The hex color #d81c31 is a dark color. The web-safe version is Hex
#CC3333. A complementary color is
#27E3CE. The grayscale version is
#626262. A 20% lighter version of the original color is
#FF4F64, and Hex
#A50000 is the 20% darker color. If the color is saturated by 10%, you get
#E4152C. If the color is desaturated by 10%, the color
#CC2336 is obtained.