CSS.PHP -file indentation problem

I need to code my CSS inside PHP-files (e.g. pages.css.php). I can successfully turn on the Template Data Languages -> CSS for these files so they get the proper syntax coloring.

However, indentation does not work. If I try to reformat the code, it formats PHP-code fine but not CSS.

Is there a possibility to turn on proper indentation for CSS (or other languages in Template Data Languages).
I Have a PHPStrom 6.0.3 personal licence.


pages.css.php:

<?php
  header("Content-type: text/css;charset=utf-8");
?>

#wrapper {
position: relative;
width: 960px;
margin: 0 auto;
box-shadow: 0 0 36px #333;
background: #fff;
}

. . .