Constructed from a nav containing nested dropdowns; each dropdown containing child pages is preceded by a direct link to the appropriate intro page. Each level of dropdown has its own class (level1, level2, level3). The dropdown toggles are not visible on desktop pages; the dropdown toggle text elements are not used on smaller screens either.
level3 dropdowns have CSS columns=2 by default, with .is-cols-1 or .is-cols-x classes used to set a different class where appropriate.