Change Theme Color

Hi

How do I change the theme color to a color that is not one of the six standard colors?

For example, if I wanted to change the theme color to a shade of grey, with the color code #77777

Thanks

Ps. please explain it as simply as possible!!

You need to know a little bit about css, then You can take one of current theme color files, and replace colors with tour own.
If You go to template folder /css, there are style1-6.css files. It is of them that You need to edit.