Board Thread:Support Requests - Designing Your Wiki/@comment-1807002-20190801032029/@comment-9605025-20190804003629

Add a second class to the div in your template. Then appropriately add that second class to your CSS selectors. Essentially you want to do it so that collapsible parts that have that class in addition to "mw-collapsible" are impacted by the CSS. For example: 

Then you CSS would be: