The hex color #3fd40f is a light color. The web-safe version is Hex
#33CC00. A complementary color is
#C02BF0. The grayscale version is
#616161. A 20% lighter version of the original color is
#72FF42, and Hex
#0CA100 is the 20% darker color. If the color is saturated by 10%, you get
#3CE007. If the color is desaturated by 10%, the color
#42C817 is obtained.