The hex color #3d566c is a dark color. The web-safe version is Hex
#336666. A complementary color is
#C2A993. The grayscale version is
#555555. A 20% lighter version of the original color is
#70899F, and Hex
#0A2339 is the 20% darker color. If the color is saturated by 10%, you get
#3B566E. If the color is desaturated by 10%, the color
#3F566A is obtained.