Add dark Bulma example

docs/bulma-dark.scss

@@ -0,0 +1,35 @@
+@import "../sass/utilities/initial-variables.sass";
+
+// General colors
+
+$scheme-main: $black;
+$scheme-main-bis: $black-bis;
+$scheme-main-ter: $black-ter;
+$scheme-invert: $white;
+$scheme-invert-bis: $white-bis;
+$scheme-invert-ter: $white-ter;
+
+$background: $black-ter;
+
+$border: $grey-darker;
+$border-hover: $grey-dark;
+$border-light: $grey-darker;
+$border-light-hover: $grey-dark;
+
+// Text colors
+
+$text: $grey-light;
+$text-invert: $grey-darker;
+$text-light: $grey;
+$text-strong: $white;
+
+// Link colors
+
+$link-hover: $white;
+$link-hover-border: $grey-dark;
+
+$link-focus: $white;
+$link-focus-border: $blue;
+
+$link-active: $white;
+$link-active-border: $grey-light;