<nav id="nav-below" class="navigation" role="navigation">
    <h3 class="assistive-text">文章导航</h3>
    {% if page_obj.has_next  and next_url%}
        <div class="nav-previous"><a
                href="{{ next_url }}"><span
                class="meta-nav">&larr;</span> 早期文章</a></div>
    {% endif %}
    {% if page_obj.has_previous and previous_url %}
        <div class="nav-next"><a href="{{ previous_url }}">较新文章
            <span
                    class="meta-nav">→</span></a>
        </div>
    {% endif %}
</nav><!-- .navigation -->