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+# AGENTS.md — Guide for AI agents working in this repo
+
+> If you are an AI coding agent landing in this repository, **read this file
+> before doing anything else**. It will save you (and the human) a lot of
+> wasted turns.
+
+---
+
+## 1. What this repo is
+
+`AadhatManagementApp` — a Hindi/English wholesale-retail business app for
+small-scale grain/produce traders. It runs on **Firebase Hosting + Firestore +
+Auth**, is built as **vanilla ES module-style JS** (no bundler, no framework),
+and is wrapped in **Capacitor** for Android distribution.
+
+- **Owner**: `DDancingDeath` (https://github.com/DDancingDeath/AadhatManagementApp)
+- **Live URL**: `https://aadhat-management.web.app`
+- **A read-only staging clone exists** at
+  `https://github.com/DDancingDeath/AadhatManagementApp-staging` (private).
+  All risky improvements are tried there first; verified fixes are
+  cherry-picked / PR'd back here. See section 6.
+
+---
+
+## 2. The unbreakable rules
+
+1. **This repo is production.** Real users in the field are using the live
+   site and the Android build. Treat every change like a security patch:
+   small, reviewed, reversible.
+2. **Never bypass `FirebaseService`.** All Firestore reads/writes must go
+   through the wrapper so collection prefixing (`prod_*` / `staging_*`)
+   stays correct. Several existing modules bypass it — those are bugs, not
+   patterns to copy.
+3. **Don't add a build step or framework.** No webpack, no Vite, no React.
+   Inline `<script>` tags + `window.app` globals are a deliberate choice and
+   the staging clone depends on cherry-pick parity.
+4. **Don't rename existing files casually.** Inline `onclick="window.app.x.y()"`
+   handlers and `template-loader.js` reference paths and method names by
+   exact string.
+5. **Always run `npm install --legacy-peer-deps`.** `canvas@^3.2.0` peer-
+   conflicts with `jest-environment-jsdom`. The dependency itself is unused
+   and slated for removal — until then, the legacy-peer-deps flag is
+   mandatory.
+6. **Money-related changes get extra care.** Bills mix top-level
+   `dueAmount` with nested `payment.due`. Both can drift; both must be
+   read/written. Cash-management adjustments hit balance + audit log; both
+   must succeed atomically.
+7. **No secrets in the repo.** API keys belong in Firebase Functions config
+   (`firebase functions:config:set`), not in any source file.
+
+---
+
+## 3. Where to start reading
+
+In order:
+
+1. `README.md` — original setup / install / deploy instructions.
+2. `firestore.rules` — the authoritative permission model.
+3. `www/index.html` — script load order; this is the SPA shell.
+4. `www/js/main.js` — wires every module onto `window.app.*`.
+5. `www/firebaseConfig.js` — initializes Firebase, exposes `firebase.*`
+   compat globals.
+6. `www/js/firebase/firestore-service.js` — every read/write should go
+   through here.
+
+---
+
+## 4. Codebase orientation (the bits you'll get wrong)
+
+### Naming surprises
+
+| You'd guess | Actual file |
+|---|---|
+| `expenses.js` | `www/js/modules/miscellaneous.js` |
+| `printer.js` (modules) | `www/js/services/printer.js` |
+| `wholesaleSalesHistory` | `AppState.salesHistory` (just "salesHistory" means **wholesale** here) |
+| `retailSalesHistory` | `AppState.retailSalesHistory` (this one's normal) |
+| `chat.js` | does not exist in prod — the AI Assistant tab is wired but not implemented (a real chat module ships from the staging clone) |
+| `bottom-nav.html` | doesn't exist — the "bottom" tabs are the bottom of the side nav in `navigation.html` |
+
+### Conventions
+
+- **All UI updates run inline `onclick` handlers** that call
+  `window.app.*`. To expose a new module method to the UI, register it in
+  `main.js` — never assume `app` (without `window.`) resolves correctly
+  from an inline handler. (`firebaseConfig.js` used to declare
+  `let app = firebase.initializeApp(...)` at module top-level which
+  shadowed `window.app` for inline handlers; the staging clone fixed this
+  by renaming to `firebaseApp`.)
+- **All Firestore access goes through `FirebaseService`** so collection
+  names get the env prefix.
+- **Templates live in `www/templates/`**. They are loaded by
+  `template-loader.js` on demand and inserted into the SPA shell.
+- **Date strings**: bills mix ISO-8601 and `DD/MM/YYYY`. Use
+  `Helpers.parseDate()` — never raw `new Date(string)`.
+- **Money fields**: bills sometimes store `dueAmount` at top level *and*
+  `payment.due` inside a nested object. Both can exist; both can drift.
+  Read both, write both, treat the nested one as canonical when present.
+- **State**: a single `AppState` object lives in `state.js`. Never invent
+  a parallel cache.
+
+### Things that look wrong but aren't
+
+- The `xlsx` global pollution warning in tests is expected (SheetJS).
+- `firebase` global is the compat-SDK style — modular SDK is intentionally
+  not used.
+- Many functions are async but don't await — that's a real bug, but
+  documented; don't "fix" them silently.
+
+---
+
+## 5. Standard workflows
+
+### "I want to fix a bug"
+
+1. Confirm the bug is also tracked in the staging clone's
+   `docs/REVIEW_ISSUES.md` (most known bugs already are). If it isn't,
+   add it there *first* — that file is the running master list.
+2. Make the change in `www/js/...`.
+3. Run `npm install --legacy-peer-deps && npm test`. Baseline must stay
+   green.
+4. Commit with a message like
+   `fix(stock): refresh current-stock pane after adjustment (REVIEW_ISSUES WALK-25)`.
+5. Open a PR. Don't merge to `main` directly — Firebase Hosting auto-deploys
+   on merge to `main`.
+
+### "I want to add a new capability"
+
+1. Strongly consider doing it in the staging clone first. The staging
+   clone is the place for greenfield work; prod is for stabilised fixes.
+2. If it must land directly in prod: update tests, update README if user-
+   facing, ship behind a config flag if behaviour-changing.
+
+### "The CSS / a single template needs a tweak"
+
+These are usually safe to do directly in prod. Use a Playwright probe in
+`tools/` to verify before pushing if the visual impact is non-trivial. The
+staging clone has examples (`tools/_verify-bottom-buttons.js`).
+
+---
+
+## 6. The staging clone
+
+A separate private repo (`AadhatManagementApp-staging`) exists as a
+read-only safety mirror. It:
+
+- Connects to the same Firebase project (`aadhat-management`).
+- Cannot write to Firestore — three layers of write-blocking enforce this:
+  (1) a JS guard that monkey-patches the SDK, (2) a service worker that
+  403s every non-GET request to Firebase hosts, (3) an additive Firestore
+  rule that denies writes from a single dedicated `staging-readonly` user.
+- Hosts at `https://aadhat-staging.web.app`.
+- Is where the AI Assistant is being designed (see staging
+  `docs/CHAT_DESIGN.md`).
+- Is where every behavioural fix is verified before it's PR'd here.
+
+When a fix lands here that originated in staging, the commit message
+should reference the staging commit SHA so the audit trail is preserved.
+
+---
+
+## 7. Firestore rules — reminder
+
+`firestore.rules` in this repo is the source of truth for Firebase's
+deployed rules. **Editing these without updating Rules Playground tests
+can break every user immediately**. Always:
+
+1. Edit the file.
+2. Run `firebase emulators:start --only firestore` and exercise the
+   Playground for: owner-creates-bill, staff-creates-bill,
+   staging-readonly-blocked.
+3. Only then `firebase deploy --only firestore:rules`.
+
+---
+
+## 8. Common pitfalls
+
+- **`firebase.firestore()` calls outside `FirebaseService`** — bypass the
+  collection-prefix wrapper. Will write to the wrong collection in
+  staging. Always use `FirebaseService.getCollection(name)` instead.
+- **`new Date(billDate)` where `billDate` is `DD/MM/YYYY`** — JS parses
+  this as `MM/DD/YYYY` on most browsers and silently produces a wrong
+  date. Use `Helpers.parseDate()`.
+- **`alert(`...${userInput}...`)` and `innerHTML = ...userInput...`** —
+  XSS. Use `Helpers.escapeHtml()` on every concatenated user value before
+  it touches the DOM.
+- **Non-batched per-recipient `for await { add() }` loops** — slow and
+  partial-failure-prone. Use a `WriteBatch`.
+- **Bill numbering with `count + 1`** — race condition. Use a Firestore
+  transaction on a daily counter document.
+
+---
+
+## 9. When in doubt
+
+Stop and ask. The cost of a wrong production change is paid by the owner
+in customer-facing breakage; the cost of one extra clarifying question is
+zero.
diff --git a/www/css/tabs.css b/www/css/tabs.css
index ccea5ea..5064331 100644
--- a/www/css/tabs.css
+++ b/www/css/tabs.css
@@ -1,6 +1,15 @@
 .tab {
   display: none;
-  padding: 70px 16px 24px 16px;
+  /* Bottom padding raised from 24px → calc(96px + safe-area) so the
+     last row of action buttons (WhatsApp / Save / Print on Bills, etc.)
+     is not clipped by the Windows taskbar, by mobile browser dynamic
+     chrome, or by the iOS home-indicator safe area. The 96px alone
+     covers desktop OS taskbars; env(safe-area-inset-bottom) adds the
+     iOS notch/home-bar inset on top. height: 100vh is intentionally
+     kept — replacing it is a larger refactor with risk of breaking
+     inner-scroll on Android. See REVIEW_ISSUES STG-WALK-6 in the
+     staging clone for full context. */
+  padding: 70px 16px calc(96px + env(safe-area-inset-bottom, 0px)) 16px;
   max-width: 480px;
   min-height: 100vh;
   height: 100vh;