toasted-cactus/layouts/404.html

<!DOCTYPE html>
<html lang="{{ with .Site.LanguageCode }}{{ . }}{{ else }}en-US{{ end }}">
    <head>
        {{ partial "head.html" . }}
    </head>
<body>
    {{ partial "nav.html" . }}

    <section id="wrapper" class="home">
        <article class="post">
            <header>
                <h1>404 - page not found</h1>
                <h3>The page you're looking for doesn't seem to exist.</h3>
            </header>

            {{ partial "archive.html" . }}
        </article>

        {{ partial "footer.html" . }}
    </section>
    </body>
</html>