$(function() {
	$('.main_nav a')
		.css( {backgroundPosition: "0 0"} )
		.mouseover(function(){
			$(this).stop().animate({backgroundPosition:"(0 -52px)"}, {duration:300})
		})
		.mouseout(function(){
			$(this).stop().animate({backgroundPosition:"(0 0)"}, {duration:300, complete:function(){
				$(this).css({backgroundPosition: "0px 0px"})
			}})
		})
});