Adding some doc

Author: louismaximepiton

site/content/docs/5.3/utilities/colors.md

@@ -99,6 +99,8 @@ Most `color` utilities are generated by our theme colors, reassigned from our ge
 
 {{< scss-docs name="theme-color-variables" file="scss/_variables.scss" >}}
 
+{{< scss-docs name="theme-color-dark-variables" file="scss/_variables-dark.scss" >}}
+
 Grayscale colors are also available, but only a subset are used to generate any utilities.
 
 {{< scss-docs name="gray-color-variables" file="scss/_variables.scss" >}}