JSFiddle - React, Tailwind, and code Playground

HTML

<div id="left_panel">
    <div class="open_left">close MENU</div>
</div>
<div id="right_panel">
    <div class="open_right">RIGHT MENU</div>
</div>
<div id="container">
    <header>
        <div id="site-title">TEST SITE</div>
        <nav></nav>
    </header>
    <div id="body">
        <div id="ex_buttons">
            <ul>
                <li>
                    <div class="open_left"> <span>LEFT MENU</span>

                    </div>
                </li>
                <li>
                    <div class="backtotop"> <span>top</span>

                    </div>
                </li>
                <li>
                    <div class="open_right"> <span>RIGHT MENU</span>

                    </div>
                </li>
            </ul>
        </div>
        <div id="the-content"></div>
    </div>
    <footer>
        <copyright>test site.,co</copyright>
    </footer>
</div>

CSS

*, *:before, *:after {
    box-sizing: border-box;
}
html, body {
    font: normal 16px/100% sans-serif;
    margin:0;
    padding: 0;
}
#left_panel, #right_panel {
    height: 100%;
    width: 200px;
    background: #eee;
    display: none;
    color: #666;
    font-size: xx-large;
    position: fixed;
    top: 0;
    z-index:9;
}
#left_panel {
    float: left;
    left: 0;
}
#right_panel {
    float: right;
    right: 0;
}
#ex_buttons {
    position: fixed;
    bottom: 0;
    width: 100%;
    z-index: 99;
}
#ex_buttons ul {
    display: flex;
    flex-flow: row wrap;
    justify-content: space-between;
    margin: 0;
    padding: 0;
}
#ex_buttons li {
    flex: 1 auto;
    border: 1px solid #999;
    list-style-type: none;
    margin: 0;
    padding: 0;
    text-align: center;
    height: 3em;
    position: relative;
    background-color: #ccc;
}
#ex_buttons li span {
    display: block;
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 100%;
    font-size: 0.725rem;
}
/*ここから下、装飾とか色々*/
 header {
    background-color: #fff;
    height: 5em;
    border: 1px solid #000;
    overflow: hidden;
    position: relative;
}
header:before {
    content:"";
    width: 200px;
    height: 200px;
    position: absolute;
    background-color: #f00;
    border-radius: 50%;
    left: 50%;
    transform: translateX(-50%);
}
#site-title {
    font-size: 1.25rem;
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 100%;
    text-align: center;
}
nav {
    position: absolute;
    width: 100%;
    height: 1em;
    bottom: 2px;
    background-color: #000;
}
nav a {
    color: #fff;
    text-decoration: none;
}
nav ul {
    display: flex;
    flex-flow: row wrap;
    justify-content: space-around;
    margin: 0;
    padding: 0;
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
}
nav ul li {
    flex: 1 auto;
    list-style-type: none;
    text-align:center;
}
#left_panel nav {
    position: relative;
   ...

JavaScript

$('.open_left').click(function () {
    $("#left_panel").animate({
        width: 'toggle'
    }, 200);
});

$('.open_right').click(function () {
    $("#right_panel").animate({
        width: 'toggle'
    }, 200);
});

$("nav").clone().appendTo("#left_panel");

// -----------------------------------------------
// ここから下は記事を構成するために利用する分で必要ありません
// -----------------------------------------------

//make menu(like grobal menu)

$("nav").append("<ul></ul");

var dat = [
        {"href": 1, "name": "a"},
        {"href": 2, "name": "b"},
        {"href": 3, "name": "c"},
        {"href": 4, "name": "d"}
    ];

for (var i in dat) {
    $("nav ul").append("<li><a href='#" + dat[i].href + "'>menu_" + dat[i].name + "</a>");
}

//make post
$("#the-content").append("<div id='main'><p>便宜上メニューは表示してます</p><br/></div>");
$("#the-content").append("<div id='sidebar'></div>");

function isPrime(n) {
    if (isNaN(n) || !isFinite(n) || n % 1 || n < 2) return false;
    var m = Math.sqrt(n);
    for (var i = 2; i <= m; i++) if (n % i == 0) return false;
    return true;
}

function words(str, loop) {
    var out_str = "";
    for(var i=0; i < loop; i++){
        if (isPrime(i)){
            out_str += str + "<br />";
        } else {
            out_str += str + "&nbsp;";
        }
    }
    return out_str;
}

$("#main").append(words("あああああ", 100));
$("#sidebar").append(words("いいいいい", 50));