What to try — b9-car-book

# WHAT TO TRY — B9 Car Book ("Car Book Binder Red")

Open `index.html` in any modern browser (double-click the file, or serve the folder). No install, no account — the page makes no network calls.

1. **Read the posture line first.** At the top: "Your records, on your device" — export is the printable sheet or a JSON download. If that isn't obvious in 10 seconds, the page failed its main job.
2. **Look at the SAMPLE book.** The car switcher shows "Sample Sedan — SAMPLE BOOK — 2020 (sample)". Its 5 entries (brake pads, an oil change, a belt, a winter-check note, a cabin filter) are all invented and stamped **SAMPLE**. Check the totals line: total $323.74 — Part $114.24 · Service $64.50 · Repair $145.00 · Note $0.00 — and the last-service line naming the oil change.
3. **Open the BUILD SHEET.** Tap **BUILD SHEET**: a clean sheet should open (and also download as `car-book-build-sheet.html`). Check the header carries the car exactly as named, the parts list holds only the two Part entries with costs, the service history holds the Service and Repair entries, and the totals at the bottom match step 2. Print preview it — it should read as one tidy sheet.
4. **Export the JSON.** Tap **EXPORT JSON** and open `car-book-export.json`: the car and every entry are in there, in date order, in plain readable JSON. That file is the book's survival copy.
5. **Start your own book — empty.** Tap **"Start an empty book."** The sample disappears and does not come back on reload. Add a car with the name/year fields (free-text — type whatever you call the car), then add a first real entry: date, kind, title, cost, mileage. It should appear in date order and move the totals.
6. **Try the optional fields.** On one entry, attach a photo (it previews and lands in the entry) and type a log link or a file label (e.g. the name of a log file you keep elsewhere). Both are stored with the entry; the link is text only — nothing is fetched.
7. **Switch cars.** Add a second car, put an entry in each book, and switch back and forth: totals, last-service, and entries must stay with their own car.
8. **Reload the page.** Every book, entry, and total is still there — that's localStorage, on this device only.

The real test this prototype is staging for: migrate one real car's scattered notebook / spreadsheet / forum-post record into a book, timed, and ask whether the printed build sheet — not the app — is the thing that belongs in the car's folder. That run is a separate commission, with the owner's own figures entered by him.