blog/themes/mytheme/layouts/partials/post_nav_links.html

{{- $pages := where site.RegularPages "Type" "in" site.Params.mainSections }}
{{- if and (gt (len $pages) 1) (in $pages . ) }}
<nav class="paginav">
  {{- with $pages.Next . }}
  <a class="prev" href="{{ .Permalink }}">
    <span class="title">« {{ i18n "prev_page" }}</span>
    <br>
    <span>{{- .Name -}}</span>
  </a>
  {{- end }}
  {{- with $pages.Prev . }}
  <a class="next" href="{{ .Permalink }}">
    <span class="title">{{ i18n "next_page" }} »</span>
    <br>
    <span>{{- .Name -}}</span>
  </a>
  {{- end }}
</nav>
{{- end }}