What a great, simple solution to off canvas menus.  And they work super fast as they are using CSS transitions instead of jQuery.  I read an article on Smashing Magazine that perhaps was a bit complex, even though the result was great, I still found it confusing to read.  This tutorial however, explains it clearly with a great image illustrating how it works.  Great post!

https://scotch.io/tutorials/off-canvas-menus-with-css3-transitions-and-transforms