The hex color #3d5d5f is a dark color. The web-safe version is Hex
#336666. A complementary color is
#C2A2A0. The grayscale version is
#535353. A 20% lighter version of the original color is
#709092, and Hex
#0A2A2C is the 20% darker color. If the color is saturated by 10%, you get
#3B5E60. If the color is desaturated by 10%, the color
#3F5C5E is obtained.