How to centre navbar logo in Boostrap 4 with nav-links below - html

Question

I can't seem to get the navbar logo to centre align with the nav-links centre below it. I'm sure I'm missing something simple, I've checked out a few other posts regarding this issue but all seem to be using older versions of bootstrap. I am currently using bootstrap 4.0.
Specifically, I want the logo on its own separate row, not on the same one as the links.
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="#"><img src="img/h-tech-logo-cropped.png"/></a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarNav">
<ul class="navbar-nav">
<li class="nav-item">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Our Services</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">About Us</a>
</li>
<li class="nav-item">
<a class="nav-link disabled" href="#">Gallery</a>
</li>
<li class="nav-item">
<a class="nav-link disabled" href="#">Contact Us</a>
</li>
</ul>
</div>

Answer 1

It's a matter of using the flexbox and auto-margin utils as explained in the many other "Bootstrap 4 Navbar Center" questions...
The navbar is display:flex so use flex-column to make content stack
Use mx-auto for auto x-axis margins to center.
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" >
<script src="https://code.jquery.com/jquery-3.3.1.js" integrity="sha256-2Kok7MbOyxpgUVvAk/HJ2jigOSYS2auK4Pfzbm7uH60=" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" ></script>
<nav class="navbar navbar-expand navbar-light bg-light flex-column">
<a class="navbar-brand mx-auto" href="#"><img src="img/h-tech-logo-cropped.png"></a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarNav">
<ul class="navbar-nav">
<li class="nav-item">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Our Services</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">About Us</a>
</li>
<li class="nav-item">
<a class="nav-link disabled" href="#">Gallery</a>
</li>
<li class="nav-item">
<a class="nav-link disabled" href="#">Contact Us</a>
</li>
</ul>
</div>
</nav>
Responsive demo on Codeply
Related "Bootstrap 4 Navbar Center" questions:
Bootstrap NavBar with left, center or right aligned items
Bootstrap 4 navbar with 2 rows
Center an element in Bootstrap 4 Navbar
How to center nav-items in Bootstrap?