Variables in your CSS via PHP

There are a number of ways to use PHP with other web languages and technologies. I myself use PHP in some of my JS scripts and sometimes even in CSS files.
While surfing the net I found someone asking for a way to create ‘color variables’. I commented outlining a way that this could be accomplished using PHP, but it was of coure garbled since I was using < and > in my comment.

| Variables in your CSS via PHP.