@mahryekuh Thanks for the nudge! I double-checked the menu HTML for my in-progress site conversion, and on mobile it uses <button> for expanding menu headings (which are *not* links in their own right) and <ul> <li> <a> for the actual menu content and links; and on desktop it uses just <ul> <li> <a> lists; so I guess I should be OK. Both with styling through CSS.
(My currently-online web site is slightly different because Reasons.)
I'm really *trying* to do the right thing!