JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE HTML>
<html>
<head>
  <title>Untitled</title>
<!--  <link rel="stylesheet" href="stylesheet.css" type="text/css" /> -->
<style>
* {
  margin: 0;
  padding: 0;
}

#master {
    position: relative;
    width: 940px;
    height: 600px;
    margin: auto;
    border: 1px solid #CC0000;
}

#header {
    height: 200px;
    border: 1px solid #CC0000;
}

#nav_bar {
    height: 30px;
    border: 1px solid #CC0000;
}
</style>
</head>
<body>
    <div id="master">master
        <div id="header">header</div>
        <div id="nav_bar">nav_bar</div>        
    </div>
</body>
</html>