The hex color #c90c1d is a dark color. The web-safe version is Hex
#CC0033. A complementary color is
#36F3E2. The grayscale version is
#515151. A 20% lighter version of the original color is
#FC3F50, and Hex
#960000 is the 20% darker color. If the color is saturated by 10%, you get
#D50518. If the color is desaturated by 10%, the color
#BD1322 is obtained.