The hex color #51879c is a dark color. The web-safe version is Hex
#669999. A complementary color is
#AE7863. The grayscale version is
#7C7C7C. A 20% lighter version of the original color is
#84BACF, and Hex
#1E5469 is the 20% darker color. If the color is saturated by 10%, you get
#4D889F. If the color is desaturated by 10%, the color
#558699 is obtained.