andwati.com/templates/partials/post-nav.html

{% if page.lower or page.higher %}
<nav class="post-nav" aria-label="Post navigation">
  {% if page.higher %}
  <a class="post-nav-link post-nav-prev hover-scale" href="{{ page.higher.permalink }}">
    <span class="post-nav-label">&larr; {{ config.extra.post_nav_prev_label | default(value="Previous") }}</span>
    <span class="post-nav-title">{{ page.higher.title }}</span>
  </a>
  {% endif %}

  {% if page.lower %}
  <a class="post-nav-link post-nav-next hover-scale" href="{{ page.lower.permalink }}">
    <span class="post-nav-label">{{ config.extra.post_nav_next_label | default(value="Next") }} &rarr;</span>
    <span class="post-nav-title">{{ page.lower.title }}</span>
  </a>
  {% endif %}
</nav>
{% endif %}