In Bootstrap 4, the navbar-expand-*
class is needed to show the horizontal navbar, otherwise it will collapse into it’s mobile state.
Make sure you’ve referenced it properly in the Codepen as https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css
Or, use Codeply, and it will include the all the relevant libraries for you:
Bootstrap 4 on Codeply
Here’s the Navbar with Bootstrap 4.0.0:
http://www.codeply.com/go/SmEyy7rg5S
<nav class="navbar navbar-expand-md navbar-light bg-faded">
<button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarNavAltMarkup" aria-controls="navbarNavAltMarkup" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<a class="navbar-brand" href="#">Navbar</a>
<div class="collapse navbar-collapse" id="navbarNavAltMarkup">
<div class="navbar-nav">
<a class="nav-item nav-link active" href="#">Home <span class="sr-only">(current)</span></a>
<a class="nav-item nav-link" href="#">Features</a>
<a class="nav-item nav-link" href="#">Pricing</a>
<a class="nav-item nav-link disabled" href="#">Disabled</a>
</div>
</div>
</nav>