The hex color #31b4a8 is a light color. The web-safe version is Hex
#33CC99. A complementary color is
#CE4B57. The grayscale version is
#848484. A 20% lighter version of the original color is
#64E7DB, and Hex
#008175 is the 20% darker color. If the color is saturated by 10%, you get
#29B9AC. If the color is desaturated by 10%, the color
#39AFA4 is obtained.