The issue with the forums being on the white background is from people in the latest browsers that enforce the latest mixed content warnings. Chrome on Mac is one of these.
PG-HQ and the forums are being served as https
(
https://pg-hq.com/comms/forumdisplay.php?fid=4)
BUT in the source code you are calling the CSS with http:
Since you are serving in HTTPS and the resource is HTTP it is a mixed content page and the modern browsers won't show it without a warning, or in Chrome on my computer it simply won't load them.
To test this if you can reproduce it, get the bad page, click in the address bar and change HTTPS to HTTP and they work fine
Here is the console with the warnings:
Not to be a PITA but this is a pretty easy error to fix. You could do a search in your IDE for http: and then probably change it to https: