How to Fix Weird Mybb White Screen Glitch?

So I am developing a forum dedicated to youtubepoops http://utubepoop.com/

But the issue is my forum USED to be red (see below) when I changed my admin directory name for security reasons my forum turned white and glitchy.

A support member on mybb told me to go to global c.ss and hit save. https://community.mybb.com/thread-208050.html I did it sort of solved the problem but now my forum is set at default blue I tried to reset it to the default red theme but it would not work.

Now posts look weird too http://utubepoop.com/forumdisplay.php?fid=4

Thank you very much for your help and time