<div class="item">
  💩
  <div>According to spec, scrollbars are assumed not to exist</div>
</div>
<!-- view this demo with fixed scrollbars -->

.item {
  position: absolute;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rosybrown;
}

body {
  height: 200vh;
}

div {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  font-size: 3rem;
  & div {
    font-size: 1.2rem;
  }
}