The hex color #eff23e is a light color. The web-safe version is Hex
#FFFF33. A complementary color is
#100DC1. The grayscale version is
#B5B5B5. A 20% lighter version of the original color is
#FFFF71, and Hex
#BCBF0B is the 20% darker color. If the color is saturated by 10%, you get
#F5F832. If the color is desaturated by 10%, the color
#E9EC4A is obtained.