Yes it's possible. In fact this is how we do it at our company.
A CSS just needs a valid path. it doesn't matter from where it is hosted as long as path is accessible.
Just make sure you have valid settings under Settings -> Content -> Media -> Security
You need to make sure that your font extension is listed here. Otherwsie you won't be be upload your file under Media Libraries.
After this see it's relative path from the media library after uploading your files and use them in your css and you are all set.
I hope this helps.