The hex color #637a7c is a dark color. The web-safe version is Hex
#666666. A complementary color is
#9C8583. The grayscale version is
#737373. A 20% lighter version of the original color is
#96ADAF, and Hex
#304749 is the 20% darker color. If the color is saturated by 10%, you get
#617B7D. If the color is desaturated by 10%, the color
#65797B is obtained.