I'm sure I'm not the first person to come up against this issue, but I have not managed to find a simple solution yet. I have a number of sites on a multi-site installation, some of which use the Garland theme. Most of these Garland-based sites need a few minor CSS tweaks but do not (yet) need the full flexibility afforded by having their own Garland-derived themes separate from the global site's Garland.
I just don't see a good way to do this. So far, I have been copying Garland into each site's
themes directory and just adding an extra stylesheet import to
page.tpl.php. The obvious problem with this scenario (aside from the overhead of copying the entire theme) is that when the global site's themes are updated (when a new release of Drupal comes out), then I have to go through each site and merge in any changes to Garland.
I can picture a few ways to go about this, but it seems like somebody must have solved this problem in some way. One approach would be to develop a very simple module that did nothing but do a
drupal_add_css in whatever hook makes sense. Another approach would be to just modify the global Garland theme to include (if it exists) a file in a predictable location, like
The (brand new?) Alter CSS module does not seem to be designed with this multi-site scenario in mind. I noticed in my Googling that Bryght has an option that seems to be exactly what I want, but I can't tell if that's coming from some module I might be able to use on my own site.