The hex color #efe543 is a light color. The web-safe version is Hex
#FFCC33. A complementary color is
#101ABC. The grayscale version is
#B2B2B2. A 20% lighter version of the original color is
#FFFF76, and Hex
#BCB210 is the 20% darker color. If the color is saturated by 10%, you get
#F5EA38. If the color is desaturated by 10%, the color
#E9E04E is obtained.