The hex color #51a320 is a dark color. The web-safe version is Hex
#669933. A complementary color is
#AE5CDF. The grayscale version is
#5C5C5C. A 20% lighter version of the original color is
#84D653, and Hex
#1E7000 is the 20% darker color. If the color is saturated by 10%, you get
#50AA1A. If the color is desaturated by 10%, the color
#529C26 is obtained.