The hex color #21216c is a dark color. The web-safe version is Hex
#333366. A complementary color is
#DEDE93. The grayscale version is
#3A3A3A. A 20% lighter version of the original color is
#54549F, and Hex
#000039 is the 20% darker color. If the color is saturated by 10%, you get
#1F1F71. If the color is desaturated by 10%, the color
#242467 is obtained.