The hex color #21d53c is a light color. The web-safe version is Hex
#33CC33. A complementary color is
#DE2AC3. The grayscale version is
#666666. A 20% lighter version of the original color is
#54FF6F, and Hex
#00A209 is the 20% darker color. If the color is saturated by 10%, you get
#1AE038. If the color is desaturated by 10%, the color
#28CA40 is obtained.