The hex color #2b3f5b is a dark color. The web-safe version is Hex
#333366. A complementary color is
#D4C0A4. The grayscale version is
#424242. A 20% lighter version of the original color is
#5E728E, and Hex
#000C28 is the 20% darker color. If the color is saturated by 10%, you get
#293F5E. If the color is desaturated by 10%, the color
#2D3F58 is obtained.