The hex color #5b51a5 is a dark color. The web-safe version is Hex
#666699. A complementary color is
#A4AE5A. The grayscale version is
#707070. A 20% lighter version of the original color is
#8E84D8, and Hex
#281E72 is the 20% darker color. If the color is saturated by 10%, you get
#594EAA. If the color is desaturated by 10%, the color
#5D54A0 is obtained.