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 ;)