sioux-offscreen/style.css

An off screen navigation item. Similar to the menu of the Facebook and Path app

.offscreen {
	z-index: 40;
}

.offscreen ~ .onscreen {
	z-index: 60;
}

.offscreen, .offscreen ~ .onscreen {
	-webkit-transition-property: -webkit-transform;
	-webkit-transition-timing-function: cubic-bezier(0.175, 0.885, 0.32, 1);
	-webkit-transition-duration: .4s;
}