The hex color #3951a1 is a dark color. The web-safe version is Hex
#336699. A complementary color is
#C6AE5E. The grayscale version is
#646464. A 20% lighter version of the original color is
#6C84D4, and Hex
#061E6E is the 20% darker color. If the color is saturated by 10%, you get
#354FA7. If the color is desaturated by 10%, the color
#3D539B is obtained.