HTML Colour Names

" If you want your pages to validate with an HTML or a CSS validator, W3C has listed 16 color names that you can use: aqua, black, blue, fuchsia, gray, green, lime, maroon, navy, olive, purple, red, silver, teal, white, and yellow. If you want to use other colors, you must specify their RGB or HEX value."

http://www.w3schools.com/html/html_colornames.asp