JSFiddle - React, Tailwind, and code Playground

HTML

<div class="header">Header</div>
<div class="content">

  <div class="wrap">
    <div class="container">
      <div class="article-1">
        <div class="card">
          <div class="card-text">
            scrollable flex: 1 div<br>
            1. scrollable<br>
            2. scrollable<br>
            3. scrollable<br>
            4. etc...
          </div>
        </div>
      </div>
      <div class="article-2">
        flex: none div
      </div>
    </div>
  </div>

  <div class="footer">Footer</div>
</div>

CSS

html, body{
  height: 100%;
  width: 100%;
  padding: 0;
  margin: 0;
  box-sizing: border-box;
  font-weight: bold;
}

.header {
  position: absolute;
  height: 40px;
  background-color: grey;
  z-index: 1;
  width: 100%;
}

.content {
  position: relative;
  display: flex;
  flex-direction: column;
  height: 100%;  
  width: 100%;
  padding-top: 40px;
}

.wrap {
  max-height: 100%;
  width: 100%;
  position: relative;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.container {
  height: 100%;
  width: 100%;
  padding: 10px;
  display: flex;
  flex-direction: column;
}

.article-1 {
  flex: 1;
  min-height: 300px;
  overflow: hidden;
}

.card {
  height: 100%;
  width: 100%;
  overflow: auto;
}

.card-text {
  height: 2000px;
  width: 2000px;
  background-color: red;
}

.article-2 {
  flex: none;
  height: 40px;
  background-color: blue;
}

.footer {
  position: relative;
  height: 40px;
  background-color: grey;
}