Body becomes a flex column so the header takes its natural height and the
main container fills the rest via flex:1 — replaces the brittle
calc(100vh - 70px) that assumed a 70px header and broke as soon as the
header wrapped on mobile. Adds 100dvh fallback for iOS Safari address
bar quirks.
Mobile breakpoint (≤900px) reworked: list scrolls internally via
list-content max-height:50vh, detail-panel uses overflow:visible so the
whole document scrolls naturally instead of nesting scrollers. Tapping
an item auto-scrolls to the detail panel and a new "← Zur Liste" button
(mobile-only) jumps back. Adds a tighter ≤600px breakpoint that hides
the subtitle, collapses the matrix grid to one column and shrinks the
matrix table for phone screens.
Resolves issue #6.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
