Fix stacked display of categories without children in catalogue browse template
{% if tree_categories %}
<h4>{% trans "Show results for" %}</h4>
<div class="side_categories card card-body bg-light">
- <ul class="nav nav-list">
+ <ul class="nav nav-list flex-column">
{% for tree_category in tree_categories %}
<li class="mt-2">
<a href="{{ tree_category.url }}">
