JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html lang="en">

<head>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!--Author URL: https://codepen.io/andornagy/pen/RNeydj
Description: A Generic Hierarchical Menu Navigation
Version: 1-->
    <style>
        /* CSS Document */
        body {
            background: #212121;
            font-size: 22px;
            line-height: 32px;
            color: #ffffff;
            margin: 0;
            padding: 0;
            word-wrap: break-word !important;
            font-family: 'Open Sans', sans-serif;



        height: 100vh;
        /*100% of the viewport*/
        display: flex;
        flex-direction: column;
    }

    main#content {
        flex: 1;
        overflow-y: scroll;
    }

    h1 {
        font-size: 60px;
        text-align: center;
        color: #FFF;
    }

    h3 {
        font-size: 30px;
        line-height: 34px;
        text-align: center;
        color: #FFF;
    }

    h3 a {
        color: #FFF;
    }

    ul {
        list-style-type: none;
    }

    nav>ul {
        display: flex;
    }

    nav>ul>li {
        position: relative;
    }

    nav>ul>li>ul {
        padding: 0;
        top: 100%;
        left: 0;
        position: absolute;
    }

    input:checked~ul {
        display: block;
    }

    button::after {
        content: '\25bc';
    }

    li:focus-within>button::after {
        content: '\25b2';
    }

    a {
        color: #FFF;
    }

    h1 {
        margin-top: 100px;
        text-align: center;
        font-size: 60px;
        line-height: 70px;
        font-family: 'Bree Serif', 'serif';
    }

    #container {
        margin: 0 auto;
        max-width: 890px;
    }

    p {
        text-align: center;
    }

    /* Giving a background-color to the nav container. */
    nav {
        margin: 0;
        padding: 0;
        background-color: #E64A19;
    }

    #logo {
        display: block;
        padding: 0 30px;
        float: left;
        font-size:...