The hex color #91e9ef is a light color. The web-safe version is Hex
#99FFFF. A complementary color is
#6E1610. The grayscale version is
#CECECE. A 20% lighter version of the original color is
#C4FFFF, and Hex
#5EB6BC is the 20% darker color. If the color is saturated by 10%, you get
#8BECF2. If the color is desaturated by 10%, the color
#97E6EC is obtained.