for example, lets say i have a style sheet file called style.css and i want to get the value from a php file. well, just open the style.css file and save it as style.php, BUT, just make sure you put this code at the very top of the file:
<?php header("Content-type: text/css"); ?>
thats, it, this will make css file from php. i hope i showed you how to make css file from php, this way you can make php file into css files. isnt that great. with this tutorial, i showed you how to save php file into css. well, if you have any questions about changin a php file into css or css into php, here you go.
you can even take it a step further, buy using .htaccess file

