Wikipedia has the following description on HEX color codes: "A HEX triplet is a six-digit, three-byte hexadecimal number used in HTML, CSS, SVG, and other computing applications to represent colors. The bytes represent the Red, Green and Blue components of the color. One byte represents a number in the range 00 to FF (in hexadecimal notation), or 0 to 255 in decimal notation. This represents the least (0) to the most (255) intensity of each of the color components." You can find more information about HEX codes and web colors on Wikipedia.