Hex Color Code
A 6-character hexadecimal representation of a color (e.g. #FF5733). Each pair of characters encodes the red, green, and blue components from 00 to FF (0-255).
Definition
A hex (hexadecimal) color code is the most common way to specify colors in HTML and CSS. It's a six-character string starting with #, where the first two characters represent red (00-FF), the next two green, and the last two blue. So #FF5733 is rgb(255, 87, 51) — full red, mid-green, low-blue.
Formula
Each pair = decimal value 0-255 in base 16. #RRGGBB. Three-digit shortcut #RGB expands to #RRGGBB (so #F53 = #FF5533).
Example
#000000 is pure black. #FFFFFF is pure white. #FF0000 is pure red. #E0B0FF is Mauve.