RGB is an abbreviation for "Red Green Blue". RGB is a color model used on displays where red, green, and blue light are combined to make millions of colors.
RGB is how colors combine on screens because they are viewed directly, and not reflected off anything - like colors in traditional color theory which is based on reflective colors usually on paper.
CSS allows you to use RGB codes to define your website colors. To define a color in RGB with CSS, write:
The numbers go from 0 to 255, and they are listed in orderred, green, blue.