The hex color #687ec4 is a dark color. The web-safe version is Hex
#6666CC. A complementary color is
#97813B. The grayscale version is
#8E8E8E. A 20% lighter version of the original color is
#9BB1F7, and Hex
#354B91 is the 20% darker color. If the color is saturated by 10%, you get
#647CC9. If the color is desaturated by 10%, the color
#6C80BF is obtained.