The hex color #181d3c is a dark color. The web-safe version is Hex
#003333. A complementary color is
#E7E2C3. The grayscale version is
#262626. A 20% lighter version of the original color is
#4B506F, and Hex
#000009 is the 20% darker color. If the color is saturated by 10%, you get
#171C3E. If the color is desaturated by 10%, the color
#191E3A is obtained.