diff --git a/packages/svelte-vscode/syntaxes/svelte.tmLanguage.src.yaml b/packages/svelte-vscode/syntaxes/svelte.tmLanguage.src.yaml
index 5a7ebc4f3..30323f6d4 100644
--- a/packages/svelte-vscode/syntaxes/svelte.tmLanguage.src.yaml
+++ b/packages/svelte-vscode/syntaxes/svelte.tmLanguage.src.yaml
@@ -339,17 +339,26 @@ repository:
   # Matches attribute keyvalues. (and boolean attributes as well)
   # e.g. `class="my-class"`
   attributes-keyvalue:
-    begin: ([_$[:alpha:]][_\-$[:alnum:]]*)
-    beginCaptures: { 1: { name: entity.other.attribute-name.svelte } }
+    begin: ((?:--)?[_$[:alpha:]][_\-$[:alnum:]]*)
+    beginCaptures:
+      0:
+        patterns:
+        # Matches if the key is a `--css-variable` attribute.
+        - match: --.*
+          name: support.type.property-name.svelte
+        # Matches everything else.
+        - match: .*
+          name: entity.other.attribute-name.svelte
     end: (?=\s*+[^=\s])
     name: 'meta.attribute.$1.svelte'
-    patterns: [ include: '#attributes-value' ]
+    patterns:
+    - begin: '='
+      beginCaptures: { 0: { name: punctuation.separator.key-value.svelte } }
+      end: (?<=[^\s=])(?!\s*=)|(?=/?>)
+      patterns: [include: '#attributes-value']
 
-  # The value part of attribute keyvalues. e.g. `="my-class"` in `class="my-class"`
+  # The value part of attribute keyvalues. e.g. `"my-class"` in `class="my-class"`
   attributes-value:
-    begin: '='
-    beginCaptures: { 0: { name: punctuation.separator.key-value.svelte } }
-    end: (?<=[^\s=])(?!\s*=)|(?=/?>)
     patterns:
     # No quotes - just an interpolation expression.
     - include: '#interpolation'
@@ -365,7 +374,7 @@ repository:
     - begin: (['"])
       end: \1
       beginCaptures: { 0: { name: punctuation.definition.string.begin.svelte } }
-      endCaptures: { 0: { name: punctuation.definition.string.end.svelte } }
+      endCaptures:   { 0: { name: punctuation.definition.string.end.svelte } }
       name: string.quoted.svelte
       patterns: [ include: '#interpolation' ]
 
@@ -419,7 +428,10 @@ repository:
     end: (?=\s*+[^=\s])
     name: meta.directive.$1.svelte
     patterns:
-    - include: '#attributes-value'
+    - begin: '='
+      beginCaptures: { 0: { name: punctuation.separator.key-value.svelte } }
+      end: (?<=[^\s=])(?!\s*=)|(?=/?>)
+      patterns: [include: '#attributes-value']
 
   # ------
   #  TAGS