I am modularizing my stylesheets with SASS partials like so:
If you are using Sass in a Rails project, the sass-rails gem, https://github.com/rails/sass-rails, features glob importing.
@import "foo/*" // import all the files in the foo folder @import "bar/**/*" // import all the files in the bar tree
To answer the concern in the accepted answer "If you import a directory, how can you determine import order? There's no way that doesn't introduce some new level of complexity."
Some would argue that organizing your files into directories can REDUCE complexity.
My organization's project is a rather complex app. There are 119 Sass files in 17 directories. These correspond roughly to our views and are mainly used for adjustments, with the heavy lifting being handled by our custom framework. To me, a few lines of imported directories is a tad less complex than 119 lines of imported filenames.
To address load order, we place files that need to load first – mixins, variables, etc. — in an early-loading directory. Otherwise, load order is and should be irrelevant... if we are doing things properly.