SSL Breaks WordPress CSS

Paste the following line in your wp-config.php

if ($_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https') $_SERVER['HTTPS']='on';

but make sure that you do it before the following line

require_once(ABSPATH . 'wp-settings.php');

Read More: https://realprogrammer.in/ssl-breaks-wordpress-css/