The hex color #3d9a8f is a dark color. The web-safe version is Hex
#339999. A complementary color is
#C26570. The grayscale version is
#777777. A 20% lighter version of the original color is
#70CDC2, and Hex
#0A675C is the 20% darker color. If the color is saturated by 10%, you get
#379D91. If the color is desaturated by 10%, the color
#43978D is obtained.