hugo-theme-introduction/layouts/404.html

{{ partial "header.html" . }}

<div class="section" id="top"><!-- Parent section -->

    <div class="container hero is-medium has-text-centered fade-in one"><!-- Begin Title -->
    <h1 class="bold-title is-1">404</h1>
    </div><!-- End Title -->

<!-- Everything below fades in two! -->
<div class="section fade-in two">

    <div class="container"><!-- Begin Nav bar -->
    {{ partial "nav-single.html" . }}
    </div><!-- End Nav bar -->

    <div class="container fade-in two top-pad"><!-- Begin blurb -->
        Oops! Either you've found a bug (in which case, <a href="mailto:{{ .Site.Params.email }}">please tell me</a>) or you're just making things up. This page doesn't exist!
    </div><!-- End blurb -->

<div class="top-pad"><hr></div>
{{ partial "footer.html" . }}
</div><!-- End parent section -->