$(document).ready(function(){
	$(window).resize(function(){
		var _t = $('#mainpage');
		var offset = _t.offset();
		bg_x = _t.width() + offset.left - 1068;
		bg_y = _t.height() + offset.top - 686;
		$("body").css("background-position",bg_x + "px "+ bg_y + "px");	
	});					   
})