After updating to 2.2 my site appears to be functioning, but the admin login and control panel have no CSS applied. So the normal EE administrative UI does not appear.
I may have made an error during updating. I don’t know if this caused the problem:
One of the update steps is to restore
system/expressionengine/third_party/
system/expressionengine/templates/
themes/third_party/
from my backup. Instead, I may have copied these folders to the server from my local, fresh copy of 2.2 instead of from my backup.
Thinking that this might have happened, after the update, I copied these folders to the server from my backup. It didn’t fix the problem.
I don’t think I used any third party anything in this fairly new site, if it matters.
What to do?