Implements the Top 5 fixes from the Stage-0 UX review (docs/ux-review/UX-REVIEW.md):
1. Dark mode: full light+dark custom-property palette (bg/fg/muted/line/accent/
card) under :root + @media (prefers-color-scheme: dark), applied to body.
color-scheme: light dark is now actually honoured — summary text was invisible
on a dark canvas before.
2. Table -> responsive card list: one card per summary (title link, channel·date
meta, provider chip, fallback badge, action state). Single-column reflow at
375px, no horizontal crush.
3. Minimal design system: 4/8px spacing scale, one accent, styled accent links
(underline-on-hover), real buttons with active/pressed state, consistent
radius and dividers — applied across list + detail.
4. Detail page as a reader: prose capped at 38rem, title->meta->summary->
highlights->takeaways hierarchy with section rules, 1.7 line-height. Meta is
built from non-empty parts (detailMeta) so the no-video edge case no longer
renders a stray "· — ·".
5. Contrast + a11y: muted bumped to #595959 (~7:1, clears WCAG AA), fallback
badge gets vertical padding + aria-label/title, friendly first-run empty
state, hx-indicator on the filter form.
Tests updated for the card markup (table -> cards); missing date is now omitted
rather than em-dashed. task check green; HTMX action toggles verified working.
mathias
d9b7107ccb