jQuery(document).ready(function(){
	var height = jQuery("#nav_main").height();
	jQuery("#header").prepend("<div id='nav_bg' style='position:absolute;top:125px;width:100%;height:" + height + "px;background-color:#fff;border-top: 1px #000 solid;border-bottom: 1px #000 solid;'/>");
	jQuery("#nav_bg").css("opacity","0.5");
});