Create a single-file interactive atlas for the canonical `/maproom/` route titled "North Atlantic Storm Atlas".

Core brief:
- Subject: North Atlantic storms with shipping lanes between Greenland, Iceland, Atlantic Canada, the British Isles, Iberia, and the Norwegian Sea.
- Tone: maritime operations room meets editorial atlas, with a cold-water palette, luminous storm overlays, and precise cartographic scaffolding.
- Deliverable: one `index.html` with inline HTML, CSS, and vanilla JS only.

Experience requirements:
- Render an authored North Atlantic map viewport with visible coast silhouettes, graticules, wayfinding labels, and scale cues.
- Include at least 3 overlay modes. Use:
  - pressure field / isobars
  - shipping lanes and convoy corridors
  - storm tracks and hazard radii
- Include filters, a persistent legend, annotation callouts, and a location or route detail panel.
- Support keyboard, mouse, and touch navigation with zoom and pan.
- Include one guided narrative route or timeline mode that walks through storm development and lane re-routing.
- Persist overlay preferences and visited locations in `localStorage`.

Content direction:
- Default story direction: North Atlantic storms atlas with shipping lanes.
- Use operational ports and waypoints such as Halifax, St John's, Reykjavik, Nuuk, Dublin, Lisbon, and Tromso.
- Include named storm systems, route advisories, convoy notes, and a risk summary that changes as the narrative step changes.
- Keep the interface useful both for quick scanning and deep reading.

Visual direction:
- Use sans-serif typography only.
- Avoid generic dashboard cards; make it feel like a compact editorial maproom.
- Emphasise depth with layered ocean gradients, restrained glow, route colours that remain legible, and strong contrast for legends and overlays.