portfolio/_includes/post-paginator.html

{% if paginator.total_pages > 1 %}
<nav aria-label="Page Navigation">
  <ul class="pagination">
    <!-- left arrow -->
    {% if paginator.previous_page %}
      {% assign prev_url = paginator.previous_page_path | prepend: site.baseurl %}
    {% else %}
      {% assign prev_url = '' %}
    {% endif %}

    <li class="page-item {% unless paginator.previous_page %}disabled{% endunless %}">
      <a class="page-link" href="{{ prev_url }}" aria-label="previous-page">
        <i class="fa fa-angle-left"></i>
      </a>
    </li>

    <!-- right arrow -->
    {% if paginator.next_page_path %}
      {% assign next_url = paginator.next_page_path | prepend: site.baseurl %}
    {% else %}
      {% assign next_url = '#' %}
    {% endif %}

    <li class="page-item {% unless paginator.next_page_path %}disabled{% endunless %}">
      <a class="page-link" href="{{ next_url }}" aria-label="next-page">
        <i class="fa fa-angle-right"></i>
      </a>
    </li>
  </ul>
</nav>
<!-- .pagination -->
{% endif %}