## Version 1.3.1
— Fixed AccelerScroll not working on back

## Version 1.3.0 — language packs

Reader controls and native Android dialogs now share bundled JSON strings in
`app/src/main/assets/reader/langpacks/en.json` and `ja.json`. Labels use one
language at a time. Open the reader controls and choose **Language** to switch
immediately; the choice is saved and also applies to native menus and prompts.
The chapter text remains Japanese.

`langpacks/config.json` sets `defaultLanguage` and the `supportedLanguages` map
(language code → display name). The default is English. To add a language, copy
`en.json` to `<code>.json`, translate its values, and register its code and name
in the map. Language codes use letters with optional hyphen-separated subtags.
Keep keys and `{placeholder}` names intact. Translation strings are plain text.
Packs load from bundled extension assets, without remote requests. Missing keys,
unsupported saved selections and failed selected-pack loads use the configured
default pack. The config and default pack must be valid and bundled.

The native app reads the same config and restores its last language at startup;
reader language changes reach it through the existing native message bridge.
Already-open native dialogs use their language at creation time.

Validation (no APK build): `node tests/i18n.test.cjs`,
`node tests/motion.test.cjs`, and `node tests/reader.test.cjs`. Reader tests cover
live language changes, persistence, preserved colors/position and native messages.
The extension version is bumped to ensure GeckoView reloads its bundled assets.

## Version 1.2.0 — paragraph focus

Tap any paragraph, including its ruby text, to apply the focused text color.
Only one paragraph is focused at a time. Enter or Space on a keyboard-focused
paragraph also selects it. Links, swipes and long-press text selection keep
their existing behavior. Tap the focused paragraph again or tap empty space
to toggle controls.

While accelerometer scrolling moves the text outside the braking range, focus
tracks the visible paragraph nearest the screen center, in either direction
and during calibration preview. Inside the braking range, the current focus
stays unchanged, even while residual velocity brakes. Manual scrolling does
not automatically change focus.

**Normal text** and **Focus text** color controls save your choices locally.
Custom colors apply across themes; **Reset text colors** restores the current
theme's defaults. Focus changes only text color and does not shift the layout.

## Version 1.1.1 — live calibration

Calibration shows a live tilt marker on a −1 to +1 g scale, a shaded braking
range, its center, and exact trigger thresholds with reading direction labels.
The stop-range offset slider moves the center; **Set neutral** captures the
current tilt. The offset remains session-only and resets on rotation, as before.
The marker keeps updating while paused, and the status shows actual scroll velocity.

Use **Resume preview** to scroll the chapter while calibration stays open;
**Pause preview** stops immediately. Changes to the sliders take effect during
preview. Collapsing calibration, toggling controls, disabling tilt or leaving
the app cancels preview. Ordinary reading resumes when controls are hidden.

Tuning preferences and the enabled switch persist (default OFF).
Opening a chapter, enabling motion, or rotating captures a fresh neutral angle; calibration
is intentionally session-only so an old grip does not unexpectedly start scrolling.
Touch/selection pauses motion. Closing the reader, losing app focus, backgrounding,
missing sensor samples or navigation stops it. The Android listener has a one-second
watchdog and unregisters when unused. Screen-on is requested only while moving.
No new Android permission is required. Devices without an accelerometer show an
unavailable message; ordinary swipe reading still works.

Implementation: `TiltSensor.java` collects filtered, display-relative samples;
`motion.js` holds the acceleration/braking model; `content.js` owns calibration,
controls, animation, and native polling. Android sensor coordinates follow the
[Android sensor documentation](https://developer.android.com/develop/sensors-and-location/sensors/sensors_overview).

Run `node tests/motion.test.cjs` for physics checks and `node tests/reader.test.cjs`
for Firefox integration checks with a simulated native accelerometer. The latter
covers movement, pausing, reversing, inactive samples, rotation and settings.
Actual sensor feel and device lifecycle still require a phone check.

## Version 1.1.0 — accelerometer scrolling

Ported from your Windows AccelerScroll.cs and ReaderContent.xaml.cs. This uses
sideways accelerometer tilt (including gravity), not gyroscope angular velocity.
The acceleration → capped velocity → neutral-zone braking behavior is retained.
Values now use CSS pixels/second and pixels/second², rather than pixels/timer tick.
The neutral zone is symmetric around the calibrated position, correcting the old
offset-dependent range. The old auto-anchor option is replaced by the reader's
existing saved position, checkpointed every two seconds while motion scrolling.

1. Tap empty space (or the focused paragraph) to show controls. Tap **傾き: OFF** to enable it.
2. Hold the phone at your comfortable reading angle; tap **Set neutral**.
3. Tap **読書に戻る**. Tilt sideways to accelerate, tilt the other way to reverse,
   or return to neutral to brake. Opening controls stops scrolling immediately.
4. Expand **Tilt scrolling** to adjust acceleration, maximum speed, neutral-zone
   width, braking strength, or reverse direction. Controls initially pause scrolling.