The hex color #c13e3e is a dark color. The web-safe version is Hex
#CC3333. A complementary color is
#3EC1C1. The grayscale version is
#6A6A6A. A 20% lighter version of the original color is
#F47171, and Hex
#8E0B0B is the 20% darker color. If the color is saturated by 10%, you get
#CA3A3A. If the color is desaturated by 10%, the color
#B84242 is obtained.