diff --git a/src/lib/components/Header.svelte b/src/lib/components/Header.svelte
index 74bb47b..a40ec2c 100644
--- a/src/lib/components/Header.svelte
+++ b/src/lib/components/Header.svelte
@@ -15,6 +15,7 @@
   <nav class="nav">
     <a href="/">{$t('nav.dashboard')}</a>
     <a href="/parts">{$t('nav.parts')}</a>
+    <a href="/invoices/new">{$t('nav.new_sale')}</a>
     <a href="/movements/new">{$t('nav.movements')}</a>
     <a href="/suppliers">{$t('nav.suppliers')}</a>
     <a href="/admin">{$t('nav.admin')}</a>
diff --git a/src/lib/i18n/en.json b/src/lib/i18n/en.json
index 1be4c1e..c7ad5eb 100644
--- a/src/lib/i18n/en.json
+++ b/src/lib/i18n/en.json
@@ -6,6 +6,7 @@
   "nav": {
     "dashboard": "Dashboard",
     "parts": "Parts",
+    "new_sale": "New sale",
     "movements": "Movements",
     "suppliers": "Suppliers",
     "admin": "Backups",
@@ -119,6 +120,37 @@
       "restore_failed": "Restore failed. See the server logs."
     }
   },
+  "invoices": {
+    "title": "New sale",
+    "saved_title": "Invoice",
+    "add_part": "Add a part",
+    "add_custom": "Add custom line",
+    "custom_label": "Description",
+    "custom_placeholder": "e.g. Labor, delivery, discount",
+    "item": "Item",
+    "no_inventory_impact": "Custom line — no inventory change",
+    "lines": "Lines on this invoice",
+    "no_lines": "No lines yet — add a part or a custom line to get started.",
+    "line_total": "Line total",
+    "running_total": "Running total",
+    "save": "Save Invoice",
+    "cancel": "Cancel invoice",
+    "cancel_confirm": "Permanently discard this draft? All added lines will be lost.",
+    "saved_total": "Total",
+    "saved_thanks": "Scan the QR code below to pay.",
+    "new_another": "Start a new sale",
+    "errors": {
+      "part_required": "Pick a part.",
+      "quantity_required": "Quantity must be a positive whole number.",
+      "label_required": "Description is required for custom lines.",
+      "not_enough_stock": "One or more lines exceed available stock. Adjust quantities and try again.",
+      "empty": "Add at least one line before saving.",
+      "save_failed": "Could not save the invoice. Please try again.",
+      "add_failed": "Could not add this line.",
+      "update_failed": "Could not update this line.",
+      "line_missing": "Line not found."
+    }
+  },
   "suppliers": {
     "title": "Suppliers",
     "name": "Name",
diff --git a/src/lib/i18n/tg.json b/src/lib/i18n/tg.json
index 6952934..861fdb7 100644
--- a/src/lib/i18n/tg.json
+++ b/src/lib/i18n/tg.json
@@ -6,6 +6,7 @@
   "nav": {
     "dashboard": "Лавҳаи асосӣ",
     "parts": "Қисмҳо",
+    "new_sale": "Фурӯши нав",
     "movements": "Ҳаракатҳо",
     "suppliers": "Таъминкунандагон",
     "admin": "Нусхаҳо",
@@ -119,6 +120,37 @@
       "restore_failed": "Барқарорсозӣ ноком шуд. Логи серверро бинед."
     }
   },
+  "invoices": {
+    "title": "Фурӯши нав",
+    "saved_title": "Фактура",
+    "add_part": "Илова кардани қисм",
+    "add_custom": "Илова кардани сатри иловагӣ",
+    "custom_label": "Тавсиф",
+    "custom_placeholder": "масалан: кор, расондан, тахфиф",
+    "item": "Маҳсулот",
+    "no_inventory_impact": "Сатри иловагӣ — ба захира таъсир намерасонад",
+    "lines": "Сатрҳои ин фактура",
+    "no_lines": "Ҳоло ягон сатр нест — як қисм ё сатри иловагӣ илова кунед.",
+    "line_total": "Маблағи сатр",
+    "running_total": "Ҳамагӣ ҷорӣ",
+    "save": "Захира кардани фактура",
+    "cancel": "Бекор кардани фактура",
+    "cancel_confirm": "Ин лоиҳаро пурра нест мекунед? Ҳамаи сатрҳои иловашуда гум мешаванд.",
+    "saved_total": "Ҳамагӣ",
+    "saved_thanks": "Барои пардохт рамзи QR-ро аз поён скан кунед.",
+    "new_another": "Фурӯши нав сар кардан",
+    "errors": {
+      "part_required": "Қисмро интихоб кунед.",
+      "quantity_required": "Миқдор бояд бутун ва мусбат бошад.",
+      "label_required": "Барои сатри иловагӣ тавсиф зарур аст.",
+      "not_enough_stock": "Як ё якчанд сатр аз захираи мавҷуда зиёд аст. Миқдорро тағйир дода, аз нав кӯшиш кунед.",
+      "empty": "Пеш аз захира кардан камаш як сатр илова кунед.",
+      "save_failed": "Захира кардани фактура муяссар нашуд. Аз нав кӯшиш кунед.",
+      "add_failed": "Илова кардани ин сатр муяссар нашуд.",
+      "update_failed": "Тағйир додани ин сатр муяссар нашуд.",
+      "line_missing": "Сатр ёфт нашуд."
+    }
+  },
   "suppliers": {
     "title": "Таъминкунандагон",
     "name": "Ном",
diff --git a/src/lib/server/invoices.js b/src/lib/server/invoices.js
new file mode 100644
index 0000000..de05db1
--- /dev/null
+++ b/src/lib/server/invoices.js
@@ -0,0 +1,194 @@
+import { getDb } from './db.js';
+import { recordMovement } from './movements.js';
+
+export function getPendingInvoice() {
+  const db = getDb();
+  const invoice = db.prepare(`
+    SELECT * FROM invoices WHERE status = 'pending' LIMIT 1
+  `).get();
+  if (!invoice) return null;
+  return { invoice, lines: linesFor(invoice.id) };
+}
+
+export function getOrCreatePendingInvoice() {
+  const db = getDb();
+  const existing = db.prepare(`SELECT * FROM invoices WHERE status = 'pending' LIMIT 1`).get();
+  if (existing) return { invoice: existing, lines: linesFor(existing.id) };
+  const id = db.prepare(`INSERT INTO invoices (status) VALUES ('pending')`).run().lastInsertRowid;
+  const invoice = db.prepare(`SELECT * FROM invoices WHERE id = ?`).get(id);
+  return { invoice, lines: [] };
+}
+
+export function getInvoice(id) {
+  const db = getDb();
+  const invoice = db.prepare(`SELECT * FROM invoices WHERE id = ?`).get(Number(id));
+  if (!invoice) return null;
+  return { invoice, lines: linesFor(invoice.id) };
+}
+
+function linesFor(invoiceId) {
+  return getDb().prepare(`
+    SELECT
+      l.*,
+      p.sku        AS part_sku,
+      p.name_en    AS part_name_en,
+      p.name_tg    AS part_name_tg,
+      p.quantity_on_hand AS part_on_hand
+    FROM invoice_lines l
+    LEFT JOIN parts p ON p.id = l.part_id
+    WHERE l.invoice_id = ?
+    ORDER BY l.sort_order, l.id
+  `).all(invoiceId);
+}
+
+function nextSortOrder(invoiceId) {
+  const row = getDb().prepare(`
+    SELECT COALESCE(MAX(sort_order), 0) + 1 AS n FROM invoice_lines WHERE invoice_id = ?
+  `).get(invoiceId);
+  return row.n;
+}
+
+/**
+ * Add a parts-based line to an invoice. If a line for the same part_id
+ * already exists on this invoice, increments that line's quantity rather
+ * than inserting a new row (per-edit merge). The line's unit price is left
+ * alone in the merge case so a user-edited price isn't clobbered.
+ */
+export function addLine({ invoice_id, part_id, quantity, unit_price_dirams }) {
+  const db = getDb();
+  const invoiceId = Number(invoice_id);
+  const partId    = Number(part_id);
+  const qty       = Math.floor(Number(quantity));
+  if (!invoiceId) throw new Error('invoice_id required');
+  if (!partId)    throw new Error('part_id required');
+  if (!Number.isInteger(qty) || qty <= 0) throw new Error('quantity must be a positive integer');
+
+  return db.transaction(() => {
+    const part = db.prepare(`SELECT id, sale_price FROM parts WHERE id = ?`).get(partId);
+    if (!part) throw new Error(`part ${partId} not found`);
+
+    const price = (unit_price_dirams === '' || unit_price_dirams == null)
+      ? Number(part.sale_price || 0)
+      : Math.round(Number(unit_price_dirams));
+
+    const existing = db.prepare(`
+      SELECT id, quantity FROM invoice_lines
+      WHERE invoice_id = ? AND part_id = ? AND affects_inventory = 1
+      LIMIT 1
+    `).get(invoiceId, partId);
+
+    if (existing) {
+      db.prepare(`UPDATE invoice_lines SET quantity = ? WHERE id = ?`)
+        .run(existing.quantity + qty, existing.id);
+      return existing.id;
+    }
+
+    return db.prepare(`
+      INSERT INTO invoice_lines
+        (invoice_id, part_id, label, quantity, unit_price_dirams, affects_inventory, sort_order)
+      VALUES (?, ?, NULL, ?, ?, 1, ?)
+    `).run(invoiceId, partId, qty, price, nextSortOrder(invoiceId)).lastInsertRowid;
+  })();
+}
+
+export function addCustomLine({ invoice_id, label, quantity, unit_price_dirams }) {
+  const db = getDb();
+  const invoiceId = Number(invoice_id);
+  const cleanLabel = (label || '').trim();
+  const qty   = Math.floor(Number(quantity));
+  const price = Math.round(Number(unit_price_dirams || 0));
+  if (!invoiceId)  throw new Error('invoice_id required');
+  if (!cleanLabel) throw new Error('label required');
+  if (!Number.isInteger(qty) || qty <= 0) throw new Error('quantity must be a positive integer');
+
+  return db.prepare(`
+    INSERT INTO invoice_lines
+      (invoice_id, part_id, label, quantity, unit_price_dirams, affects_inventory, sort_order)
+    VALUES (?, NULL, ?, ?, ?, 0, ?)
+  `).run(invoiceId, cleanLabel, qty, price, nextSortOrder(invoiceId)).lastInsertRowid;
+}
+
+export function updateLine(line_id, { quantity, unit_price_dirams, label }) {
+  const db = getDb();
+  const id  = Number(line_id);
+  if (!id) throw new Error('line_id required');
+
+  const current = db.prepare(`SELECT * FROM invoice_lines WHERE id = ?`).get(id);
+  if (!current) throw new Error(`line ${id} not found`);
+
+  const qty   = quantity == null || quantity === ''
+    ? current.quantity
+    : Math.floor(Number(quantity));
+  if (!Number.isInteger(qty) || qty <= 0) throw new Error('quantity must be a positive integer');
+
+  const price = unit_price_dirams == null || unit_price_dirams === ''
+    ? current.unit_price_dirams
+    : Math.round(Number(unit_price_dirams));
+
+  const newLabel = current.affects_inventory === 0
+    ? (label == null ? current.label : String(label).trim() || current.label)
+    : current.label;
+
+  db.prepare(`
+    UPDATE invoice_lines SET quantity = ?, unit_price_dirams = ?, label = ?
+    WHERE id = ?
+  `).run(qty, price, newLabel, id);
+}
+
+export function removeLine(line_id) {
+  getDb().prepare(`DELETE FROM invoice_lines WHERE id = ?`).run(Number(line_id));
+}
+
+/**
+ * Commit the invoice: for each inventoried line, record an 'out' stock
+ * movement (which decrements parts.quantity_on_hand atomically and rejects
+ * if there's not enough stock). All movements + the status flip happen in
+ * one transaction — if any line fails, nothing is decremented and the
+ * draft stays pending.
+ */
+export function saveInvoice(invoice_id) {
+  const db = getDb();
+  const id = Number(invoice_id);
+
+  return db.transaction(() => {
+    const invoice = db.prepare(`SELECT * FROM invoices WHERE id = ?`).get(id);
+    if (!invoice) throw new Error(`invoice ${id} not found`);
+    if (invoice.status !== 'pending') throw new Error('invoice already saved');
+
+    const lines = db.prepare(`
+      SELECT * FROM invoice_lines WHERE invoice_id = ? ORDER BY sort_order, id
+    `).all(id);
+    if (lines.length === 0) throw new Error('cannot save empty invoice');
+
+    const reference = `INV-${id}`;
+    for (const line of lines) {
+      if (line.affects_inventory !== 1) continue;
+      recordMovement({
+        part_id: line.part_id,
+        movement_type: 'out',
+        quantity: line.quantity,
+        unit_price: line.unit_price_dirams / 100,
+        reference
+      });
+    }
+
+    const total = lines.reduce(
+      (sum, l) => sum + (l.quantity * l.unit_price_dirams),
+      0
+    );
+
+    db.prepare(`
+      UPDATE invoices
+      SET status = 'saved', saved_at = datetime('now'), total_dirams = ?
+      WHERE id = ?
+    `).run(total, id);
+
+    return id;
+  })();
+}
+
+export function cancelInvoice(invoice_id) {
+  getDb().prepare(`
+    DELETE FROM invoices WHERE id = ? AND status = 'pending'
+  `).run(Number(invoice_id));
+}
diff --git a/src/lib/server/schema.sql b/src/lib/server/schema.sql
index 9ab50df..0f419fa 100644
--- a/src/lib/server/schema.sql
+++ b/src/lib/server/schema.sql
@@ -54,3 +54,28 @@ CREATE INDEX IF NOT EXISTS idx_parts_barcode       ON parts(barcode);
 CREATE INDEX IF NOT EXISTS idx_parts_category      ON parts(category_id);
 CREATE INDEX IF NOT EXISTS idx_movements_part      ON stock_movements(part_id);
 CREATE INDEX IF NOT EXISTS idx_movements_created   ON stock_movements(created_at);
+
+CREATE TABLE IF NOT EXISTS invoices (
+  id           INTEGER PRIMARY KEY AUTOINCREMENT,
+  status       TEXT NOT NULL CHECK(status IN ('pending','saved')) DEFAULT 'pending',
+  total_dirams INTEGER NOT NULL DEFAULT 0,
+  notes        TEXT,
+  created_at   TEXT NOT NULL DEFAULT (datetime('now')),
+  saved_at     TEXT
+);
+
+CREATE TABLE IF NOT EXISTS invoice_lines (
+  id                 INTEGER PRIMARY KEY AUTOINCREMENT,
+  invoice_id         INTEGER NOT NULL REFERENCES invoices(id) ON DELETE CASCADE,
+  part_id            INTEGER REFERENCES parts(id) ON DELETE SET NULL,
+  label              TEXT,
+  quantity           INTEGER NOT NULL CHECK(quantity > 0),
+  unit_price_dirams  INTEGER NOT NULL DEFAULT 0,
+  affects_inventory  INTEGER NOT NULL DEFAULT 1,
+  sort_order         INTEGER NOT NULL DEFAULT 0,
+  created_at         TEXT NOT NULL DEFAULT (datetime('now'))
+);
+
+CREATE INDEX IF NOT EXISTS idx_invoice_lines_invoice ON invoice_lines(invoice_id);
+CREATE UNIQUE INDEX IF NOT EXISTS idx_invoices_one_pending
+  ON invoices(status) WHERE status = 'pending';
diff --git a/src/routes/invoices/[id]/+page.server.js b/src/routes/invoices/[id]/+page.server.js
new file mode 100644
index 0000000..961e4bd
--- /dev/null
+++ b/src/routes/invoices/[id]/+page.server.js
@@ -0,0 +1,10 @@
+import { error } from '@sveltejs/kit';
+import { getInvoice } from '$lib/server/invoices.js';
+
+export function load({ params }) {
+  const result = getInvoice(params.id);
+  if (!result || result.invoice.status !== 'saved') {
+    throw error(404, 'Invoice not found');
+  }
+  return result;
+}
diff --git a/src/routes/invoices/[id]/+page.svelte b/src/routes/invoices/[id]/+page.svelte
new file mode 100644
index 0000000..f9cee36
--- /dev/null
+++ b/src/routes/invoices/[id]/+page.svelte
@@ -0,0 +1,100 @@
+<script>
+  import { locale, t, localized, formatMoney } from '$lib/i18n/store.js';
+
+  export let data;
+  $: lang = $locale;
+  $: ({ invoice, lines } = data);
+
+  function lineLabel(line) {
+    if (line.affects_inventory === 0) return line.label;
+    return `${line.part_sku} — ${localized({ name_en: line.part_name_en, name_tg: line.part_name_tg }, 'name', lang)}`;
+  }
+</script>
+
+<article class="receipt">
+  <header class="head">
+    <div>
+      <h1>{$t('invoices.saved_title')} #{invoice.id}</h1>
+      <p class="muted">{invoice.saved_at}</p>
+    </div>
+    <a href="/invoices/new" class="print-hide back">← {$t('invoices.new_another')}</a>
+  </header>
+
+  <table>
+    <thead>
+      <tr>
+        <th>{$t('invoices.item')}</th>
+        <th class="num">{$t('movements.quantity')}</th>
+        <th class="num">{$t('movements.unit_price')}</th>
+        <th class="num">{$t('invoices.line_total')}</th>
+      </tr>
+    </thead>
+    <tbody>
+      {#each lines as line}
+        {@const lineTotal = line.quantity * line.unit_price_dirams}
+        <tr>
+          <td>{lineLabel(line)}</td>
+          <td class="num">{line.quantity}</td>
+          <td class="num">{formatMoney(line.unit_price_dirams, lang)}</td>
+          <td class="num">{formatMoney(lineTotal, lang)}</td>
+        </tr>
+      {/each}
+    </tbody>
+    <tfoot>
+      <tr>
+        <td colspan="3" class="num"><strong>{$t('invoices.saved_total')}</strong></td>
+        <td class="num">
+          <strong>{formatMoney(invoice.total_dirams, lang)} {$t('common.currency_short')}</strong>
+        </td>
+      </tr>
+    </tfoot>
+  </table>
+
+  <section class="pay">
+    <p class="muted">{$t('invoices.saved_thanks')}</p>
+    <img src="/payment-qr.jpg" alt="Payment QR code" class="qr" />
+  </section>
+</article>
+
+<style>
+  .receipt { max-width: 720px; margin: 0 auto; }
+  .head {
+    display: flex;
+    align-items: flex-start;
+    justify-content: space-between;
+    gap: 1rem;
+    margin-bottom: 1rem;
+  }
+  .head h1 { margin: 0; }
+  .head .muted { margin: 0.25rem 0 0; font-size: 0.9rem; }
+  .back {
+    text-decoration: none;
+    padding: 0.4rem 0.8rem;
+    border: 1px solid #c8cfdc;
+    border-radius: 4px;
+    background: #fff;
+    font-size: 0.9rem;
+  }
+  tfoot td { background: #f5f7fb; }
+  .pay {
+    margin-top: 1.5rem;
+    text-align: center;
+  }
+  .qr {
+    display: block;
+    margin: 0.75rem auto 0;
+    max-width: 280px;
+    width: 100%;
+    height: auto;
+    border: 1px solid #e5e8ee;
+    background: #fff;
+    padding: 6px;
+  }
+
+  @media print {
+    :global(.header), :global(.lang) { display: none !important; }
+    .print-hide { display: none !important; }
+    :global(body) { background: #fff; }
+    :global(.container) { padding: 0; max-width: 100%; }
+  }
+</style>
diff --git a/src/routes/invoices/new/+page.server.js b/src/routes/invoices/new/+page.server.js
new file mode 100644
index 0000000..25e35d2
--- /dev/null
+++ b/src/routes/invoices/new/+page.server.js
@@ -0,0 +1,121 @@
+import { fail, redirect } from '@sveltejs/kit';
+import { listParts } from '$lib/server/parts.js';
+import {
+  getOrCreatePendingInvoice,
+  addLine,
+  addCustomLine,
+  updateLine,
+  removeLine,
+  saveInvoice,
+  cancelInvoice
+} from '$lib/server/invoices.js';
+
+export function load() {
+  const { invoice, lines } = getOrCreatePendingInvoice();
+  return {
+    invoice,
+    lines,
+    parts: listParts()
+  };
+}
+
+function toDirams(value) {
+  if (value === '' || value == null) return 0;
+  const num = typeof value === 'number' ? value : Number(String(value).replace(',', '.'));
+  if (!Number.isFinite(num)) return 0;
+  return Math.round(num * 100);
+}
+
+export const actions = {
+  add_part_line: async ({ request }) => {
+    const data = Object.fromEntries(await request.formData());
+    const errors = {};
+    if (!data.part_id)    errors.add_part = 'invoices.errors.part_required';
+    const qty = Number(data.quantity);
+    if (!Number.isInteger(qty) || qty <= 0) errors.add_part = 'invoices.errors.quantity_required';
+    if (Object.keys(errors).length) return fail(400, { errors, values: data });
+
+    const { invoice } = getOrCreatePendingInvoice();
+    try {
+      addLine({
+        invoice_id: invoice.id,
+        part_id: data.part_id,
+        quantity: qty,
+        unit_price_dirams: data.unit_price === '' || data.unit_price == null ? null : toDirams(data.unit_price)
+      });
+    } catch (err) {
+      return fail(400, { errors: { add_part: 'invoices.errors.add_failed' }, values: data, errMsg: String(err.message) });
+    }
+    return { ok: true };
+  },
+
+  add_custom_line: async ({ request }) => {
+    const data = Object.fromEntries(await request.formData());
+    const errors = {};
+    const label = (data.label || '').trim();
+    const qty   = Number(data.quantity);
+    if (!label) errors.add_custom = 'invoices.errors.label_required';
+    if (!Number.isInteger(qty) || qty <= 0) errors.add_custom = 'invoices.errors.quantity_required';
+    if (Object.keys(errors).length) return fail(400, { errors, values: data });
+
+    const { invoice } = getOrCreatePendingInvoice();
+    addCustomLine({
+      invoice_id: invoice.id,
+      label,
+      quantity: qty,
+      unit_price_dirams: toDirams(data.unit_price)
+    });
+    return { ok: true };
+  },
+
+  update_line: async ({ request }) => {
+    const data = Object.fromEntries(await request.formData());
+    const id  = Number(data.line_id);
+    const qty = Number(data.quantity);
+    if (!id) return fail(400, { errors: { line: 'invoices.errors.line_missing' } });
+    if (!Number.isInteger(qty) || qty <= 0) {
+      return fail(400, { errors: { [`line_${id}`]: 'invoices.errors.quantity_required' } });
+    }
+    try {
+      updateLine(id, {
+        quantity: qty,
+        unit_price_dirams: data.unit_price === '' || data.unit_price == null ? null : toDirams(data.unit_price),
+        label: data.label
+      });
+    } catch (err) {
+      return fail(400, { errors: { [`line_${id}`]: 'invoices.errors.update_failed' }, errMsg: String(err.message) });
+    }
+    return { ok: true };
+  },
+
+  remove_line: async ({ request }) => {
+    const data = Object.fromEntries(await request.formData());
+    const id = Number(data.line_id);
+    if (id) removeLine(id);
+    return { ok: true };
+  },
+
+  save_invoice: async () => {
+    const { invoice, lines } = getOrCreatePendingInvoice();
+    if (lines.length === 0) {
+      return fail(400, { errors: { save: 'invoices.errors.empty' } });
+    }
+    let savedId;
+    try {
+      savedId = saveInvoice(invoice.id);
+    } catch (err) {
+      const msg = String(err.message);
+      if (msg.includes('not enough stock')) {
+        return fail(400, { errors: { save: 'invoices.errors.not_enough_stock' }, errMsg: msg });
+      }
+      return fail(400, { errors: { save: 'invoices.errors.save_failed' }, errMsg: msg });
+    }
+    throw redirect(303, `/invoices/${savedId}`);
+  },
+
+  cancel_invoice: async () => {
+    const { invoice } = getOrCreatePendingInvoice();
+    cancelInvoice(invoice.id);
+    throw redirect(303, '/invoices/new');
+  }
+};
diff --git a/src/routes/invoices/new/+page.svelte b/src/routes/invoices/new/+page.svelte
new file mode 100644
index 0000000..2c57c65
--- /dev/null
+++ b/src/routes/invoices/new/+page.svelte
@@ -0,0 +1,294 @@
+<script>
+  import { enhance } from '$app/forms';
+  import { locale, t, localized, formatMoney } from '$lib/i18n/store.js';
+
+  export let data;
+  export let form;
+  $: lang = $locale;
+  $: ({ invoice, lines, parts } = data);
+
+  $: errors = form?.errors ?? {};
+
+  // Add-a-part section state
+  let partSearch = '';
+  let partId     = '';
+  let partQty    = '1';
+  let partPrice  = '';
+
+  $: filteredParts = (() => {
+    const q = partSearch.trim().toLowerCase();
+    if (!q) return parts;
+    return parts.filter((p) =>
+      (p.sku || '').toLowerCase().includes(q) ||
+      (p.name_en || '').toLowerCase().includes(q) ||
+      (p.name_tg || '').toLowerCase().includes(q) ||
+      (p.barcode || '').toLowerCase().includes(q)
+    );
+  })();
+
+  $: selectedPart = parts?.find((p) => String(p.id) === String(partId));
+  $: visibleParts =
+    selectedPart && !filteredParts.some((p) => p.id === selectedPart.id)
+      ? [selectedPart, ...filteredParts]
+      : filteredParts;
+
+  // Auto-fill the unit-price input from the selected part's sale price,
+  // unless the user has typed something different.
+  let lastAutoPrice = '';
+  $: {
+    if (selectedPart) {
+      const expected = selectedPart.sale_price
+        ? (selectedPart.sale_price / 100).toFixed(2)
+        : '';
+      if (expected && (partPrice === '' || partPrice === lastAutoPrice)) {
+        partPrice = expected;
+        lastAutoPrice = expected;
+      }
+    }
+  }
+
+  // Add-custom-line state
+  let customLabel = '';
+  let customQty   = '1';
+  let customPrice = '';
+
+  $: runningTotalDirams = lines.reduce(
+    (sum, l) => sum + (l.quantity * l.unit_price_dirams),
+    0
+  );
+
+  function lineLabel(line) {
+    if (line.affects_inventory === 0) return line.label;
+    return `${line.part_sku} — ${localized({ name_en: line.part_name_en, name_tg: line.part_name_tg }, 'name', lang)}`;
+  }
+
+  function confirmCancel(event) {
+    if (!confirm($t('invoices.cancel_confirm'))) event.preventDefault();
+  }
+</script>
+
+<h1 class="title">{$t('invoices.title')} <span class="muted">#{invoice.id}</span></h1>
+
+{#if form?.errMsg}
+  <div class="error">{form.errMsg}</div>
+{/if}
+
+<div class="builder">
+  <div class="col left">
+    <section class="card">
+      <h2>{$t('invoices.add_part')}</h2>
+      <form method="POST" action="?/add_part_line" class="stack" use:enhance>
+        <label>
+          {$t('movements.part')} *
+          <input class="part-search"
+                 type="search"
+                 bind:value={partSearch}
+                 placeholder={$t('parts.search_placeholder')} />
+          <select name="part_id" bind:value={partId} required size={Math.min(6, Math.max(3, visibleParts.length + 1))}>
+            <option value="">—</option>
+            {#each visibleParts as p}
+              <option value={String(p.id)}>
+                {p.sku} — {localized(p, 'name', lang)} ({$t('parts.quantity_on_hand')}: {p.quantity_on_hand})
+              </option>
+            {/each}
+          </select>
+          {#if partSearch && filteredParts.length === 0}
+            <small class="muted">{$t('parts.no_results')}</small>
+          {/if}
+        </label>
+
+        <div class="row">
+          <label>
+            {$t('movements.quantity')} *
+            <input name="quantity" type="number" min="1" step="1" required bind:value={partQty} />
+          </label>
+          <label>
+            {$t('movements.unit_price')} ({$t('common.currency_short')})
+            <input name="unit_price" type="number" step="0.01" min="0" bind:value={partPrice} />
+          </label>
+        </div>
+
+        {#if errors.add_part}
+          <span class="field-error">{$t(errors.add_part)}</span>
+        {/if}
+        <div class="actions">
+          <button type="submit">{$t('common.add')}</button>
+        </div>
+      </form>
+    </section>
+
+    <section class="card">
+      <h2>{$t('invoices.add_custom')}</h2>
+      <form method="POST" action="?/add_custom_line" class="stack" use:enhance>
+        <label>
+          {$t('invoices.custom_label')} *
+          <input name="label" type="text" required bind:value={customLabel}
+                 placeholder={$t('invoices.custom_placeholder')} />
+        </label>
+        <div class="row">
+          <label>
+            {$t('movements.quantity')} *
+            <input name="quantity" type="number" min="1" step="1" required bind:value={customQty} />
+          </label>
+          <label>
+            {$t('movements.unit_price')} ({$t('common.currency_short')})
+            <input name="unit_price" type="number" step="0.01" min="0" bind:value={customPrice} />
+          </label>
+        </div>
+        {#if errors.add_custom}
+          <span class="field-error">{$t(errors.add_custom)}</span>
+        {/if}
+        <div class="actions">
+          <button type="submit" class="secondary">{$t('common.add')}</button>
+        </div>
+      </form>
+    </section>
+
+  </div>
+
+  <aside class="col right">
+    <div class="running">
+      <span class="muted">{$t('invoices.running_total')}</span>
+      <strong class="total">{formatMoney(runningTotalDirams, lang)} {$t('common.currency_short')}</strong>
+    </div>
+
+    <section class="lines">
+      <h2>{$t('invoices.lines')}</h2>
+      {#if lines.length === 0}
+        <p class="muted">{$t('invoices.no_lines')}</p>
+      {:else}
+        <table>
+          <thead>
+            <tr>
+              <th>{$t('invoices.item')}</th>
+              <th class="num">{$t('movements.quantity')}</th>
+              <th class="num">{$t('movements.unit_price')}</th>
+              <th class="num">{$t('invoices.line_total')}</th>
+              <th></th>
+            </tr>
+          </thead>
+          <tbody>
+            {#each lines as line (line.id)}
+              {@const lineTotal = line.quantity * line.unit_price_dirams}
+              <tr>
+                <td>
+                  <div>{lineLabel(line)}</div>
+                  {#if line.affects_inventory === 0}
+                    <small class="muted">{$t('invoices.no_inventory_impact')}</small>
+                  {/if}
+                </td>
+                <td class="num">
+                  <form method="POST" action="?/update_line" class="inline" use:enhance>
+                    <input type="hidden" name="line_id" value={line.id} />
+                    <input type="hidden" name="unit_price" value={(line.unit_price_dirams / 100).toFixed(2)} />
+                    <input name="quantity" type="number" min="1" step="1"
+                           value={line.quantity} on:change={(e) => e.currentTarget.form.requestSubmit()} />
+                  </form>
+                  {#if errors[`line_${line.id}`]}
+                    <small class="field-error">{$t(errors[`line_${line.id}`])}</small>
+                  {/if}
+                </td>
+                <td class="num">
+                  <form method="POST" action="?/update_line" class="inline" use:enhance>
+                    <input type="hidden" name="line_id" value={line.id} />
+                    <input type="hidden" name="quantity" value={line.quantity} />
+                    <input name="unit_price" type="number" step="0.01" min="0"
+                           value={(line.unit_price_dirams / 100).toFixed(2)}
+                           on:change={(e) => e.currentTarget.form.requestSubmit()} />
+                  </form>
+                </td>
+                <td class="num">{formatMoney(lineTotal, lang)}</td>
+                <td>
+                  <form method="POST" action="?/remove_line" class="inline" use:enhance>
+                    <input type="hidden" name="line_id" value={line.id} />
+                    <button type="submit" class="secondary remove" aria-label={$t('common.delete')}>×</button>
+                  </form>
+                </td>
+              </tr>
+            {/each}
+          </tbody>
+          <tfoot>
+            <tr>
+              <td colspan="3" class="num"><strong>{$t('common.total')}</strong></td>
+              <td class="num"><strong>{formatMoney(runningTotalDirams, lang)} {$t('common.currency_short')}</strong></td>
+              <td></td>
+            </tr>
+          </tfoot>
+        </table>
+      {/if}
+    </section>
+
+    {#if errors.save}
+      <div class="error">{$t(errors.save)}</div>
+    {/if}
+
+    <section class="commit">
+      <form method="POST" action="?/save_invoice" class="inline" use:enhance>
+        <button type="submit" class="save">{$t('invoices.save')}</button>
+      </form>
+      <form method="POST" action="?/cancel_invoice" class="inline" on:submit={confirmCancel} use:enhance>
+        <button type="submit" class="danger">{$t('invoices.cancel')}</button>
+      </form>
+    </section>
+  </aside>
+</div>
+
+<style>
+  .title { margin: 0 0 1rem; }
+  .builder {
+    display: grid;
+    grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr);
+    gap: 1.25rem;
+    align-items: start;
+  }
+  .col { display: grid; gap: 1.25rem; }
+  @media (max-width: 900px) {
+    .builder { grid-template-columns: 1fr; }
+  }
+  .running {
+    display: flex;
+    align-items: baseline;
+    justify-content: space-between;
+    gap: 0.75rem;
+    padding: 0.75rem 1.1rem;
+    background: #fff;
+    border: 2px solid #006a4e;
+    border-radius: 8px;
+    box-shadow: 0 1px 2px rgba(0,0,0,0.05);
+  }
+  .total {
+    font-size: 1.35rem;
+    color: #006a4e;
+    font-variant-numeric: tabular-nums;
+  }
+  section.card { padding: 1rem 1.25rem; }
+  section.card h2 { margin-top: 0; }
+  .lines table { margin-top: 0.5rem; }
+  .lines tfoot td { background: #f5f7fb; }
+  .lines input[type=number] {
+    width: 6rem;
+    text-align: right;
+    font-variant-numeric: tabular-nums;
+  }
+  form.inline { display: inline; }
+  .part-search { margin-bottom: 0.35rem; }
+  .field-error { color: #8a1f1b; font-size: 0.8rem; }
+  .actions { display: flex; gap: 0.6rem; }
+  .remove {
+    padding: 0.15rem 0.55rem;
+    font-size: 1.1rem;
+    line-height: 1;
+  }
+  .commit {
+    display: flex;
+    gap: 0.75rem;
+    align-items: center;
+    padding-top: 0.75rem;
+    border-top: 1px solid #e5e8ee;
+  }
+  .commit button.save {
+    padding: 0.75rem 1.5rem;
+    font-size: 1.05rem;
+    font-weight: 600;
+  }
+</style>
diff --git a/static/payment-qr.jpg b/static/payment-qr.jpg
new file mode 100644
index 0000000..20e36ed
Binary files /dev/null and b/static/payment-qr.jpg differ