Why don't I get any CSS after deploying my Drupal site? I have deployed my Drupal 8 website, but I don't get any CSS on it.

I deployed it on mydomain.com/newdrupal, maybe this needs extra configuring somewhere?



When I check my logs, I have about 20 messages with this warning:


  Warning: file_put_contents(temporary://filedGJSiQ): failed to open
  stream: "Drupal\Core\StreamWrapper\TemporaryStream::stream_open" call
  failed in file_unmanaged_save_data() (line 888 of
  /var/www/stijnAerts/notify/core/includes/file.inc).


I also have this in my console:


  Resource interpreted as Stylesheet but transferred with MIME type
  text/html: "*****/notify/?o66rbh".


Note: This is a base theme, so no custom theme.
In addition to @acrosman:

Make sure that your files and temporary files directories are writable by the server.