The hex color #34404c is a dark color. The web-safe version is Hex
#333333. A complementary color is
#CBBFB3. The grayscale version is
#404040. A 20% lighter version of the original color is
#67737F, and Hex
#010D19 is the 20% darker color. If the color is saturated by 10%, you get
#33404D. If the color is desaturated by 10%, the color
#35404B is obtained.