Off Canvas Sidebar Nav Pattern
All off canvas patterns solve the problem of space, by placing some content off screen until needed. In this pattern the navigation is off canvas left when the page first loads on smaller screens.
In its place a single menu button that when clicked slides the menu in and the content mostly off screen right. The click event is controlled with a checkbox that's positioned far off the screen.
Source : http://source.tutsplus.com/webdesign/tutorials/014_rwd-nav-patterns-4/demo/sidebar-nav.html