[pitill0]

Station search results render every card immediately, including cards outside the viewport. Defer off-screen layout and painting with content-visibility: auto and responsive intrinsic height estimates.

Keep cards and search fields within their panels, center the version footer across the shell, and attach the sidebar collapse control to the sticky menu region so it remains accessible while scrolling.

When a results list receives focus, render the full list to stabilize keyboard navigation and focus scrolling. Remove the obsolete fixed-grid assertion from the search debug test.

Performance

Synthetic benchmarks with 50 stations and 4× CPU throttling showed lower median initial rendering time:

Viewport	Baseline	Updated
Desktop	15.35 ms	9.69 ms
Mobile	17.88 ms	6.63 ms
Mobile with larger text	19.66 ms	8.34 ms

Rendering work is deferred: cumulative time after scrolling and focusing the list was higher than baseline.

Validation

• 64/64 browser layout and interaction cases passed, plus manual desktop and mobile verification.
• Full suite: 1907 passed, 8 skipped.
• Ruff format/lint, compileall, Mypy, syntax checks for all 45 web JavaScript files, pip check, pip-audit, Bandit and diff checks passed.