{% if page.series %}

{% assign count = '0' %}
{% assign idx = '0' %}
{% for post in site.posts reversed %}
    {% if post.series == page.series %}
        {% capture count %}{{ count | plus: '1' }}{% endcapture %}
        {% if post.url == page.url %}
            {% capture idx %}{{count}}{% endcapture %}
        {% endif %}
    {% endif %}
{% endfor %}
<div class="panel post-series">
    <p>
        This article is <strong>Part {{ idx }}</strong> in a <strong>{{ count }}-Part</strong> Series.
    </p>
    <ul class="list-group">
        {% assign count = '0' %}
        {% for post in site.posts reversed %}
            {% if post.series == page.series %}
                {% capture count %}{{ count | plus: '1' }}{% endcapture %}
                <li class="list-group-item {% if page.url == post.url %}active{% endif %}">Part {{ count }} -
                    <a href="{{post.url}}">{{post.title}}</a>
                </li>
            {% endif %}
        {% endfor %}
    </ul>
</div>

{% endif %}