NB: I originally posted this on SO, but I was recommended to try here - sorry for the duplicate!
I'm really baffled about this. In the last couple of days (since I was using the site last), my Wordpress install has suddenly lost almost all of its formatting (only the top bar seems to work.
The CSS does seem to be loading, but its missing tons of them:
Here is the same page on another site (same version of WordPress);
I'm at a loss as to what could be causing this all of a sudden. The front end if fine, just to reiterate that.