JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
  <div class="outer">
    <div class="inner">
      <canvas class="canvas"></canvas>
    </div>
  </div>
  <div class="outer">
    <div class="inner">
      <canvas class="canvas"></canvas>
    </div>
  </div>

CSS

html, body {
  width: 100%;
  height: 100%;
  margin: 0;
}

.container {
  width: 100%;
  height: 100%;
  display: grid;
  grid-template-rows: 1fr 1fr;
  grid-template-columns: 1fr;
}

.outer {
  background-color: green;
  overflow: hidden;
}

.inner {
  background-color: blue;
  width: 100%;
  height: 100%;
}

.canvas {
  width: 4000px;
  height: 100px;
}