JSFiddle - React, Tailwind, and code Playground

HTML

<div id="header">Header</div>
<div id="content">
    <div id="menudiv">
        <ul id="menu">
            <li><a href="">Home</a></li>
            <li><a href="">Products</a></li>
            <li><a href="">Clients</a></li>
            <li><a href="">Contacts</a></li>
        </ul>
    </div>
    <div id="cnt">
        <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Sed nobis labore vero recusandae velit iste tempora optio pariatur hic repellendus minima quia at assumenda eum culpa ex cum nisi rerum!</p>
    </div>
</div>

CSS

#header {
    width: 800px;
    height: 150px;
    background: #ccc;
    margin: 0 auto 10px;
    border-radius: 5px;
    padding: 10px;
}
#content{
    position: relative;
    width: 800px;
    background: #ccc;
    height: 500px;
    margin: 0 auto;
    border-radius: 5px;
    padding: 10px;
}
 
#cnt{}
 
#menudiv{
    _margin-left: -85px;
    margin-top:5px;
    width: 150px;
    height: 300px;
    float: left;
    position: relative;
}
 
#menu{
    list-style-type: none;
}
    #menu li {
        background: #bbb;
        display: block;
        margin-bottom: 10px;
        border-radius: 5px;
        padding: 5px;
        cursor: pointer;
    }
        #menu li a{
            text-decoration: none;
            color: #fff;
        }
     
    #menu li:hover {
        background: #07D8FF;
    }