The hex color #1a3d3f is a dark color. The web-safe version is Hex
#333333. A complementary color is
#E5C2C0. The grayscale version is
#323232. A 20% lighter version of the original color is
#4D7072, and Hex
#000A0C is the 20% darker color. If the color is saturated by 10%, you get
#183E40. If the color is desaturated by 10%, the color
#1C3C3E is obtained.