Colour to tint with. It takes colours in the following formats:
#RGB — shorthand hexadecimal.
#RGBA — shorthand hexadecimal with alpha.
#RRGGBB — hexadecimal.
#RRGGBBAA — hexadecimal with alpha.
rgb(R,G,B) — red, green, blue between 0 and 100 (no spaces).
rgba(R,G,B,A) — red, green, blue between 0 and 100, alpha between 0 and 1 (no spaces).