.introduccion p:hover{
  background-color:#ee0000;
  text-decoration:none;
  color:#fff;
}

.introduccion a{
  text-decoration:none;
  color:#fff;
}

.introduccion p{
  margin-left:10px;
  margin-right:10px;
}

footer{
  position: relative;
  top: 250px;
}