The hex color #558e8f is a dark color. The web-safe version is Hex
#669999. A complementary color is
#AA7170. The grayscale version is
#7B7B7B. A 20% lighter version of the original color is
#88C1C2, and Hex
#225B5C is the 20% darker color. If the color is saturated by 10%, you get
#519091. If the color is desaturated by 10%, the color
#598C8D is obtained.