Fbootstrapp by Clemens Krack, based on Bootstrap, from Twitter
ckrack.github.io/fbootstrapp
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
Fbootstrapp is a toolkit designed to kickstart development of facebook iframe apps in both relevant sizes. It includes base CSS and HTML for typography, forms, buttons, tables, grids, navigation, and more, styled in the typical facebook look and feel.