A colour is a either a colour name or a numerical RGB specification. The Style Sheet specification (and style sheets as implemented by Microsoft in the Internet Explorer) supports all of the Netscape colour names.

The following all specify a red colour

EM { color: #F00 }	#RGB
EM { color: #FF0000 }	#RRGGBB
EM { color: rgb(255,0,0)	integer range 0 - 255
EM { color: rgb(100%, 0%, 0%)	float range 0.0% - 100.0%

Note that a three-digit RGB notation (#RGB) is converted into six-digit form (#RRGGBB) by replicating digits, not by adding zeros. For example, #fb0 expands to #ffbb00.

Values outside the numerical ranges will be rounded off. The three rules below are therefore equivalent:

EM { color: rgb(255,0,0)	integer range 0 - 255
EM { color: rgb(300,0,0)	rounded off to 255
EM { color: rgb(110%, 0%, 0%)	rounded off to 100%

© 1995-1998, Stephen Le Hunte