The hex color #3d66d2 is a dark color. The web-safe version is Hex
#3366CC. A complementary color is
#C2992D. The grayscale version is
#7C7C7C. A 20% lighter version of the original color is
#7099FF, and Hex
#0A339F is the 20% darker color. If the color is saturated by 10%, you get
#3764DB. If the color is desaturated by 10%, the color
#4368C9 is obtained.