.muestra{
    height: 300px;
    width: 400px;
    border: 5px solid #C00;
    margin: 20px;
    padding: 20px;
}
.anterior, .posterior{
    height: 100px;
    width: 200px;
    border: 2px solid #30F;
    padding: 5px;
}
div{
    background: url(../imagenes/f01.png) left bottom repeat-x,
    url(../imagenes/f02.png) left bottom no-repeat,
    url(../imagenes/f03.png) left top repeat-x;
    background-color: #a4d3ff;
}
.anterior a{
    text-decoration: none;
}
.posterior a{
    text-decoration: none;
}