body{ 
<h3>fondo.jpg</h3>
background-image: url("fotos/fondo4.jpg");
font-family: Tahoma, Arial, Geneva, sans-serif; /*tipo de fuente*/
color:#black; /*color de fuente*/
background-image:url(fondo3.jpg);
}

#cabecera{ 
width: 100%; /*ancho*/
height: 100px; /*alto*/
text-align: center; /*alineación hor del texto*/
margin-bottom: 0px; /*margen externo inferior*/
background-image: url("fotos/turismoarg.jpg"); /*color de fondo*/
float:top; /*ubicación relativa del bloque*/
opacity: 0.8;
}

#navegacion{ 
width: 15%; 
height: 400px;
float: left; 
text-align: center;
font-style: italic;
/*padding: 3px;*/
margin-bottom: 0px;
background-color:#40B1CF;
float: left;
}

section{ 
width: 85%;
height: 400px;
text-align: center; 
margin-bottom: 0px; 
background-color:#5FA0AE;
float: right;

}

footer {
    position: relative;
    margin-top: 0px;
    height: 80px; 
    clear: both;
    background: #238FAC;
    text-align: center;
    color: #000000;
    background-image:url(fondo3.jpg);
}