The hex color #213a3c is a dark color. The web-safe version is Hex
#333333. A complementary color is
#DEC5C3. The grayscale version is
#323232. A 20% lighter version of the original color is
#546D6F, and Hex
#000709 is the 20% darker color. If the color is saturated by 10%, you get
#1F3B3D. If the color is desaturated by 10%, the color
#23393B is obtained.