The hex color #21bf3e is a light color. The web-safe version is Hex
#33CC33. A complementary color is
#DE40C1. The grayscale version is
#5F5F5F. A 20% lighter version of the original color is
#54F271, and Hex
#008C0B is the 20% darker color. If the color is saturated by 10%, you get
#1BC93B. If the color is desaturated by 10%, the color
#27B541 is obtained.