Color Shorthand

Once you've started using CSS layouts for your Web designs, you may observe something odd about the way the colors are distinct. Rather than the standard 6-character long code following the pound sign (#cc99ff), instead you see just three characters (#c9f). This is called color shorthand and it takes benefit of the fact that the browser-safe Web palette uses triplets that are always doubled. In other words, each color triplet is made of 3 pairs of characters 0-f (base 16), and with browser-safe colors they are doubled. So, to write color shorthand, you simply take away the duplicate character.

White is written #fff in shorthand
Black is written #000
Red is #f00
Green is #0f0
Blue is #00f
and so on...