.contenedor {
	font-family: Arial, Helvetica, sans-serif;
}
.capa1 {
	height : 817px;
	width: 740px;
	position: absolute;
	left: 0px;
	top: 0px;
	z-index: 1;
}
.capa1 img { 
    filter: alpha(opacity=100); 
	-moz-opacity:1.0;
}
.capa2 {
	height: 817px;
	width: 740px;
	position: absolute;
	left: 0px;
	top: 0px;
	z-index: 2;
}
.capa2 img {
    filter: alpha(opacity=100); 
	-moz-opacity:1.0;
}
.capa3 {
	height: 817px;
	width: 740px;
	position: absolute;
	left: 0px;
	top: 0px;
	z-index: 3;
}
.capa3 img {
    filter: alpha(opacity=90); 
	-moz-opacity:0.9;
}

//hack para ie 6 png transparente
.capa-con-png {
    background:url('capacarreteras.png');
}
* html .capa-con-png {
    background-image: none; /* Esta linea es importante, lo vemos mas abajo */
    filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(src='capacarreteras.png', sizingMethod='scale');
}