body {
    margin-left: 10%;
    margin-right: 10%
    }
.pn {
    text-indent: 0;
    text-align: right;
    color: silver
    }
.prosa p {
    text-align: justify;
    text-indent: 1em
    }
.prosa p.centrado {
    text-align: center;
    text-indent: 0
    }
h1 {
    text-align: center;
    margin-top: 5em;
    margin-bottom: 5em;
    border-top: solid 3px #000;
    border-bottom: solid 3px #000;
    padding: 1em
    }
h2, h3 {
    text-align: center;
    margin-top: 3em;
    margin-bottom: 2em
    }
hr {
    border: 0;
    border-bottom: solid 2px
    }
a {
    text-decoration: none
    }