JSFiddle - React, Tailwind, and code Playground

HTML

<div id="snippet-container">
  <div id="page">
    <div id="content">
      <div class="test"></div>
    </div>
    <div id="footer"></div>
  </div>
</div>

CSS

#snippet-container {
  height: 300px;
  width: 200px;
}

#page {
  display: flex;
  flex-flow: column;
  height: 100%;
}

#content {
  display: flex;
  height: 100%;
  background: blue;
}

#content .test {
  width: 100%;
  height: 100%;
  background: yellow;
  border: 2px solid red;
}

#footer {
  flex: 0 1 10vh;
  background: black;
}