.linea_grigia {
	background-attachment: fixed;
	background-image: url(immagini/punto_grigio.gif);
	background-repeat: repeat-x;
	background-position: center top;
}
.mappa {
	background-attachment: fixed;
	background-image: url(immagini/cartina_sfo.jpg);
	background-repeat: no-repeat;
	background-position: center top;
}