The hex color #213ccc is a dark color. The web-safe version is Hex
#3333CC. A complementary color is
#DEC333. The grayscale version is
#636363. A 20% lighter version of the original color is
#546FFF, and Hex
#000999 is the 20% darker color. If the color is saturated by 10%, you get
#1A38D7. If the color is desaturated by 10%, the color
#2840C2 is obtained.