hugo-PaperMod/layouts/partials/header.html

{{- if eq .Site.Params.defaultTheme "auto" }}
<script>
    // load memory
    if (localStorage.getItem("pref-theme") === "dark") {
        document.body.classList.add('dark');
    } else if (localStorage.getItem("pref-theme") === "light") {
        document.body.classList.remove('dark')
    } else {
        if (window.matchMedia('(prefers-color-scheme: dark)').matches) {
            document.body.classList.add('dark');
        }
    }
</script>
{{- end }}
<header class="header">
    <nav class="nav">
        <p class="logo">
            <a href="{{ "" | absLangURL }}">{{ .Site.Title }}</a>
            {{- if not .Site.Params.disableThemeToggle }}
            <span class="theme-toggle">
                <a id="theme-toggle">
                    <svg id="moon" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"
                        fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round"
                        stroke-linejoin="round">
                        <path d="M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z"></path>
                    </svg>
                    <svg id="sun" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"
                        fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round"
                        stroke-linejoin="round">
                        <circle cx="12" cy="12" r="5"></circle>
                        <line x1="12" y1="1" x2="12" y2="3"></line>
                        <line x1="12" y1="21" x2="12" y2="23"></line>
                        <line x1="4.22" y1="4.22" x2="5.64" y2="5.64"></line>
                        <line x1="18.36" y1="18.36" x2="19.78" y2="19.78"></line>
                        <line x1="1" y1="12" x2="3" y2="12"></line>
                        <line x1="21" y1="12" x2="23" y2="12"></line>
                        <line x1="4.22" y1="19.78" x2="5.64" y2="18.36"></line>
                        <line x1="18.36" y1="5.64" x2="19.78" y2="4.22"></line>
                    </svg>
                </a>
            </span>
            {{- end}}
        </p>
        {{- $currentPage := . }}
        <ul class="menu" id="menu" onscroll="menu_on_scroll()">
            {{- range .Site.Menus.main }}
            {{- $menu_item_url := .URL | relLangURL }}
            {{- $page_url:= $currentPage.RelPermalink | relLangURL }}
            <li>
                <a href="{{ .URL | absLangURL }}">
                    <span {{- if eq $menu_item_url $page_url }}
                        {{- /* the menu item links to the current page (with relLangURL) */}} class="active" {{- end }}>
                        {{ .Name }}
                    </span>
                </a>
            </li>
            {{- end }}
        </ul>
    </nav>
</header>