The workflow I have been using for personal projects is:
1. Design & Style using functional CSS (MelangeCSS in my case)
2. Use CSS for pseudo selectors and other speciality stuff
3. Manage re-use through HTML templates where possible
4. Create classes to manage re-use if HTML templates aren't the right fit
Steps 3 and 4 are often skipped if no need.
The result is a mix of functional CSS and Regular CSS, so I get the fast feedback of functional but some level of maintainability.