The hex color #3f811f is a dark color. The web-safe version is Hex
#339933. A complementary color is
#C07EE0. The grayscale version is
#4A4A4A. A 20% lighter version of the original color is
#72B452, and Hex
#0C4E00 is the 20% darker color. If the color is saturated by 10%, you get
#3E861B. If the color is desaturated by 10%, the color
#407C23 is obtained.