The hex color #51a916 is a dark color. The web-safe version is Hex
#669900. A complementary color is
#AE56E9. The grayscale version is
#5B5B5B. A 20% lighter version of the original color is
#84DC49, and Hex
#1E7600 is the 20% darker color. If the color is saturated by 10%, you get
#50B10F. If the color is desaturated by 10%, the color
#52A11D is obtained.