Checkbox issue - Something is missing


I need to customize checkboxes. I read on the forum, I find an article and an example:

  1. Article: Styling Checkboxes in Webflow. One seemingly small feature missing… | by Stephanie Bardwil | No Excuses | Medium
  2. Example:

I followed the tutorial, and I tried reverse engineering but I don’t find a solution to add a new div block into the checkbox. Even on the cloned project, when I try to add a new div block (or the same div block) into the checkbox parent it doesn’t work.

I think I miss something, can anyone explain me how it is work?

Thank you!