Here’s what Typeset.css does:

It includes styles for ALL content-based semantic markup and resets layout-based styles (incorrectly) applied to user-generated content. It inherits font styles, allowing it to be dropped in anywhere on a page where content markup needs styles. It plays well with CSS resetters, normalizers bootstrappers, boilerplaters and other popular CSS frameworks. And it renders styles consistently across browsers.

This is basically a problem for every site I’ve ever done user generated content on. Good to see a quick, comprehensive solution.