Added color css variables.

src/styl/colors.styl

@@ -25,3 +25,30 @@ $brown-dark ?= darken($brown, $darker);
 $brown-light ?= lighten($brown, $lighter);
 $orange-dark ?= darken($orange, $darker);
 $orange-light ?= lighten($orange, $lighter);
+
+:root {
+    --color-white: $white;
+    --color-black: $black;
+    --color-gray: $gray;
+    --color-red: $red;
+    --color-blue: $blue;
+    --color-yellow: $yellow;
+    --color-green: $green;
+    --color-brown: $brown;
+    --color-orange: $orange;
+
+    --color-gray-dark: $gray-dark;
+    --color-gray-light: $gray-light;
+    --color-red-dark: $red-dark;
+    --color-red-light: $red-light;
+    --color-blue-dark: $blue-dark;
+    --color-blue-light: $blue-light;
+    --color-yellow-dark: $yellow-dark;
+    --color-yellow-light: $yellow-light;
+    --color-green-dark: $green-dark;
+    --color-green-light: $green-light;
+    --color-brown-dark: $brown-dark;
+    --color-brown-light: $brown-light;
+    --color-orange-dark: $orange-dark;
+    --color-orange-light: $orange-light;
+}