Messed up backend - Installation error (HTML App)

If you see your backend messed up like this, then the problem in almost every case is, that the url variable is wrong inside your config.php file. You should make sure, that it looks like this:

public static $url = 'http://nextenddev.no-ip.org/gabor/html/';

so it is containing the whole link to your website, to the folder where you put our files, and then run the installation again.