Highlight parent and ancestor menu items

Hello,
I’m using Nav Menu Field successfully at https://analyze.ch with a child theme of Twenty Twelve, custom menus based on pages, not posts/categories. Additionally, the first level navigation items are “Redirect to child” only. So far everything works. My only issue ist that I did not find out how to highlight parent and ancestor menu items. Fors instance, at https://analyze.ch/film/corporate/osteology-foundation/ I’d like to have FILM and CORPORATE highlighted (font-weight:bold). Have found a lot of forum discussions about that issue, but not in cennection with custom menus and Nav Menu Field. Every answer is highly appreciated, thx in advance.
Didier

https://www.ads-software.com/plugins/advanced-custom-fields-nav-menu-field/