JSFiddle - React, Tailwind, and code Playground

HTML

<div class="nav-content-wrapper">
      <div class="left-nav">asdasdasd ads asd ads asd ad asdasd ad ad a ad</div>
      <div class="content">asd as dad ads ads ads ad ads das ad sadsadsads da da ad ad </div>

    </div>

CSS

.nav-content-wrapper{position:relative; overflow:auto; display:block; background:yellow;height:300px;}
.left-nav{float:left;background:green;width:30%;height:inherit;}
.content{float:left;background:red;width:70%;height:inherit;}