The hex color #51a824 is a dark color. The web-safe version is Hex
#669933. A complementary color is
#AE57DB. The grayscale version is
#5F5F5F. A 20% lighter version of the original color is
#84DB57, and Hex
#1E7500 is the 20% darker color. If the color is saturated by 10%, you get
#50AF1E. If the color is desaturated by 10%, the color
#52A12A is obtained.