JSFiddle - React, Tailwind, and code Playground

by glee

HTML

<div class = "circle"></div>

CSS

html, body {
    height: 100%;
}
.circle {
    border-radius: 1000px;
    background-color: rgb(0, 162, 232);
}

JavaScript

function upd() {
    var h = $("body").height();
    $(".circle").height(h / 5);
    $(".circle").width(h / 5);
}
upd();
window.onresize = upd;