apache - Content-type not working in PHP

Question

I have some issues with a PHP file that is not working properly. The Content-type does not get recieved by any browser at all. Firebug interprets the file as text/html instead of css. Here's the file :

<?php
header('Content-Type: text/css; charset=UTF-8');
error_reporting(E_ALL | E_STRICT);
ini_set('display_errors', 'On');
/* CSS goes on from here */

I tested to put a row with echo 'TEST'; before the header line, and was expecting to see the classic "headers already sent" error, but nothing appears!

Normal .css-files are working like a charm however.

What can I do to sort this out?

UPDATE: Did change default_mimetype = "text/html" to default_mimetype = "text/css" in php.ini and all pages got immediately interpreted as css, so there's must be a way to just send css headers for this file :)

The full file from demand of John:

    <?php
    header('Content-Type: text/css; charset=UTF-8');
    echo 'body {background-color: #000000; }';
    ?>

UPDATE #2: Adding ini_set('default_mimetype', 'text/css'); to the PHP file fixes this file, but it doesn't solve the issue that causes this fault...

UPDATE #3: Tested adding AddType text/css .css to both .htaccess and Apache config. Still no luck. Also tested to send headers separated from charset: header('Content-Type: text/css'); - Still no luck...

UPDATE #4: Have reinstalled Apache+PHP at the server to see if the problem goes away, but no. Same old, same old...

Answer 1

Check your php.ini file for the output_buffering setting. If it's not set to "off" than PHP is automatically doing output buffering for you. Set that to off and echo something before the header command, and you should see the "classic error".

You shouldn't use the closing ?>. I know this is a controversial suggestion, but too many times people add a return and/or space after it, which gets output to the browser (before the header). There are very few cases where it not using it would cause a problem.