The hex color #3d3f6d is a dark color. The web-safe version is Hex
#333366. A complementary color is
#C2C092. The grayscale version is
#4E4E4E. A 20% lighter version of the original color is
#7072A0, and Hex
#0A0C3A is the 20% darker color. If the color is saturated by 10%, you get
#3B3E70. If the color is desaturated by 10%, the color
#3F406A is obtained.