body {
background:transparent url('bidibu.jpg') repeat scroll center; /* Tutte le proprietà di background in un'unica dichiarazione! */
text-align:center;
margin:0;
padding:0 0 20px 0;
font-family:Arial, Helvetica, sans-serif;
font-size:0.8em;
color:#000000;
}

#container {
width: 100%; height: 100%; top: 0; left: 0;
background: url(bidibu.jpg) no-repeat center top; position: fixed; z-index: -1;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
}