H1 {
     text-align: center;
     }

H1.main:before {  
            content: url("http://www-gris.det.uvigo.es/~miguel/massai/images/ti_dessus.png");
            display: block;
            text-align: left;
            margin-left: 1em;
            }

H1.main:after{ 
          content: url("http://www-gris.det.uvigo.es/~miguel/massai/images/ti_dessous.png");
          display: block;
          text-align: left;
          margin-left: 1em;
 }

div.direccion {
  line-height: 1.1;
}

div.direccion p {
    font-family: sans-serif;
    text-align: left;
    text-indent: 0;
}

div.abstracto {
  font-family: monospace;
  border: 2px solid;
  padding: 1em;
  margin-left: 2%;
  margin-right: 2%;
  margin-top: 3ex;
  margin-bottom: 3ex;
  background: rgb(240,240,240);
  border-radius: 25px;
  -moz-border-radius: 25px;
}

p { 
 text-indent: 2em;
 text-align: justify;
}

p.footer {
  font-size: 80%;
  font-family: serif;
  text-indent: 0;
}

li p { 
      text-indent: 0;
}

img.valid {
  border: 0;
  width: 88px;
  height: 31px;
}

span.derecha {
  float: right;
  margin-right: 0px;
}

acronym 
{
  border-bottom-style: dashed;
  border-bottom-width: 1px;
  cursor: help;
}