JSFiddle - React, Tailwind, and code Playground

HTML

<div id="parent">
    <div class="child"></div>
    <div class="child"></div>
    <div class="child"></div>
    <div class="child"></div>
    <div class="c_b"></div>
</div>

CSS

#parent {
    background-color: #F00;
    width: 200px;
}
.child {
    width: 200px;
    height: 300px;
    float: left;
}
.c_b {
    clear: both;
}