The hex color #99fcef is a light color. The web-safe version is Hex
#99FFFF. A complementary color is
#660310. The grayscale version is
#D7D7D7. A 20% lighter version of the original color is
#CCFFFF, and Hex
#66C9BC is the 20% darker color. If the color is saturated by 10%, you get
#93FFF1. If the color is desaturated by 10%, the color
#9FF8ED is obtained.