JSFiddle - React, Tailwind, and code Playground

HTML

<section class="top">
    <div class="left side">
        <h1>test</h1>
        <p>some content</p>
    </div>
    <div class="right side">
        <h2>aside content</h2>
        <p>some aside content</p>        
        <p>some aside content</p>
    </div>
</section>
<section class="bottom">
</section>

CSS

.top{ display:table; width:100%;}
.top .side { display:table-cell; padding:0 .5em;}
.top .left { width:60%;  background:#f1f1f1;}
.top .right { width:40%;}

.bottom{
    width: 100%;
    height:100px;
    background:#d1d1d1;
}