The hex color #ffff65 is a light color. The web-safe version is Hex
#FFFF66. A complementary color is
#00009A. The grayscale version is
#CCCCCC. A 20% lighter version of the original color is
#FFFF98, and Hex
#CCCC32 is the 20% darker color. If the color is saturated by 10%, you get
#FFFF5B. If the color is desaturated by 10%, the color
#FAFA6F is obtained.