JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
  <div class="heading-tab">
    <p class="heading-text">Heading One</p>
  </div>

  <div class="list-container">
    <div class="list">
      <ul>
        <li>One</li>
        <li>Two</li>
        <li>Three</li>
        <li>One</li>
        <li>Two</li>
        <li>Three</li>
        <li>One</li>
        <li>Two</li>
        <li>Three</li>
        <ul>
    </div>
  </div>
</div>

CSS

.container {
  display: flex;
  height: 72px;
}

.heading-tab {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  width: 294px;
  border-top: 1px solid lightgrey;
  background-color: #eee;
}

.heading-text {
  padding-top: 22px;
  padding-bottom: 22px;
  padding-left: 32px;
  margin-bottom: 0px;
  font-size: 16px;
}

.list-container {
  background-color: #aaa;
  width: 100%;
  overflow-y: scroll;
}