Some changes have been made that have affected a few people, perhaps quite a lot! Sadly it was done without letting most people know - including some of the mods.
The url to use now is
www.pprune.org not as before org/forums.
Also, if some style and colour is missing the 'trick' is to use Ctrl + F5 together and this will refresh the pages for you. It has worked well for many so far.
Another tip might be to empty your cache/ temp files and cookies. The latter reset themselves but its a personal choice.
Onward and upward!
Hope it helps anyway.