The hex color #3fd41e is a light color. The web-safe version is Hex
#33CC33. A complementary color is
#C02BE1. The grayscale version is
#666666. A 20% lighter version of the original color is
#72FF51, and Hex
#0CA100 is the 20% darker color. If the color is saturated by 10%, you get
#3BDF17. If the color is desaturated by 10%, the color
#43C925 is obtained.