JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html>
    <head>
        <meta name="charset" content="utf-8" />
        <title>Hi</title>
    </head>
    <body>
        <aside class="sidebar">
            sidebar
        </aside>
        <section class="content">
            content
        </section>
    </body>
</html>

CSS

html,
body {
  height: 100%;
}

body {
  position: relative;
  background: #eee;
}

.sidebar {
  width: 20%;
  height: 100%;
  background: #ccc;
  float: left;
}

.content {
  margin-left: 25%;
  background: #aaa;
  height: 100%;
}