#resumen {
    float: right;
    border: 1px dashed black;
    padding-left: 5px;
    padding-right: 5px;
    width: 600px;
    margin: 0px 50px;
    background: silver;
    text-align: justify;
    visibility: visible;
    display: block;
}

#resumen > h2 {
    text-align: center;
}