The hex color #a90a37 is a dark color. The web-safe version is Hex
#990033. A complementary color is
#56F5C8. The grayscale version is
#4E4E4E. A 20% lighter version of the original color is
#DC3D6A, and Hex
#760004 is the 20% darker color. If the color is saturated by 10%, you get
#B20335. If the color is desaturated by 10%, the color
#A01139 is obtained.