body {background-color:#FFFFFF; margin:0; padding:0;}
#horizon {text-align:center; position:absolute; top:50%; left:0; width:100%; height:1px; overflow:visible; visibility:visible; display:block;}
#content {margin-left:-500px; margin-top:-290px; position: absolute; left:50%; width:720px; height:480px; visibility:visible;}