Hexadecimal Colours in CSS

A hexadecimal color is specified with: #RRGGBB, where the RR (red), GG (green) and BB (blue) hexadecimal integers specify the components of the color, from 0 to 255, that is 16 x 16.

For example, #ff0000 is displayed as red, because red is set to its highest value (ff) and the others are set to the lowest value (00).

To display black, set all values to 00, like this: #000000. To display white, set all values to ff, like this: #ffffff.

Three-Digit HEX Value

Sometimes you will see a 3-digit hex code in the CSS source. The 3-digit hex code is a shorthand for some 6-digit hex codes. The 3-digit hex code has the following form:

#rgb

Where r, g, and b represent the red, green, and blue components with values between 0 and f.

The 3-digit hex code can only be used when both the values (RR, GG, and BB) are the same for each component. So, if we have #ff00cc, it can be written like this: #f0c