#fondo {
  position: fixed;
  margin: 0px;
  border: 0px;
  padding: 0px;
  left: 0px;
  top: 0px;
  width: 100%;
  height: 100%;
  overflow: hidden;
  z-index: 0;
}
#fondo img {
            width: 100%; height:100%;
            }
						
#cuerpo {
  position: absolute;
  left: 8%;
  top: 12%;
  width: 80%;
  height:80%;
  z-index: 10;
overflow:auto;}

h3{text-align:center;color:yellow}


div.izquierda{float: left; width:350px;background-color:navy; color:white; cursor: pointer}
div.derecha{float: right; width:350px;background-color:navy; color:white; cursor: pointer}