jQuery(document).ready(

function(){   
	var bgPos = jQuery("#mainnav").css("background-position");
	function navbase(){jQuery("#mainnav").css("background-position",bgPos)}
	jQuery("#nav-art").hover(
		function(){jQuery("#mainnav").css({backgroundPosition:"0px -118px"})},
		function(){navbase()}
	);
	jQuery("#nav-code").hover(
		function(){jQuery("#mainnav").css("background-position","0px -231px")},
		function(){navbase()}
	);
	jQuery("#nav-design").hover(
		function(){jQuery("#mainnav").css("background-position","0px -344px")},
		function(){navbase()}
	);
	jQuery("#nav-all, #nav-home").hover(
		function(){jQuery("#mainnav").css("background-position","0px -457px")},
		function(){navbase()}
	);
}

);