The hex color #237FD3 is a dark color. The web-safe version is Hex
#3366CC. A complementary color is
#DC802C. The grayscale version is
#7C7C7C. A 20% lighter version of the original color is
#56B2FF, and Hex
#004CA0 is the 20% darker color. If the color is saturated by 10%, you get
#1A7FDC. If the color is desaturated by 10%, the color
#2C7FCA is obtained.