It's doing it for me now, too. Don't know if that was a caching issue, but I can now reproduce the issue on all three major browsers. I was able to play around with some web developer tools to find the problem. It appears that the
load.php being served is full of encoded garbage on most pages on the wiki (not all; some, such as the recent changes page, are okay) which causes most of the styling to fail. I made a local copy of the load.php file from the recent changes page and imported it into the main page and everything worked correctly when I did so. dislekcia will need to look into why load.php isn't coming back correctly on every page.
FYI, the Wiki is still completely functional, it's just the styling information is missing. The underlying content and functionality appears to be unaffected. If you absolutely must see the wiki correctly, use the following steps:
(note: instructions are for the firefox browser).
1) Got to the
recent changes page on the wiki. You'll notice the page is good.
2) Hit Shift-F7 to open the style editor. (tools->web developer->style editor, if hotkeys aren't your thing)
3) on the left-hand side of your screen you should see a list of files. Find load.php and save it to your computer (you may want to change the name, since it's pretty generic).
4) Go to page of the wiki you want to view normally and hit Shift-F7 to open the style editor on that page
5) select load.php and click "import", selecting the good file you saved from the recent changes page
The page should now display normally, using the correct load.php information.