flex/pelican/themes/Flex/templates/partial/pagination.html

{% if DEFAULT_PAGINATION %}
  <div class="pagination">
  {% if articles_page.has_next() %}
    <a class="btn float-left" href="{{ SITEURL }}/{{ articles_next_page.url }}">
      <i class="fa fa-angle-left"></i> {{ _('Older Posts') }}
    </a>
  {% endif %}
  {% if articles_page.has_previous() %}
    <a class="btn float-right" href="{{ SITEURL }}/{{ articles_previous_page.url }}">
      {{ _('Newer Posts') }} <i class="fa fa-angle-right"></i>
    </a>
  {% endif %}
  </div>
{% endif %}