> The code is being run on mightysite.dom itself and it is known to itself.

It is a usual situation a server is behind the firewall, and its external name (like myserver.com) is known only to reverse proxy. In the corporative internet the server appears under a “cryptic” no-way-to-remember name.

But you are right: if it loads the images, it is not an issue for your environment.

The debug output should give you a clue if it tries to load any CSS at all.

Also a severe syntax error in CSS may fail the entire stylesheet – you’ll find traces of that (if any) in the log file.