <attribute-selector> | <pseudo-class-selector>"
+    },
+    "<id-selector>": {
+      "value": "<hash-token>"
+    },
+    "<class-selector>": {
+      "value": "'.' <ident-token>"
+    },
+    "<attribute-selector>": {
+      "value": "'[' <wq-name> ']' | '[' <wq-name> <attr-matcher> [ <string-token> | <ident-token> ] <attr-modifier>? ']'"
+    },
+    "<attr-matcher>": {
+      "value": "[ '~' | '|' | '^' | '$' | '*' ]? '='"
+    },
+    "<attr-modifier>": {
+      "value": "i"
+    },
+    "<pseudo-class-selector>": {
+      "value": "':' <ident-token> | ':' <function-token> <any-value> ')'"
+    },
+    "<pseudo-element-selector>": {
+      "value": "':' <pseudo-class-selector>"
+    }
+  }
+}
diff --git a/whatwg/css/svg-markers.json b/whatwg/css/svg-markers.json
new file mode 100644
index 000000000000..9817fd021efb
--- /dev/null
+++ b/whatwg/css/svg-markers.json
@@ -0,0 +1,113 @@
+{
+  "properties": {
+    "marker-start": {
+      "name": "marker-start",
+      "value": "none | <marker-ref>",
+      "initial": "none",
+      "appliesTo": "shape elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker-mid": {
+      "name": "marker-mid",
+      "value": "none | <marker-ref>",
+      "initial": "none",
+      "appliesTo": "shape elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker-end": {
+      "name": "marker-end",
+      "value": "none | <marker-ref>",
+      "initial": "none",
+      "appliesTo": "shape elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker-segment": {
+      "name": "marker-segment",
+      "value": "none | <marker-ref>",
+      "initial": "none",
+      "appliesTo": "shape elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker-pattern": {
+      "name": "marker-pattern",
+      "value": "<marker-gap>? <marker-ref-group> [ <marker-gap> <marker-ref-group> ]* <marker-gap>?",
+      "initial": "none",
+      "appliesTo": "shape elements",
+      "inherited": "yes",
+      "percentages": "refer to the length of the path",
+      "media": "visual",
+      "computed value": "as specified, but with <url> values (that are part of a <marker-ref>) made absolute",
+      "animatable": "yes"
+    },
+    "marker": {
+      "name": "marker",
+      "value": "[ none | <marker-ref> ]{1,4} [ / <‘marker-pattern’> ]? | <marker-ref>{0,4} [ <length> | <percentage> | <number> ] [ <length> | <percentage> | <number> | <marker-ref> ]*",
+      "initial": "not defined for shorthand properties",
+      "appliesTo": "shape elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "see individual properties",
+      "animatable": "yes"
+    },
+    "marker-knockout-left": {
+      "name": "marker-knockout-left",
+      "value": "<knockout-offset> | <knockout-shape> [ at <knockout-offset> ]?",
+      "initial": "0",
+      "appliesTo": "‘marker’",
+      "inherited": "no",
+      "percentages": "see prose",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "marker-knockout-right": {
+      "name": "marker-knockout-right",
+      "value": "<knockout-offset> | <knockout-shape> [ at <knockout-offset> ]?",
+      "initial": "0",
+      "appliesTo": "‘marker’",
+      "inherited": "no",
+      "percentages": "see prose",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<marker-ref>": {
+      "value": "<url> | child | <child-selector>"
+    },
+    "<child-selector>": {
+      "value": "select(compound selector#)"
+    },
+    "<marker-gap>": {
+      "value": "<length> | <percentage> | <number>"
+    },
+    "<marker-ref-group>": {
+      "value": "none | <marker-ref>+"
+    },
+    "<knockout-offset>": {
+      "value": "[ <length> | <percentage> | <number> ]"
+    },
+    "<knockout-shape>": {
+      "value": "[ <length> | <percentage> | <number> ] inverted? circle | [ <length> | <percentage> | <number> ]{2} inverted? ellipse | [ <length> | <percentage> | <number> ]{1,2} inverted? [ rectangle | triangle ]"
+    }
+  }
+}
diff --git a/whatwg/css/svg-strokes.json b/whatwg/css/svg-strokes.json
new file mode 100644
index 000000000000..d7af8c5fa8c1
--- /dev/null
+++ b/whatwg/css/svg-strokes.json
@@ -0,0 +1,131 @@
+{
+  "properties": {
+    "stroke": {
+      "name": "stroke",
+      "value": "<paint>",
+      "initial": "none",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but with <color> values computed and <url> values made absolute",
+      "animatable": "yes"
+    },
+    "stroke-alignment": {
+      "name": "stroke-alignment",
+      "value": "center | inner | outer",
+      "initial": "center",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "stroke-opacity": {
+      "name": "stroke-opacity",
+      "value": "<number>",
+      "initial": "1",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified, but clamped to the range [0, 1]",
+      "animatable": "yes"
+    },
+    "stroke-width": {
+      "name": "stroke-width",
+      "value": "<percentage> | <length>",
+      "initial": "1",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "refer to the size of the current viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "stroke-linecap": {
+      "name": "stroke-linecap",
+      "value": "butt | round | square",
+      "initial": "butt",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "stroke-linejoin": {
+      "name": "stroke-linejoin",
+      "value": "miter | miter-clip | round | bevel | arcs",
+      "initial": "miter",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "stroke-miterlimit": {
+      "name": "stroke-miterlimit",
+      "value": "<number>",
+      "initial": "4",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    },
+    "stroke-dasharray": {
+      "name": "stroke-dasharray",
+      "value": "none | <dasharray>",
+      "initial": "none",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "refer to the size of the current viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute lengths or percentages for <dasharray>, or keyword specified",
+      "animatable": "yes (non-additive)"
+    },
+    "stroke-dashoffset": {
+      "name": "stroke-dashoffset",
+      "value": "<length> | <percentage>",
+      "initial": "0",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "refer to the size of the current viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute length or percentage",
+      "animatable": "yes"
+    },
+    "stroke-dashcorner": {
+      "name": "stroke-dashcorner",
+      "value": "none | <length>",
+      "initial": "none",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "refer to the size of the current viewport (see Units)",
+      "media": "visual",
+      "computed value": "absolute length or keyword specified",
+      "animatable": "yes"
+    },
+    "stroke-dashadjust": {
+      "name": "stroke-dashadjust",
+      "value": "none | [stretch | compress] [dashes | gaps]?",
+      "initial": "none",
+      "appliesTo": "shapes and text content elements",
+      "inherited": "yes",
+      "percentages": "N/A",
+      "media": "visual",
+      "computed value": "as specified",
+      "animatable": "yes"
+    }
+  },
+  "descriptors": {},
+  "valuespaces": {
+    "<dasharray>": {
+      "value": "[ <length> | <percentage> | <number> ]#*"
+    }
+  }
+}