Twelve-Space is a structure system for creating layouts for web apps created by Kevin Mack. This presentation will give you an introduction to Twelve-Space, how to use it and how to expand on it.
Twelve-Space is a Sass-based, BEM, OOCSS open source framework. The project can be used for reuse, design patterns and rapid prototyping in the browser.
For the technical parts of the presentation, it is recommended that you have knowledge of Sass (focus on placeholder selectors and extend functionality) and BEM.