The hex color #21b2cc is a light color. The web-safe version is Hex
#3399CC. A complementary color is
#DE4D33. The grayscale version is
#8A8A8A. A 20% lighter version of the original color is
#54E5FF, and Hex
#007F99 is the 20% darker color. If the color is saturated by 10%, you get
#16B6D3. If the color is desaturated by 10%, the color
#2CAEC5 is obtained.