NN/g mega-menu hover protocol: wait 0.5s before showing, then display within 0.1s

Quote (Jakob Nielsen, NN/g):

"Wait 0.5 seconds. If the pointer is still hovering over a navbar item, display its mega menu within 0.1 seconds."

Source: https://www.nngroup.com/articles/mega-menus-work-well/

Confidence: Verified.

Why this matters: Mega menus that fire instantly on hover flicker open as the cursor passes over the nav. The 500ms delay prevents flicker; the 100ms reveal is fast enough to feel responsive. Implementation note for Candid sites: use setTimeout(show, 500) with cancellation on mouseleave. Touch users get an immediate response on tap (no hover state). See RULE: Mega menu hover delay 500ms before show, 100ms reveal. Mobile uses accordion / sequential, not the same mega menu..