JSFiddle - React, Tailwind, and code Playground

HTML

<body>
  <div id="left">Left</div>
  
  <div id="right">
    <p>Right</p>
    <p>Right 2</p>
  </div>
</body>

CSS

body{
  font-size: 0;
}

#left, #right {
  font-size: 16px;
}

#left {
  display: inline-block;
  background: red;
  width: 20%;
  height: 100%;
  vertical-align: top;
}
#right {
  display: inline-block;
  background: green;
  width: 80%;
  height: 100%;
  vertical-align: top;
}