Hey there! I'm currently working on a CLI tool to deploy WordPress apps to DigitalOcean. Check it out! It's free and open source.
One of my first experiments is the color wheel and there are plenty of jQuery plugins and code snippets that could do that. With a few more research about colors and their hex codes, I found a way to determine a color darker or lighter than the chosen once, enabling me to do the gradient fill, drop-down menu colors. The HSL values returned by the color wheel let me switch the font color, so that the text appears white on a dark background and black on a light one.
As you can see the color wheel not only affects the website header, but also the links on the page, giving them a darker color than the one chosen, giving a better contrast. Of course it is not perfect, but I’ll get there eventually ;)