.fondos {
	background-attachment: scroll;
	background-image: url(graficos/fondo1.jpg);
	background-repeat:    repeat-x;
	background-position: center top;
}
.fondo-2 {
	background-attachment: fixed;
	background-image: url(graficos/fondo-2.jpg);
	background-repeat:  repeat-x;
	background-position: center top;
}