leilukin-site/src/_includes/main/content-nav.njk

<aside class="right-sidebar">
    <nav class="content__nav sidebar--sticky">
        <h2 class="content__nav--title">Content Index</h2>
        <ul class="content__nav--links">
            {% for archive in collections.archive %}
                <li><a href="{{ archive.url }}">{{ archive.data.title }}</a></li>
            {% endfor %}
            <li><a href="/articles/">Articles</a></li>
            {% for page in collections["blog pages"] %}
                <li><a href="{{ page.url }}">{{ page.data.navTitle or page.data.title }}</a></li>
            {% endfor %}
        </ul>
    </nav>
</aside>

<style>
    .content__nav {
        padding-left: 0.5em;
    }

    .content__nav--title {
        font-size: 1.7rem;
    }
</style>