Parent navigation dropdown styling

Hello, I am trying to find a solution to highlight the parent navigation of my dropdown menu, when a child page is selected. The parent also contains a link to a page that is not in the dropdown.

I have tried using the code provided in this topic(Highlighting Parent Dropdown on "Current" - #4 by samliew). After this, I added the styling for the dropdown-active class. I did this via custom code. When inspecting the page, the class is added to the < a > tag with the parent link when I am on a child page, but no styling is shown.

I’ve tried changing the class name and adding it to the < div > tag that contains the < a > tag, but still no effect.

What could cause this styling to not show up?