Elements of Style - HTML Manual of Style - page 138

in the X11 window standard, including brown , pink , tan , cyan , magenta , gold ,
and the ever-popular chartreuse . For example:

p.crazy { color: chartreuse; }

In general, authors are advised to use colors from the set of 17 names to
ensure that their colors are displayed correctly on the widest variety of devices.
Color values can be precisely deined by giving a triplet of values for the
component colors red, green, and blue (RGB). Each component color is
represented by a number from 0 to 255, or by a percentage from 0 percent
to 100 percent, signifying how much of that color to contribute—from none
to the display's maximum brightness. If all the component colors have the
same value, the resulting color will be along the gray scale. Here are a couple
examples:

.nav li a { color: rgb(0,0,51); } /* very dark blue */
address { color: rgb(255,255,255); } /* white */

Colors can also be speciied using hexadecimal (base 16) notation. he
long-format hexadecimal notation is a hash mark (#) followed by six hexa-
decimal digits. A hexadecimal digit is one of the digits from 0 to 9 or a letter
from a to f, standing in for the numbers 10 through 15. he digits are grouped
into pairs. he irst two digits represent the red component, the second two
represent the green component, and the last two represent blue. Table 3.2
shows the 17 CSS2.1 colors and their corresponding decimal, percentage, and
hexadecimal values.

Table 3.2: CSS2.1 colors

Color Name RGB Decimal RGB Percentage Hexadecimal

black rgb(0,0,0) rgb(0%,0%,0%) #000000

white rgb(255,255,255) rgb(100%,100%,100%) #ffffff

red rgb(255,0,0) rgb(100%,0%,0%) #ff0000

yellow rgb(255,255,0) rgb(100%,100%,0%) #ffff00

green rgb(0,128,0) rgb(0%,50%,0%) #008000

aqua rgb(0,255,255) rgb(0%,100%,100%) #00ffff

continues