treadingsoftly

NuclearMoose,
Thank-you very much for the welcome and the prompt advice, but, unless I’ve misunderstood your suggestion, it won’t work. Editing my index.php to read @import url(http://localhost/blog/wp-layout.css); ensures that when loaded on my server index.php can find the stylesheet. But when loaded elsewhere on the net, it searches the net reader’s own localhost in vain (I checked this on my dial-up connection). Replacing the URL with a relative reference (@import url(wp-layout.css) allows index.php to find the stylesheet both on my server and on the internet. The problem then is that this is far from the only place that the php code makes reference to the URIs as specified in WordPress ‘Options’. Not only are their multiple such references within index.php itself, but they litter all the other php files. For example, I could change all incidences of get_settings('siteurl') to relative links within index.php. But if the reader clicks on ‘register’, (s)he is taken to wp-register.php, informed that registration is disabled, and presented with a handy ‘home’ link that is thoroughly broken, as it points at http://localhost/blog/index.php. And that’s only the reader’s experience – trying to administer or post to the blog involves many more php files that link back to the main page.
So I think I need a more holistic solution as I can’t see myself changing all the php files everytime I reinstall or upgrade WordPress. I realise this isn’t necessarily a WordPress problem (although obviously it would help if there was a WordPress solution); perhaps I need to do some special network routing or fiddling with Apache, so that I could put the internet URLs into WordPress ‘Options’ and my server would know what to do with them (i.e. not direct me to my router’s admin page)?