*{margin:0; padding:0;}
#topbanner{clear:both; width:550px; height:220px; background:#FFFFFF; overflow:hidden; position:relative; margin:10px auto 10px auto;}
#slideshow{width:1100px; height:660px; overflow:hidden; position:relative;}
  #slideshow li{width:550px; height:220px; float:left; display:inline;}