The hex color #257c6c is a dark color. The web-safe version is Hex
#336666. A complementary color is
#DA8393. The grayscale version is
#5A5A5A. A 20% lighter version of the original color is
#58AF9F, and Hex
#004939 is the 20% darker color. If the color is saturated by 10%, you get
#207F6E. If the color is desaturated by 10%, the color
#2A796A is obtained.