JSFiddle - React, Tailwind, and code Playground

HTML

<div class="root">
  <div class="scroll-container">
    <div class="flex-container">
      <p>Lorem ipsum dolor sit amet. Consectetur adipiscing elit. Nam sodales quam nunc.</p>
      <p>Donec condimentum elit in quam ultricies aliquet nec sed sapien.</p>
      <p>Mauris non erat sit amet ex blandit dignissim.</p>
      <p>Suspendisse vitae orci eu mauris fringilla posuere.</p>
      <p>Pellentesque feugiat pretium efficitur.</p>
    </div>
  </div>
</div>

CSS

.root {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  background: gray;
  
  display: flex;
  justify-content: center;
  align-items: center;
}

.scroll-container {
  margin: auto;
  max-height: 100%;
  overflow: auto;
}

.flex-container {
  display: flex;
  flex-direction: column;
  justify-content: center;
  background: white;
  height: 400px;
  width: 600px;
}