JSFiddle - React, Tailwind, and code Playground

HTML

<div class="div1">
    <div class="div2"></div>
    <div class="div3"></div>
</div>

CSS

.div1 {
    display: table;
}
.div1 > div {
    border: 1px solid #000;
    width: 200px;    
    display: table-cell;
}
.div3 {
    height: 500px;
}