Native <dialog> opened from the TopStrip ? icon via useUIStore.aboutOpen.
Ref-driven showModal()/close() in useEffect, onClose synced to the store
so Escape closes both the dialog and the store flag in one round trip
(no listener fight). Three short paragraphs: the meme origin, the data
sources, and the keyboard shortcuts. The kbd-styled spans (mono +
1px --fg-4 outline) call out F and Esc.
No animation on open/close beyond the browser's default <dialog>
showModal transition (which is OS UI, not decoration). No backdrop-click
to close — Escape and the close button are enough; backdrop-click adds
a fragile target===dialog comparison for marginal value. ::backdrop
gets a 60% black tint so it reads as a modal, not a layer cake.
prose line-height 1.4 (looser than the 1.25 table tightness because
prose needs readability — operator-density still applies but Tufte
data-ink isn't violated by paragraph leading).
Plan 5 Task 23 Design QA: no illustration, no confetti, no tooltip
arrows, monochrome border, native ::backdrop only.