JSFiddle - React, Tailwind, and code Playground

HTML

<div class="a">
  <div class="b">
  <div style="height: 500px; background-color: yellow"></div>
  </div>
</div>

CSS

.a {
  max-height: 200px;
  background: red;
  display: flex;
  flex-direction: row; /* or column */
}

.b {
  overflow: auto;
  background: blue;
  flex: 1 1 auto;
}