Color
CSS 2.1中共定義17個顏色關鍵字(color keywords)
aqua, #00FFFF
black, #000000
blue, #0000FF
fuchsia, #FF00FF
gray, #808080
green, #008000
lime, #00FF00
maroon, #800000
navy, #000080
olive, #808000
orange, #FFA500
purple, #800080
red, #FF0000
silver, #C0C0C0
teal, #008080
white, #FFFFFF
yellow, #FFFF00
color (CSS data type)
Syntax and basic data types
CSS Color Module Level 3