How to target Sub-Category of Sub-Category I have 2 Main Groups of Categories, which themselves have Sub-Categories.
The Categories you see have checkboxes to filter entries below.
One Sub-Group has also Children (With Material/ Without Material) ->Screenshot.
I need to collapse these two groups (on click they open/close).
How can i target these Sub-sub-Category Groups?
Right now i use:  

{% ifchildren %}
 &lt;ul class="subcategory-list"&gt;
   {% children %}
 &lt;/ul&gt;
{% endifchildren %}


  

I tried some with siblings but cannot get it to work. I also need to add extra html fot the arrow to indicate the collapse and to open the sublist.
 If i add it right now, it gets added to all category-groups.
Thanks.
I'm not sure, but I think you might need to use level in your loop. 

{% set categories = craft.categories.group('groupHandle').level(3) %}

{% for category in categories %}
    // etc
{% endfor %}


Have a look at the docs:

https://craftcms.com/docs/templating/craft.categories#level