I love using Atomic CSS libraries like Tachyons, so much so that I've found writing plain old CSS to be a little more confusing, given that I think of properties as Tachyons classes now.
Therefore, I made this little script that generates a css.snippets file from a given CSS file for use with Vim and UltiSnips.
As an example, I've added an example-css.snippets file to this repo, which contains all the snippets generated from Tachyons.
Clone this repo and copy your CSS file into this folder.
Run the following (replacing library.css with the name of your CSS file).
npm install
node script.js library.css
It will generate a css.snippets file that you can paste into your usual snippets directory. I use UltiSnips so for me its ~/.vim/UltiSnips/snippets but your directory may be different.
This isn't perfect. Especially when using it for large libraries like I did with tachyons, you get a bunch of useless snippets that you may not need. I couldn't think of a way to automate this step so if you see some you don't need just go ahead and delete them.