The hex color #3f18a2 is a dark color. The web-safe version is Hex
#330099. A complementary color is
#C0E75D. The grayscale version is
#535353. A 20% lighter version of the original color is
#724BD5, and Hex
#0C006F is the 20% darker color. If the color is saturated by 10%, you get
#3D12AA. If the color is desaturated by 10%, the color
#411E9A is obtained.