<?php
define('CSSPATH', 'template/css/'); //define css path
$cssItem = 'style.css'; //css item to display
?>
<html>
<head>
<title>Including css</title>
<link rel="stylesheet" href="<?php echo (CSSPATH . "$cssItem"); ?>" type="text/css">
</head>
<body>
...
...
</body>
</html>