// Fixing position for header
Event.observe(window, 'load', function() {
	var header = $('header'),
		viewport = document.viewport;
	
	Event.observe(window, 'scroll', function() {
		if(viewport.getScrollOffsets().top >= 220) {
			Element.addClassName(header, 'fixed');
		} else {
			Element.removeClassName(header, 'fixed');
		}
	});
});