Btw., if I remember correctly I actually used the code from one of your suggestions regarding the current links etc. found here: Current pseudo classes on sub pages
Maybe I am missing something here. In addition to adding the code, do I also need to follow your suggested steps:
Move the parent pages back to the root (no folders).
/services - Parent page with link in the menu
/services/services-page - Child page in the subfolder, subfolder has with same slug as parent page /services
Re-publish your site.
If possible maybe you could take a look and let me know what kind of adjustments I need to make in order to highlight sub-pages when the site is self hosted. As mentioned before, everything works fine in the Webflow environment.