The hex color #303f6c is a dark color. The web-safe version is Hex
#333366. A complementary color is
#CFC093. The grayscale version is
#494949. A 20% lighter version of the original color is
#63729F, and Hex
#000C39 is the 20% darker color. If the color is saturated by 10%, you get
#2E3E70. If the color is desaturated by 10%, the color
#334069 is obtained.