JSFiddle - React, Tailwind, and code Playground
HTML
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.3/umd/popper.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/css/bootstrap.min.css">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/animate.css/3.5.2/animate.css">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
<html>
<body>
<head>
</head>
<div class="dark-layer">
<div class="container">
<nav class="navbar navbar-expand-lg">
<div class="container">
<a class="navbar-brand text-light" href="#">
Logo
</a>
<button class="navbar-toggler collapsed text-light" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
Expand
</button>
<div class="navbar-collapse collapse mr-auto" id="navbarSupportedContent">
<ul class="navbar-nav mr-auto">
<li class="nav-item"><a href="#" class="nav-link text-light">Link 1</a></li>
<li class="nav-item"><a href="#" class="nav-link text-light">Link 2</a></li>
<li class="nav-item"><a href="#" class="nav-link text-light">Link 3</a></li>
</ul>
</div>
</div>
</nav>
</div>
<div>
<div class="container">
<h1>
Some header
</h1>
<p>
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fusce eleifend tincidunt tellus, at ultrices erat bibendum a. Donec eget tortor tempus, dapibus eros fringilla, ultricies quam. Vivamus quis...
CSS
html {
height:100%
}
body {
background-image: url(https://images.pexels.com/photos/770151/pexels-photo-770151.jpeg?w=1260&h=750&auto=compress&cs=tinysrgb);
background-position: center;
background-repeat: no-repeat;
background-size: cover;
background-attachment: fixed;
padding: 0 auto;
margin: 0 auto;
}
.dark-layer{
background-color: rgba(0,0,0,.6);
height:100%;
width:100%;
}