body,
html {
  height: 100%;
  margin: 0;
  background-image: url("image.webp");
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
  height: 100%;
}

div {
  line-height: 1.5;
  display: inline-block;
  vertical-align: middle;
}