The hex color #1a3d3d is a dark color. The web-safe version is Hex
#333333. A complementary color is
#E5C2C2. The grayscale version is
#313131. A 20% lighter version of the original color is
#4D7070, and Hex
#000A0A is the 20% darker color. If the color is saturated by 10%, you get
#183E3E. If the color is desaturated by 10%, the color
#1C3C3C is obtained.