hugo-site/layouts/404.html
{{ partial "head.html" }}
<body class="flex-body">
{{ partial "nav.html" }}
<section id="page404">
<div class="shadow-box-error">
<h1 class="error">404</h1>
<h2 class="sub-head">Not Found<span class="joke">just like my purpose in life...</span></h2>
</div>
</section>
</body>
</html>