The hex color #404b6f is a dark color. The web-safe version is Hex
#333366. A complementary color is
#BFB490. The grayscale version is
#535353. A 20% lighter version of the original color is
#737EA2, and Hex
#0D183C is the 20% darker color. If the color is saturated by 10%, you get
#3E4A72. If the color is desaturated by 10%, the color
#424C6C is obtained.