*, html, body {margin:0; padding:0}
html, body, #contenedora{width:100%; height:100%; color:#333}
body {font:12px "Trebuchet MS", Verdana, Arial, Helvetica, sans-serif}
#contenedora{ position:absolute; top:0; left:0; width:100%; height:100%;}
#contenedor { position:absolute; left:50%; top:50%; width:1000px; height:700px; margin-left:-500px; margin-top:-350px; z-index:1;}