The hex color #231c31 is a dark color. The web-safe version is Hex
#333333. A complementary color is
#DCE3CE. The grayscale version is
#252525. A 20% lighter version of the original color is
#564F64, and Hex
#000000 is the 20% darker color. If the color is saturated by 10%, you get
#231B32. If the color is desaturated by 10%, the color
#231D30 is obtained.