bugfix: Firefox mobile navbar (dropdown parents without a URL couldn't be opened)

[medjakub]

On mobile Firefox, tapping a dropdown parent that has no page of its own (Students, Attending) did nothing useful. Those items were rendered as with the expand arrow as a nested inside the anchor, so tapping the arrow both toggled the submenu checkbox and fired the empty-href navigation — and Firefox resolved that in favor of navigating, so the submenu never opened.

On top of that, the arrow-rotation rule (input:checked + .drop-icon) never actually matched, since the drop-icon isn't an adjacent sibling of the checkbox in our markup.

Changes:

• Dropdown parents with no URL now render as a (toggle only, no navigation); real links stay as .
• Switched the arrow-rotation selector to .menu__dropdown:has(> input:checked) so it matches the actual structure.
• Moved the mobile hover/active background from .menu__item to .menu__link so only the tapped row highlights.

[dgnad]

Works like a charm. Many thanks!

[medjakub]

FYI, I've found a nice solution by Kevin (@kzhe0012) in the repository of ICAPS 2024 webpage. It is currently under review to be merged to ICAPS 2027 webpage. We may switch to this fix as well, but given the conference is over, it might not be worth the time (since the previous fix is already in).

[dgnad]

I've also made the 2027 chairs aware that merging the change would be nice. Either solution is fine, I guess. For the 2026 page there is probably no need to make it "nicer" :)