The hex color #a0100f is a dark color. The web-safe version is Hex
#990000. A complementary color is
#5FEFF0. The grayscale version is
#404040. A 20% lighter version of the original color is
#D34342, and Hex
#6D0000 is the 20% darker color. If the color is saturated by 10%, you get
#AA0B0A. If the color is desaturated by 10%, the color
#961514 is obtained.