The hex color #3d99bd is a light color. The web-safe version is Hex
#3399CC. A complementary color is
#C26642. The grayscale version is
#868686. A 20% lighter version of the original color is
#70CCF0, and Hex
#0A668A is the 20% darker color. If the color is saturated by 10%, you get
#369BC2. If the color is desaturated by 10%, the color
#4497B8 is obtained.