Colors are specified using RGB values or color names.
E.g the color red can be specified either as #FF0000 or as red.
Valid colors names are:
aliceblue, antiquewhite, aquamarine, azure, beige, bisque, black, blanchedalmond, blue, blueviolet, brown, burlywood, cadetblue, chartreuse, chocolate, coral, cornflowerblue, cornsilk, cyan, darkgoldenrod, darkgreen, darkkhaki, darkolivegreen, darkorange, darkorchid, darksalmon, darkseagreen, darkslateblue, darkslategray, darkslategrey, darkturquoise, darkviolet, deeppink, deepskyblue, dimgray, dimgrey, dodgerblue, firebrick, floralwhite, forestgreen, green, gainsboro, ghostwhite, gold, goldenrod, gray, honeydew, hotpink, indianred, ivory, khaki, lavender, lavenderblush, lawngreen, lemonchiffon, lightblue, lightcoral, lightcyan, lightgoldenrod, lightgoldenrodyellow, lightgray, lightgrey, lightpink, lightsalmon, lightseagreen, lightskyblue, lightslateblue, lightslategray, lightslategrey, lightsteelblue, lightyellow, limegreen, linen, magenta, maroon, mediumaquamarine, mediumblue, mediumorchid, mediumpurple, mediumseagreen, mediumslateblue, mediumspringgreen, mediumturquoise, mediumvioletred, midnightblue, mintcream, mistyrose, moccasin, navajowhite, navy, navyblue, oldlace, olivedrab, orange, orangered, orchid, palegoldenrod, palegreen, paleturquoise, palevioletred, papayawhip, peachpuff, peru, pink, plum, powderblue, purple, red, rosybrown, royalblue, saddlebrown, salmon, sandybrown, seagreen, seashell, sienna, skyblue, slateblue, slategray, slategrey, snow, springgreen, steelblue, tan, thistle, tomato, turquoise, violet, violetred, wheat, white, whitesmoke, yellow and yellowgreen
That should be enough ;-)