a[rel=external] {
  border-bottom-style: dashed;
  border-bottom-width: 1px;
  position: relative;
  text-decoration: none;
}

a[rel=external]:after {
  content: "External Link";
  position: absolute;
  bottom: 130%;
  left: 20%;
  background: #ebd6b7;
  padding: 5px 15px;
  color: black;
  -webkit-border-radius: 10px;
  -moz-border-radius : 10px;
  border-radius : 10px;
  white-space: nowrap;
  opacity: 0;
  -webkit-transition: all 0.4s ease;
  -moz-transition : all 0.4s ease;
  transition : all 0.4s ease;
}

a[rel=external]:before {
  content: "";
  position: absolute;
  width: 0;
  height: 0;
  border-top: 20px solid #ebd6b7;
  border-left: 20px solid transparent;
  border-right: 20px solid transparent;
  -webkit-transition: all 0.4s ease;
  -moz-transition : all 0.4s ease;
  transition : all 0.4s ease;
  opacity: 0;
  left: 30%;
  bottom: 90%;
}

a[rel=external]:hover:after {
  bottom: 100%;
}

a[rel=external]:hover:before {
  bottom: 70%;
}

a[rel=external]:hover:after, a:hover:before {
  opacity: 1;
}