takahe/templates/activities/_bookmark.html

{% if post.pk in bookmarks %}
    <a title="Unbookmark" class="active" hx-trigger="click, keyup[key=='Enter']" hx-post="{{ post.urls.action_unbookmark }}" hx-swap="outerHTML" tabindex="0">
        <i class="fa-solid fa-bookmark"></i>
    </a>
{% else %}
    <a title="Bookmark" hx-trigger="click, keyup[key=='Enter']" hx-post="{{ post.urls.action_bookmark }}" hx-swap="outerHTML" tabindex="0">
        <i class="fa-regular fa-bookmark"></i>
    </a>
{% endif %}