JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="first"></div>
    <div class="second"></div>
</div>

CSS

div {
  display: flex;
}

.container {
    width: 100px;
    flex-wrap: wrap;
    background: blue;
}

.first {
    width: 150px;
    margin-bottom: 20px;
    background: green;
}

.second {
    width: 10px;
    height: 10px;
    background: red;
}

JavaScript

// The container (blue) correctly wraps the red box