If you are using Internet Explorer 7 or higher...

...or any other contemporary browser - Firefox, Opera, Safari, etc., then the background of this page will be green, and this means that the linked CSS file 'screen.css' did load normally.

If you are using Internet Explorer 6 or lower...

...then the background of this page will be (probably) white, and this means that the linked CSS file 'screen.css' did not load.

See related blog post: English, Bulgarian.