JSFiddle - React, Tailwind, and code Playground

HTML

<h1>1</h1>

CSS

<style>html {
  display: grid;
  min-height: 100%;
}

body {
  margin: 0;
  display: grid;
  grid-template-columns: auto 1fr auto;
  grid-template-rows: min-content 1fr;
  grid-auto-flow: row dense;
  gap: 1em;
}

body>h1 {
  margin: 0;
  writing-mode: vertical-rl;
  transform: scale(-1);
  /* extra for curiosity*/
  text-shadow: 0  calc(-100vh + 3.2rem) darkgreen;

  animation: indent 3s infinite linear;
  overflow: hidden;
  white-space: pre;
  height: calc(100vh - 3.2rem);
  grid-column: 3;
  font-size: 30em;
}

@keyframes indent {
  to {
    text-indent: calc(100vh - 3.2rem);
  }