JSFiddle - React, Tailwind, and code Playground

HTML

<div class="notify">
    <div>
        12
    </div>
</div>

CSS

body
{
    position: relative;
}

.notify
{
    position: absolute;
    top: 100%;
    left: 20%;
    background: red;
    border: 2px solid white;
    border-radius: 50%;
    text-align: center;
}

.notify > div
{
    padding: 20px;
}

JavaScript

var $elem = $(".notify > div");
var maxSize = Math.max($elem.width(), $elem.height());

$elem.width(maxSize).height(maxSize);