body {
  align-items: center;
  display: flex;
  height: 100vh;
  justify-content: center;
}

a {
  border-bottom: 1px solid #453886;
  color: #453886;
  padding-bottom: .25em;
  text-decoration: none;
}

a:hover {
  background-image: url("https://s3-us-west-2.amazonaws.com/s.cdpn.io/9632/squiggle.svg");
  background-position: bottom;
  background-repeat: repeat-x;
  background-size: 20%;
  border-bottom: 0;
  padding-bottom: .3em;
  text-decoration: none;
}