$(function(){

    var $el, leftPos, newWidth,
        $mainNav = $("#main-nav");

    $mainNav.append("<li id='magic-line'></li>");
    
    var $magicLine = $("#magic-line");
    
    $magicLine
        .width($(".current_page_item").width())
        .css("left", $(".current_page_item a").position().left)
        .data("origLeft", $magicLine.position().left)
        .data("origWidth", $magicLine.width())
		.data("origColor", $(".current_page_item a").attr("rel"));
        
    $("#main-nav li").find("a").hover(function() {
        $el = $(this);
        leftPos = $el.position().left;
        newWidth = $el.parent().width();
        
        $magicLine.stop().animate({
            left: leftPos,
            width: newWidth,
			backgroundColor: $el.attr("rel")
        });
    }, function() {
        $magicLine.stop().animate({
            left: $magicLine.data("origLeft"),
            width: $magicLine.data("origWidth"),
			backgroundColor: $magicLine.data("origColor")
        });    
    });
});