The hex color #288da3 is a dark color. The web-safe version is Hex
#339999. A complementary color is
#D7725C. The grayscale version is
#737373. A 20% lighter version of the original color is
#5BC0D6, and Hex
#005A70 is the 20% darker color. If the color is saturated by 10%, you get
#2190A8. If the color is desaturated by 10%, the color
#2F8A9E is obtained.