body { background: #ccc; margin: 0; padding: 0; position: absolute; width: 100%; height: 100% }
#contenido { position: absolute; float: left; width: 780px; height: 472px; left: 50%; top: 50%; margin-left: -390px; margin-top: -236px }

body { font-family: "Trebuchet MS", Verdana, Arial, Helvetica, sans-serif }
a { font-size: 12px }
a:link { color: #666 }
a:hover { color: #333; text-decoration: none }
a:active { color: #036 }