Let’s say I have css1.css and css2.css.
Just for the sake of keeping files organized and small on my file system / Source control I would like to split them up however in my content, I still want to use all the definitions in both files.
Rather than link reference both in my content page, can css1.css just make css2.css available.
Clearly you can include them all on your page with several nodes, but your best bet is probably a release process script/ant task/automated build process which can concatenate or merge the files based on some manifest or even simply the order of the file names.
You can do other things like compress the css at the same time – automatically optimising files for deployment!