I'm not sure what you mean but here's a few ways of doing what I think you're asking.
index.php
<?php
$bgcolor='#fff';
include('./header.inc');
//page stuff
include('./footer.inc');
?>
Header.inc
<html>
<head>
<link rel="stylesheet" type="text/css" href="path/to/style.css" />
<style type="text/css">
/*because this is set after the stylesheet is included it will be the value*/
body {
background-color:<?php echo($bgcolor);?>;
}
</style>
</head>
<body>
Or I believe you can pass get variables to a css file and then call it .php and the variables will be picked up by php.
header.inc
<!-- etc -->
<link rel="stylesheet" type="text/css" href="path/to/style.php?bgcolor=fff" />
<!-- etc -->
style.php
body {
babground-color:#<?php echo($_GET['bgcolor']);?>;
}
I haven't ever tried the second method before but I'd be interested as to whether it works or not 🙂
HTH
Bubble