Reuze is a teeny-tiny front end framework that makes structuring HTML and CSS for mid-to-large sized content-rich sites a breeze. It plays nice with other frameworks such as Foundation and Boostrap but also works equally well on it's own.
Quickly create semantic HTML5 code blocks that conveniently sit in 'namespaced' containers ('.ac' for article content as an example) and download the accompanying 10KB (or less) of CSS awesomeness from Github. It's responsive, IE8-friendly and topped up with RDFa Lite goodness!