.topo-base {
	background-attachment: scroll;
	background-image: url(imagens/topo_base.gif);
	background-repeat: repeat-x;
	background-position: left top;
}
.bg-topo {
	background-attachment: scroll;
	background-image: url(imagens/bg_topo.gif);
	background-repeat: no-repeat;
	background-position: right top;
}