The hex color #721e37 is a dark color. The web-safe version is Hex
#663333. A complementary color is
#8DE1C8. The grayscale version is
#424242. A 20% lighter version of the original color is
#A5516A, and Hex
#3F0004 is the 20% darker color. If the color is saturated by 10%, you get
#771A36. If the color is desaturated by 10%, the color
#6D2238 is obtained.