The hex color #3d3fd2 is a dark color. The web-safe version is Hex
#3333CC. A complementary color is
#C2C02D. The grayscale version is
#6F6F6F. A 20% lighter version of the original color is
#7072FF, and Hex
#0A0C9F is the 20% darker color. If the color is saturated by 10%, you get
#383ADC. If the color is desaturated by 10%, the color
#4244C8 is obtained.