With the popular browsers and according to the Cascading Style Sheets (CSS) standard, you may prescribe the display color for various elements in your documents. You do so by specifying a color value or a standard name. The user may override these color specifications through their browser preferences.
In all cases, you may set the color value for an HTML element, such as <body> text, <table> background, and so on, as a six-digit hexadecimal number that represents the red, green, and blue (RGB) components of the color. The first two digits correspond to the red component of the color, the next two are the green component, and the last two are the blue component. A value of 00 corresponds to a component being completely off; the hexadecimal value of FF (decimal 255) corresponds to the component being completely on. Thus, bright red is FF0000, bright green is 00FF00, and bright blue is 0000FF. Other primary colors are mixtures of the components, such as yellow (FFFF00), magenta (FF00FF), and cyan (00FFFF). White (FFFFFF) and black (000000) are also easy to figure out.
You use these values in a tag by replacing the color with the RGB triple, preceded by a pound sign (#). Thus, to make all visited links display as magenta, use this body tag:
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