The hex color #3b51cf is a dark color. The web-safe version is Hex
#3366CC. A complementary color is
#C4AE30. The grayscale version is
#747474. A 20% lighter version of the original color is
#6E84FF, and Hex
#081E9C is the 20% darker color. If the color is saturated by 10%, you get
#354ED8. If the color is desaturated by 10%, the color
#4154C6 is obtained.