The hex color #b4303c is a dark color. The web-safe version is Hex
#CC3333. A complementary color is
#4BCFC3. The grayscale version is
#606060. A 20% lighter version of the original color is
#E7636F, and Hex
#810009 is the 20% darker color. If the color is saturated by 10%, you get
#BC2B38. If the color is desaturated by 10%, the color
#AC3540 is obtained.