The hex color #3651a5 is a dark color. The web-safe version is Hex
#336699. A complementary color is
#C9AE5A. The grayscale version is
#646464. A 20% lighter version of the original color is
#6984D8, and Hex
#031E72 is the 20% darker color. If the color is saturated by 10%, you get
#314FAC. If the color is desaturated by 10%, the color
#3B539F is obtained.