The hex color #687ce5 is a light color. The web-safe version is Hex
#6666CC. A complementary color is
#97831A. The grayscale version is
#989898. A 20% lighter version of the original color is
#9BAFFF, and Hex
#3549B2 is the 20% darker color. If the color is saturated by 10%, you get
#6379ED. If the color is desaturated by 10%, the color
#6D7FDD is obtained.