html,
body,
div {
  width: 100vw;
  height: 100vh;
  margin: 0px;
  padding: 0px;
}
div {
  display: table-cell;
  text-align: center;
  vertical-align: middle;
  font-size: 3rem;
  padding-bottom: 20vh;
  line-height: 5rem;
}