The hex color #b31c2e is a dark color. The web-safe version is Hex
#CC3333. A complementary color is
#4CE3D1. The grayscale version is
#545454. A 20% lighter version of the original color is
#E64F61, and Hex
#800000 is the 20% darker color. If the color is saturated by 10%, you get
#BC162A. If the color is desaturated by 10%, the color
#AA2232 is obtained.