▸ Duration recalculates automatically when you change dates. ▸ Year auto-fills from the start date. ▸ Missing coordinates are auto-geocoded from a built-in city gazetteer; unknown cities can be given coordinates manually. ▸ "Save & Regenerate" rebuilds every map, chart, ranking and metric live — no refresh. Add 2027+ and new year tabs appear automatically. ▸ Edits persist in this browser via local storage.