LightTab

A minimal, calm, fast new-tab page for Chrome.
Local-first by default · zero tracking · optional cloud sync

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LightTab replaces your new-tab page with a live clock and greeting (Chinese lunar calendar included), one-box search, a grouped icon grid, a full calendar page, an AI prompt launcher and a movie-of-the-day card — all stored in your own browser. The only required API permission is storage; everything online (cloud sync, wallpaper library, weather) is optional and off until you turn it on.

Screenshots

Calendar page month / week / year, lunar labels, holiday feeds	AI launcher one prompt to several targets, verified send	Settings theme, language, icon geometry, widgets

Features

• Clock & greeting — live time, date and a time-of-day greeting, plus the Chinese lunar calendar (sexagenary year, zodiac, leap months, 1900–2100, computed entirely on-device). The clock can sit in the left column or lifted above the search box (phone-launcher style), switches between 24h and 12h (AM/PM · 上午/下午), can show seconds, and offers three face fonts (modern / serif / mono)
• Calendar page — a dedicated second page (top-left button) with month / week / year views, lunar-day labels and Chinese statutory-holiday badges (休/班), plus a countdown line to the next holiday. Ships with one bundled, zero-network 港新马印泰假期 feed (HK/SG/MY/ID/TH public holidays 2026–2028, removable — deleting it is sticky on the device). You can also subscribe to read-only iCalendar feeds (published iCloud / Google / Outlook links) or import .ics files; recurring rules, TZID, ordinal BYDAY and EXDATE are all expanded on-device, and nothing is ever written back to the source calendar
• One-box search — URL shortcuts (bare domains with paths work), 6 search engines, AI chats and a WorkBuddy deep link. Live suggestions from Baidu / Google / Bing (fetched directly; switchable off in Settings). Tab / Shift+Tab cycles engines; a pure arithmetic expression (e.g. 128 × 3.5) shows an inline result row — Enter copies it, no eval(); the last 10 searches stay local and resurface below the box
• AI prompt launcher (press Alt+Shift+A or the side button) — pick a template, type once, and send the same prompt to several targets at once: Doubao, ChatGPT and DeepSeek via a content script that fills and verifies the send (Enter-first submission, button detection as fallback), WorkBuddy via its desktop deep link. The prompt never travels in the URL — it goes through a short-lived nonce channel in extension storage — and a bare ?q= link from any other website can fill but never auto-send. Per-target delivery status is reported back to the launcher, and a target that never answers within 20 s is flagged with the prompt copied to your clipboard
• Icon grid — drag to a tile’s left/right edge (or the adjacent gap) to insert before/after with a position marker, hold over its center in grid mode to group them into an iOS-style folder (2×2 mini-icon tile, inline rename, drag-out to ungroup; folders auto-dissolve below 2 items; children support direct editing, deletion with undo, and drag-to-reorder), custom groups, and a built-in brand-icon library so no favicon is ever fetched from a third party. Tile size and corner radius are adjustable; the ＋ dialog derives the name from the URL you type and can prefill from the current tab (optional tabs permission, requested on click). One-click Chrome bookmark import (optional bookmarks permission, also requested on click)
• Tasks — optional due dates with an explicit date editor, calendar due markers, and undo for deletions or clearing completed tasks.
• Free canvas layout — on wide screens, widgets and the icon grid can be dragged anywhere; cards snap and swap. The movie card's placement (Settings → Widgets) selects the layout engine: Left column integrates it into the grid, Above search switches to the free canvas — live, no reload. A refused drag explains why and offers a one-click fix
• Movie of the day — a daily pick from a curated annual-best list with poster, rating and a short note; works fully offline, with an optional hot list when online
• Wallpapers — bundled gradient/photo wallpapers, custom image upload, and an optional Bing daily wallpaper library with favorites and daily auto-rotate
• Weather (opt-in) — current conditions for a city you pick, shown on the clock line (there is no separate weather card); powered by Open-Meteo (no API key), cached 30 minutes
• Bilingual UI (English / 中文) — one switch in Settings re-renders everything instantly
• JSON backup / restore and optional cloud sync — email sign-in syncs shortcuts, settings, wallpaper and templates over HTTPS; first-login differences and concurrent edits pause the affected document for an explicit choice, and local recovery backups are taken before any replacement

Privacy

• Required API permission: storage only. No tracking, no analytics, no ads
• Everything online is optional and off by default: cloud sync, wallpaper library, weather, calendar subscriptions
• Search suggestions (on by default, switchable) are sent directly to your chosen search engine (Baidu / Google / Bing)
• Calendar feed URLs never leave the device — a published calendar link is an unguessable key, so it stays in local storage, excluded from sync and exports. Feed hosts are requested on demand via a single HTTPS-only optional_host_permissions wildcard; plaintext http:// feeds are rejected
• AI launching happens through the target's own page (content scripts declared for Doubao, Dola, ChatGPT and DeepSeek); auto-send requires a nonce written by the extension itself
• WorkBuddy detection probes 127.0.0.1 ports 18488–18490 on startup to detect the local desktop app

See privacy.html for the full policy.

Sync recovery

In Settings → Sync, expand the device/cloud previews before choosing a conflicting copy. The choice applies to that whole document, not individual items. The latest 3 recovery backups remain on this browser — they include the synced data documents and the schema version, never credentials or search history. Restore to device backs up current content first, then signs out and restores locally.

Install

Chrome Web Store — install the published build from the store listing (updates arrive on their own; see below).

GitHub Release — download lighttab-*-chrome.zip from Releases, unzip, then load it unpacked (below).

Developer mode

1. Clone this repo (or unzip a release build)
2. Open chrome://extensions
3. Enable Developer mode (top right)
4. Click Load unpacked and select the folder

Updating

Chrome only installs extension updates while an extension is idle, and an open extension page counts as "in use" — LightTab is the new-tab page, so js/background.js applies a downloaded update as soon as it is ready instead of waiting for a browser restart. To force a check immediately: chrome://extensions → Developer mode → Update. No need to reinstall — uninstalling clears local data unless cloud sync is on. A copy loaded with Load unpacked is a separate extension: it never auto-updates and does not share storage. Full release runbook: docs/RELEASING.md.

Tech

• Chrome Extension Manifest V3
• Chrome 114+ (minimum_chrome_version in manifest.json): the UI uses color-mix() and the popover attribute, so older builds would render broken layout instead of degrading silently
• Plain HTML / CSS / vanilla JS — zero dependencies, zero build step
• chrome.storage.local with a localStorage fallback (so file:// preview works)
• Schema-versioned migrations
• i18n is a flat local dictionary plus [data-i18n] DOM hooks — no runtime library
• Self-contained iCalendar reader (js/ics.js) — RRULE expansion, real timezone maths via Intl, no library

Testing

Kept out of the runtime (zero runtime dependencies):

1. Offline smoke — node scripts/smoke.cjs: JS syntax, manifest/version consistency, pure-function assertions and static DOM/CSS guards. Runs in CI on every push.

2. Browser E2E — Playwright drives the page in file:// preview mode. Runs in CI, and locally:

   npm install                    # dev-only dependency: playwright
   npx playwright install chromium
   npm run test:e2e               # or: npm run check:all  (smoke + every browser check)

3. Real extension installation — node scripts/check-extension.cjs loads the actual MV3 extension in an isolated profile, blocks external requests, and verifies boot, storage persistence, the sync conflict/backup/restore flow through the real settings UI, and the free-canvas layout. node scripts/check-upgrade.cjs upgrades a real 1.18.0 profile in place and asserts data survives; it needs full git history (git fetch --unshallow) because it builds the old release from an earlier commit. Both run in CI. Run all of them before publishing a release.

4. Sync safety scenarios — node scripts/check-sync.cjs (also run by the smoke suite): first sign-in, two-device conflicts, stale choices, offline reconnect, deletion, malformed payloads and backup quota failures against mocked storage.

Structure

lighttab/
├── manifest.json            # MV3 manifest
├── newtab.html              # entry page (home + calendar page + settings)
├── privacy.html             # privacy policy
├── css/style.css
├── js/
│   ├── app.js               # main logic (storage / clock / search / grid / settings / launcher)
│   ├── canvas.js            # free-canvas layout engine
│   ├── calendar.js          # feed transport: permissions, fetch, cache, re-expansion
│   ├── ics.js               # self-contained iCalendar reader (RRULE / TZID / EXDATE)
│   ├── sync.js              # optional cloud sync (revision CAS, conflicts, recovery backups)
│   ├── background.js        # service worker: update self-apply, context menu, temp sweeper
│   ├── inject-ai.js         # content script: fills and verifies sends on supported AI sites
│   ├── i18n.js              # zh + en dictionary, t() runtime, static DOM pass
│   ├── lunar.js             # Chinese lunar calendar (1900–2100)
│   ├── holidays.js          # China statutory-holiday table (2026, refreshed yearly)
│   ├── icondb.js            # built-in brand-icon library (vector paths + assets/brand-icons refs)
│   └── prompts.js           # AI prompt templates
├── assets/
│   ├── sea-holidays.ics     # bundled HK/SG/MY/ID/TH holidays (scripts/build-sea-holidays.cjs)
│   ├── movies/              # bundled movie posters, loaded per card (scripts/build-movie-posters.cjs)
│   └── brand-icons/         # heavy raster brand marks, loaded on demand (scripts/build-brand-icons.cjs)
├── scripts/                 # smoke / e2e / packaging / ICS generator (node, no deps)
├── tests/e2e/               # local Playwright tests
└── icons/                   # 16 / 48 / 128

License

MIT