Make parent menu items active when a user is on a page inside the custom mega menu content

There are links inside the custom content of the mega menu. When I visit a page that is linked in the mega menu, this link should have an “active” class so that I can visually highlight the link in the mega menu. There should be a tighter integration with hooked elements to let the theme know which menu items are present, so it can handle them appropriately (including the parent option). We'd also require styling options for the default, hover, and active states of the menu items.