The hex color #3f6ecf is a dark color. The web-safe version is Hex
#3366CC. A complementary color is
#C09130. The grayscale version is
#7F7F7F. A 20% lighter version of the original color is
#72A1FF, and Hex
#0C3B9C is the 20% darker color. If the color is saturated by 10%, you get
#396CD7. If the color is desaturated by 10%, the color
#4570C7 is obtained.