so, it's basically just a sort of build tool plugin api.
can be used as a build tool plugin. uhm.
postcss-cli is a thing.
i guess probably most of the css things i use are available as plugins here anyway. (obviously autoprefixer and cssnext, but also probably) stylus (i hope), cssnano/csso, stylelint, bem/suit stuff, et-OH MY GOD A SEARCH ON THE WEBSITE SHOWS NO STYLUS PLUGINS WHAT oh wait it's okay a search on npm shows two, we're saved.