a.infobox { 
  border-bottom: 1px dashed #c30;
  text-decoration:none; 
  color:blue;
}

a.infobox:hover {
  cursor:help;
  color:#c30;
  background:white;
}

a.infobox span {
  visibility:hidden;
  position:absolute;
  left:-99em;
  margin-top:1.5em;
  padding:1em;
  text-decoration:none;
}

a.infobox:hover span {
  visibility:visible;
  left:1em;
  top:1em;
  border:1px solid #c30;
  color:blue;
  background:white;
}