JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
</head>

<body>
    
    <div id="wrapper">
        <div id="header">
         HEADERj
        </div>
        
        <div id="menu">
        MENU
        </div>
        
        <div id="content">
        CONTENT
        </div>
    </div>
    
</body>
</html>

CSS

#wrapper
{
    height:600px;
    width:955px;
    margin:auto;
    background-color:#000;
}

#header
{
    float:left;
    height:100px;
    width:955px;
    background-color:#EEE;
}

#menu
{
    float:left;
    height:500px;
    width:100px;
    background-color:#EEE;
    border-top:solid 2px;
    
}

#content
{
    float:left;
    height:500px;
    width:855px;
    background-color:#999;
}