Website Turned Plain-Text After Accidental URL Change

I recently tried tochanged the URL in Settings > General from http://www.asquare.edu.hk to https://www.asquare.edu.hk but my site immediately crashed afterwards.

I have tried all solutions suggested in this Change URL Post.

1. I have tried adding a line at the wp-config.php file:

define('WP_HOME','http://asquare.edu.hk/content');
define('WP_SITEURL','http://asquare.edu.hk');

2. Also tried adding a line in the function.php file of the only template installed:

update_option('siteurl','http://asquare.edu.hk');
update_option('home','http://asquare.edu.hk/content');

3. I also went into phpMyAdmin and changed both the "siteurl" and "home" strings back to http:// but the site is still displaying as plain text at the moment.

Any advice would be greatly appreciated. Many thanks!