I've suddenly got multiple points of failure on a WordPress multisite:
There's no access to the backend at all, beyond the log-in screen there's a blank screen
Child theme stylesheets are only being partially applied
I haven't updated or added any plug-ins on WordPress for a couple of weeks: last thing I did was changed one site's child theme stylesheet, and left the whole thing working as normal.
Does anyone know what might be the cause, and how to fix it? Thanks!