JSFiddle - React, Tailwind, and code Playground

HTML

<div class="a box"></div>
<div class="b box">box with a height of 100px for comparison</div>

CSS

.box {
    padding: 10px;
    width: 100px;
    -moz-box-sizing: border-box;
    -webkit-box-sizing: border-box;
    -o-box-sizing: border-box;
    box-sizing: border-box;
    float: left;
}
.a {    
    height: 20px;
    background: #6dade8;
}

.b {
    background: #7762fa;
    height: 100px;
    color: white;
}

JavaScript

$('.a').height(100)