hugo-PaperMod/layouts/partials/footer.html

<footer class="footer">
    {{- if .Site.Copyright }}
    <span>{{ .Site.Copyright | markdownify }}</span>
    {{- else }}
    <span>&copy; {{ now.Year }} <a href="{{ "" | absLangURL }}">{{ .Site.Title }}</a></span>
    {{- end }}
    <span>&middot;</span>
    <span>Powered by <a href="https://gohugo.io/" rel="noopener noreferrer" target="_blank">Hugo</a></span>
    <span>&middot;</span>
    <span>Theme <a href="https://git.io/hugopapermod" rel="noopener" target="_blank">PaperMod</a></span>
</footer>

{{- if (not .Site.Params.disableScrollToTop) }}
<a href="#top" aria-label="go to top" title="Go to Top (Alt + G)">
    <button class="top-link" id="top-link" type="button" accesskey="g">
        <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 12 6" fill="currentColor">
            <path d="M12 6H0l6-6z" />
        </svg>
    </button>
</a>
{{- end }}

{{- partial "extend_footer.html" . }}

<script>
    window.onload = function () {
        if (localStorage.getItem("menu-scroll-position")) {
            document.getElementById('menu').scrollLeft = localStorage.getItem("menu-scroll-position");
        }
    }

    function menu_on_scroll() {
        localStorage.setItem("menu-scroll-position", document.getElementById('menu').scrollLeft);
    }

    document.querySelectorAll('a[href^="#"]').forEach(anchor => {
        anchor.addEventListener("click", function (e) {
            e.preventDefault();
            var id = this.getAttribute("href").substr(1);
            if (!window.matchMedia('(prefers-reduced-motion: reduce)').matches) {
                document.querySelector(`[id='${decodeURIComponent(id)}']`).scrollIntoView({
                    behavior: "smooth"
                });
            } else {
                document.querySelector(`[id='${decodeURIComponent(id)}']`).scrollIntoView();
            }
            if (id === "top") {
                history.replaceState(null, null, " ");
            } else {
                history.pushState(null, null, `#${id}`);
            }
        });
    });

</script>

{{- if (not .Site.Params.disableScrollToTop) }}
<script>
    var mybutton = document.getElementById("top-link");
    window.onscroll = function () {
        if (document.body.scrollTop > 800 || document.documentElement.scrollTop > 800) {
            mybutton.style.visibility = "visible";
            mybutton.style.opacity = "1";
        } else {
            mybutton.style.visibility = "hidden";
            mybutton.style.opacity = "0";
        }
    };

</script>
{{- end }}

{{- if (not .Site.Params.disableThemeToggle) }}
<script>
    document.getElementById("theme-toggle").addEventListener("click", () => {
        if (document.body.className.includes("dark")) {
            document.body.classList.remove('dark');
            localStorage.setItem("pref-theme", 'light');
        } else {
            document.body.classList.add('dark');
            localStorage.setItem("pref-theme", 'dark');
        }
    })

</script>
{{- end }}