The hex color #554ff9 is a dark color. The web-safe version is Hex
#6666FF. A complementary color is
#AAB006. The grayscale version is
#8A8A8A. A 20% lighter version of the original color is
#8882FF, and Hex
#221CC6 is the 20% darker color. If the color is saturated by 10%, you get
#5049FF. If the color is desaturated by 10%, the color
#5A55EE is obtained.