HEX, RGB and HSL
HEX writes the red, green and blue channels as three two-digit hexadecimal numbers (#FF5733). RGB gives the same channels as numbers from 0 to 255 (255, 87, 51). HSL describes the color as hue (0–360°), saturation and lightness (%), which is easier for making lighter or darker shades.
How to convert HEX to RGB
Split the six digits into pairs and convert each pair from base 16 to base 10: FF = 255, 57 = 87, 33 = 51. Three-digit shorthand codes double each digit, so #F53 is #FF5533.