{% for category in site.data.categories %}
  {% if category.slug == page.category %}
    {% assign category_name =  category.name %}
  {% endif %}
{% endfor %}

<h1 class="page-title">
    <div class="page-title-text">{{ category_name }}</div>
    <div class="page-title-subtitle">Articles in the category <strong>‘{{ category_name }}’</strong></div>
</h1>