Hi , I just upgrade from 6.5.x to 7.2
But it doesn't generate CSS , my site is just pure text. I don't know why.

When testing ubbt 7.1 , I can see ubbthreads_xxxxxxxx.css in styles/ directory.
But I cannot find such a file in styles directory. It's permission is correctly set to 777.
What may cause the problem ???

English is not my native language. I try my best to express my thought precisely. I hope you understand what I mean. If any misunderstanding results from culture gaps, I apologize first.