body
{

}

div#web
{
	position: absolute;
	top: 50%;
	left: 50%; 
	width: 600px;
	margin-left: -300px;
	height: 600px;
	margin-top: -300px;
	background-image: url(css_body_fondo.png);
	background-position: center center;
	background-repeat: no-repeat;
}