Or color – the American spelling is used on the web. The English version is used in novels.
We have a system for specifying a colour with 256 stages for each primary.
RGBA = Red Green Blue Alpha. Alpha is the opacity level, and defaults to 1 (100% – i.e. no transparency).
Technical
Hex colours are expressed as a triplet of hex numbers (i.e. hex numerals from 0 to 15 are reprented as 0, 1, 2,3, 4, 5, 6,7, 8, 9, A, B, C, D, E. 255 is represented as 0xFF or just FF
Each colour can be represented with a leading #RRGGBB series, or as an rgb or rgba function.
Examples
#000000 = no colour = black
#00ff00 = 100% green
#ffff00 = 100% yellow
rgb(23,34,45) = #233445
rgb(255,0,0) = red = #ff0000
Useful Link
For a useful colour tool to mix your own pallet try this:
https://www.hexcolortool.com/#8dbfb6