在尝试压缩css时，php脚本显示在css文件中

I have script below in my css file to compress the file but it dosn't compress the file and it show the php script when I am opening css file

PHP Script

 <?php
      header('Content-type: text/css', true);
      ob_start("compress");
      function compress($buffer) {
        // remove comments
        $buffer = preg_replace('!/\*[^*]*\*+([^/][^*]*\*+)*/!', '', $buffer);
        // remove tabs, spaces, newlines, etc.
        $buffer = str_replace(array("
", "", "
", "\t", '  ', '    ', '    '), '', $buffer);
        return $buffer;
      }
    ?>

... CSS style....

<?php ob_end_flush();?>

.htaccess

# compress text, html, javascript, css, xml:
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript

# Or, compress certain file types by extension:
<files *.html>
    SetOutputFilter DEFLATE
</files>

<Files *.css>
  SetHandler  application/x-httpd-php 
</Files>

Thanks.

Edit: In local computer (WAMP) it works fine.