For some CSS work I need a global CSS file (not a specific one like account.css), but for registered users only. Meaning the file should never be loaded to the browsers cache of guests, but always be loaded to the browsers cache of registered users.
Does such file exist? If no, is it possible to create one myself?
Arty's suggestion require that you have a file called registered.css in your root directory, my suggestion require you to create a template called registered.css in the ACP. The easiest way to see if it is working is to check your website source, mine would appear in the css.php?css=....., Arty's would appear as a separate line.
Yeah, that is the html specification, the syntax Arty suggested above is a xF specific implementation to load templates. As Arty pointed out, both are the same, one is just closer to the html syntax, so it is easier to remember.