There are several ways to insert colors into web pages. Text or background color is defined with an identifier or with a list of RGB components.
Identifier - You can use the english name of colors: red, blue, gray, green, etc. You can find the full list in left table below.
RGB - RGB format use, to define colors, three integers numbers thru 0 and 255, with a range of linear values. White become 255,255,255. Black 0,0,0. Red 255,0,0 and chromatic differences thru values combination. In HTML numeric values of colors are defined with "exadecimal trio", or conversion of three numbers RGB into 2 values exadecimals.
Use left table to choose colors based on HTML standard name, right table to see HEX numbers (exadecimals) of same colors (with mouseover).
Chosed a color, find it into list ordered by Name or by Value to see it as background to colored text.