feat: show liability account credit balances as deposits

apps/api/package.json

@@ -9,7 +9,7 @@
     "db:generate": "prisma generate",
     "db:migrate": "node scripts/database.cjs deploy",
     "db:status": "node scripts/database.cjs status",
-    "test:integration": "tsx --test --test-concurrency=1 test/integration.test.ts test/privacy.test.ts test/icons.test.ts test/transfers.test.ts test/queries.test.ts test/debts.test.ts test/update-integration.test.ts test/record-edit.test.ts test/security-backup.test.ts",
+    "test:integration": "tsx --test --test-concurrency=1 test/integration.test.ts test/privacy.test.ts test/icons.test.ts test/transfers.test.ts test/queries.test.ts test/debts.test.ts test/update-integration.test.ts test/record-edit.test.ts test/security-backup.test.ts test/credit-balance.test.ts",
     "test:performance": "tsx scripts/performance.ts after",
     "icons:seed": "node scripts/seed-icons.cjs"
   },

apps/api/prisma/schema.prisma

@@ -103,6 +103,7 @@ model Revision {
   positionId String @db.Char(36)
   position Position @relation(fields:[positionId],references:[id],onDelete:Cascade)
   /// 变更后的原币绝对余额，不是收支增量，禁止对全部历史求和
+  /// 负债账户正数为欠款，负数为溢缴存款；前端显示符号相反
   amount Decimal @db.Decimal(24,8)
   /// 北京时间业务时间对应的 UTC，精确到分钟
   effectiveDate DateTime @db.DateTime(3)

apps/api/src/backup.ts

@@ -161,11 +161,8 @@ export function validateBackup(raw: unknown) {
     if (!b.currencies.includes(p.currency)) throw new BadRequestException('币种清单不完整');
   }
   for (const p of b.positions)
-    if (
-      (p.kind !== 'account' || p.side !== 'asset') &&
-      p.revisions.some((r) => r.amount.startsWith('-'))
-    )
-      throw new BadRequestException('仅资产账户支持负余额');
+    if (p.kind !== 'account' && p.revisions.some((r) => r.amount.startsWith('-')))
+      throw new BadRequestException('仅账户支持负余额');
   const planIds = new Set<string>();
   for (const plan of b.schedules || []) {
     const source = ids.get(plan.sourceId),

apps/api/src/calculation.ts

@@ -75,6 +75,7 @@ export function totals(positions: Holding[], rates: Rate[], base: string, date:
     const converted = fx ? amount.mul(fx.value) : null;
     if (converted) {
       if (p.side === 'asset') assets = assets.plus(converted);
+      else if (p.kind === 'account' && converted.isNegative()) assets = assets.minus(converted);
       else liabilities = liabilities.plus(converted);
     }
     return {

apps/api/src/openapi.ts

@@ -60,6 +60,12 @@ export function setupOpenApi(app: INestApplication) {
       const operation = entry[method];
       if (!operation) continue;
       operation.summary = `${method.toUpperCase()} ${path}`;
+      if (
+        (path === '/api/positions' && method === 'post') ||
+        (path.startsWith('/api/positions/{id}/revisions') && ['post', 'put'].includes(method))
+      )
+        operation.description =
+          'amount 为数据库原币余额：资产账户正数为存款、负数为透支；负债账户正数为欠款、负数为溢缴存款。网页负债账户输入和显示使用相反符号（负数欠款、正数存款）。独立资产和借入借出债务本金须非负。';
       if (
         method === 'get' &&
         ['/api/history', '/api/positions/{id}/history', '/api/transfers'].includes(path)

apps/api/src/portfolio.ts

@@ -159,8 +159,8 @@ export class PortfolioController {
       });
       if (!p) throw new NotFoundException('项目不存在');
       if (p.archived) throw new ConflictException('请先恢复归档项目');
-      if (v.amount.startsWith('-') && (p.kind !== 'account' || p.side !== 'asset'))
-        throw new BadRequestException('仅资产账户支持负余额');
+      if (v.amount.startsWith('-') && p.kind !== 'account')
+        throw new BadRequestException('仅账户支持负余额');
       const lastTransfer = await tx.revision.findFirst({
         where: { positionId: p.id, reason: { in: pairedReasons } },
         orderBy: [{ effectiveDate: 'desc' }, { sequence: 'desc' }],
@@ -203,8 +203,8 @@ export class PortfolioController {
       });
       if (!p) throw new NotFoundException('项目不存在');
       if (p.archived) throw new ConflictException('请先恢复归档项目');
-      if (v.amount.startsWith('-') && (p.kind !== 'account' || p.side !== 'asset'))
-        throw new BadRequestException('仅资产账户支持负余额');
+      if (v.amount.startsWith('-') && p.kind !== 'account')
+        throw new BadRequestException('仅账户支持负余额');
       const original = await tx.revision.findFirst({ where: { id: revisionId, positionId: p.id } });
       if (!original) throw new NotFoundException('历史记录不存在');
       if (pairedReasons.includes(original.reason))

apps/api/src/replay.ts

@@ -55,7 +55,7 @@ export async function captureReplay(tx: Prisma.TransactionClient, userId: string
       const amount = delta
         ? (balances.get(row.positionId) || new Decimal(0)).plus(delta)
         : new Decimal(row.amount.toString());
-      if (amount.isNegative() && (p.kind !== 'account' || p.side !== 'asset'))
+      if (amount.isNegative() && p.kind !== 'account')
         throw new BadRequestException('修改后债务或资产金额不能为负数');
       if (amount.abs().gte('10000000000000000'))
         throw new BadRequestException('重算后的金额超出支持范围');

apps/api/src/validation.ts

@@ -98,8 +98,8 @@ export const positionInput = positionMeta
   })
   .strict()
   .superRefine((p, c) => {
-    if (p.amount.startsWith('-') && (p.kind !== 'account' || p.side !== 'asset'))
-      c.addIssue({ code: 'custom', message: '仅资产账户支持负余额' });
+    if (p.amount.startsWith('-') && p.kind !== 'account')
+      c.addIssue({ code: 'custom', message: '仅账户支持负余额' });
     if (
       (p.kind === 'asset' && p.side !== 'asset') ||
       (p.kind === 'account' &&

apps/api/test/credit-balance.test.ts

@@ -0,0 +1,193 @@
+import 'dotenv/config';
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { randomUUID, randomBytes, createHash } from 'node:crypto';
+import { PrismaClient } from '@prisma/client';
+import { readBackupZip } from '../src/zip';
+const base = process.env.TEST_API_URL || 'http://127.0.0.1:3100/api';
+test('liability account credit balances survive revisions, replay, calendar, privacy and ZIP restore', async () => {
+  const db = new PrismaClient(),
+    ids: string[] = [];
+  const origin = process.env.WEB_ORIGIN === '*' ? 'http://localhost:5173' : process.env.WEB_ORIGIN!;
+  async function user() {
+    const u = await db.user.create({
+      data: { username: 'wp_credit_' + randomUUID(), passwordHash: 'unused' },
+    });
+    ids.push(u.id);
+    const token = randomBytes(32).toString('hex');
+    await db.session.create({
+      data: {
+        id: createHash('sha256').update(token).digest('hex'),
+        userId: u.id,
+        expiresAt: new Date(Date.now() + 3600000),
+      },
+    });
+    return { id: u.id, cookie: 'wp_session=' + token };
+  }
+  async function call(path: string, cookie: string, method = 'GET', body?: unknown) {
+    const res = await fetch(base + path, {
+      method,
+      headers: {
+        Cookie: cookie,
+        Origin: origin,
+        ...(body ? { 'Content-Type': 'application/json' } : {}),
+      },
+      body: body ? JSON.stringify(body) : undefined,
+    });
+    return { status: res.status, data: await res.json() };
+  }
+  try {
+    const a = await user(),
+      b = await user();
+    const initial = {
+      name: 'Card',
+      kind: 'account',
+      side: 'liability',
+      category: 'credit_card',
+      currency: 'CNY',
+      amount: '100',
+      date: '2026-09-01T10:00',
+    };
+    const create = await call('/positions', a.cookie, 'POST', initial);
+    assert.equal(create.status, 201);
+    const id = create.data.id;
+    const balance = async (amount: string, date = '2026-09-02T10:00') =>
+      call('/positions/' + id + '/revisions', a.cookie, 'POST', {
+        amount,
+        date,
+        reason: 'balance',
+      });
+    const credit = await balance('-25');
+    assert.equal(credit.status, 201);
+    assert.equal((await call('/positions/' + id, a.cookie)).data.amount, '-25');
+    let totals = (await call('/overview', a.cookie)).data;
+    assert.equal(totals.assets, '25.00');
+    assert.equal(totals.liabilities, '0.00');
+    assert.equal(totals.net, '25.00');
+    let day = (await call('/calendar/day?date=2026-09-02', a.cookie)).data;
+    assert.equal(day.items[0].amount, '125');
+    assert.equal(day.items[0].direction, 'income');
+    assert.equal(
+      (
+        await call('/positions/' + id + '/revisions/' + credit.data.id, b.cookie, 'PUT', {
+          amount: '-30',
+          date: '2026-09-02T10:00',
+        })
+      ).status,
+      404,
+    );
+    assert.equal(
+      (
+        await call('/positions/' + id + '/revisions/' + credit.data.id, a.cookie, 'PUT', {
+          amount: '-30',
+          date: '2026-09-02T10:00',
+        })
+      ).status,
+      200,
+    );
+    assert.equal((await call('/overview', a.cookie)).data.assets, '30.00');
+    assert.equal(
+      (await call('/calendar/day?date=2026-09-02', a.cookie)).data.items[0].amount,
+      '130',
+    );
+    assert.equal(
+      (await call('/positions/' + id + '/revisions/' + credit.data.id, a.cookie, 'DELETE')).status,
+      200,
+    );
+    assert.equal((await call('/overview', a.cookie)).data.liabilities, '100.00');
+    await balance('-20');
+    await balance('10', '2026-09-03T10:00');
+    day = (await call('/calendar/day?date=2026-09-03', a.cookie)).data;
+    assert.equal(day.items[0].direction, 'expense');
+    assert.equal(day.items[0].amount, '30');
+    const history = (await call('/positions/' + id + '/history', a.cookie)).data.items;
+    await call('/positions/' + id + '/revisions/' + history[0].id, a.cookie, 'DELETE');
+    assert.equal((await call('/positions/' + id, a.cookie)).data.amount, '-20');
+    assert.equal(
+      (
+        await call('/positions', a.cookie, 'POST', {
+          ...initial,
+          name: 'Initial credit',
+          amount: '-5.01',
+        })
+      ).status,
+      201,
+    );
+    assert.equal(
+      (
+        await call('/positions', a.cookie, 'POST', {
+          ...initial,
+          name: 'Debt',
+          kind: 'debt',
+          category: 'personal',
+          amount: '10',
+        })
+      ).status,
+      201,
+    );
+    assert.equal(
+      (
+        await call('/positions', a.cookie, 'POST', {
+          ...initial,
+          name: 'Invalid debt',
+          kind: 'debt',
+          category: 'personal',
+          amount: '-1',
+        })
+      ).status,
+      400,
+    );
+    assert.equal(
+      (
+        await call('/positions', a.cookie, 'POST', {
+          ...initial,
+          name: 'Invalid asset',
+          kind: 'asset',
+          side: 'asset',
+          category: 'other',
+          amount: '-1',
+        })
+      ).status,
+      400,
+    );
+    totals = (await call('/overview', a.cookie)).data;
+    assert.equal(totals.assets, '25.01');
+    assert.equal(totals.liabilities, '10.00');
+    assert.equal(totals.net, '15.01');
+    const trend = (await call('/trend?from=2026-09-01&to=2026-09-03', a.cookie)).data.items;
+    assert.equal(trend[0].assets, '5.01');
+    assert.equal(trend[0].liabilities, '110.00');
+    assert.equal(trend[1].assets, '25.01');
+    assert.equal(trend[1].liabilities, '10.00');
+    const zip = await fetch(base + '/backup', { headers: { Cookie: a.cookie } });
+    assert.equal(zip.status, 200);
+    const backup: any = await readBackupZip(Buffer.from(await zip.arrayBuffer()));
+    assert.equal(
+      (await call('/backup/import', b.cookie, 'POST', { confirmed: true, backup })).status,
+      201,
+    );
+    const restored = (await call('/overview', b.cookie)).data;
+    assert.equal(restored.assets, '25.01');
+    assert.equal(restored.liabilities, '10.00');
+    assert.equal(restored.net, '15.01');
+    assert.equal(
+      (await call('/calendar/day?date=2026-09-02', b.cookie)).data.items[0].amount,
+      '120',
+    );
+    assert.equal(
+      (
+        await call('/positions/' + id, a.cookie, 'PATCH', {
+          name: 'Card',
+          category: 'credit_card',
+          hidden: true,
+        })
+      ).status,
+      200,
+    );
+    assert.equal((await call('/positions/' + id, a.cookie)).status, 404);
+    assert.equal((await call('/overview', a.cookie)).data.assets, '5.01');
+  } finally {
+    await db.user.deleteMany({ where: { id: { in: ids } } });
+    await db.$disconnect();
+  }
+});

apps/api/test/update.test.ts

@@ -7,7 +7,7 @@ import { executeMovement } from '../src/transfers';
 import { transferInput, positionInput, revisionInput } from '../src/validation';
 import { scheduleInput, occurrenceId, nextOccurrence, SchedulesController } from '../src/schedules';
 import { trend, totals, type Holding } from '../src/calculation';
-import { positionAmount, money, type Position } from '../../web/src/api';
+import { positionAmount, accountInputAmount, money, type Position } from '../../web/src/api';
 const now = new Date(Date.now() - 60000);
 const date = new Date(+now + 8 * 3600000).toISOString().slice(0, 16);
 function fixture(
@@ -114,7 +114,7 @@ test('transfer into an overdrawn account is allowed; debt overpayment still fail
   assert.equal(debt.balances.get(debt.sourceId), '-11');
   assert.equal(debt.balances.get(debt.targetId), '0');
 });
-test('negative balances are confined to asset accounts; group names and principal remain validated', () => {
+test('negative balances are confined to accounts; group names and debt principal remain validated', () => {
   const data = {
     name: 'test',
     category: 'bank',
@@ -127,7 +127,7 @@ test('negative balances are confined to asset accounts; group names and principa
   };
   assert.equal(positionInput.parse(data).groupName, '日常');
   assert.equal(positionInput.safeParse({ ...data, kind: 'debt' }).success, false);
-  assert.equal(positionInput.safeParse({ ...data, side: 'liability' }).success, false);
+  assert.equal(positionInput.safeParse({ ...data, side: 'liability' }).success, true);
   assert.equal(positionInput.safeParse({ ...data, groupName: 'a'.repeat(61) }).success, false);
   assert.equal(revisionInput.parse({ amount: '-0.00000001', date }).amount, '-0.00000001');
   assert.equal(transferInput.safeParse({ ...fixture().request, amount: '-1' }).success, false);
@@ -343,3 +343,82 @@ test('calendar replays only the range, preserves fractional totals, and hides in
   assert.equal(month.items[2].complete, false);
   assert.equal(month.items.length, 30);
 });
+
+test('liability account credit balances invert display and input without losing decimal precision', () => {
+  const card = {
+    kind: 'account',
+    side: 'liability',
+    amount: '-9999999999999999.12345678',
+  } as Position;
+  assert.equal(positionAmount(card), '9999999999999999.12345678');
+  assert.equal(positionAmount(card, '12.12345678'), '-12.12345678');
+  assert.equal(positionAmount(card, '-0.00000000'), '0.00000000');
+  assert.equal(accountInputAmount(card, '12.12345678'), '-12.12345678');
+  assert.equal(accountInputAmount(card, '-12.12345678'), '12.12345678');
+  assert.equal(accountInputAmount({ ...card, kind: 'debt' }, '12.12345678'), '12.12345678');
+});
+test('credit balances count as assets across zero, retain FX attribution and do not offset other liabilities', () => {
+  const card: Holding = {
+    id: randomUUID(),
+    name: 'Card',
+    kind: 'account',
+    side: 'liability',
+    currency: 'USD',
+    revisions: [
+      {
+        id: 'a',
+        amount: '100',
+        effectiveDate: new Date('2026-09-01'),
+        reason: 'initial',
+        notes: '',
+      },
+      {
+        id: 'b',
+        amount: '-25',
+        effectiveDate: new Date('2026-09-02'),
+        reason: 'balance',
+        notes: '',
+      },
+    ],
+  };
+  const rates = [
+    {
+      currency: 'USD',
+      baseCurrency: 'CNY',
+      date: new Date('2026-09-01'),
+      rate: '7',
+      source: 'manual',
+    },
+    {
+      currency: 'USD',
+      baseCurrency: 'CNY',
+      date: new Date('2026-09-02'),
+      rate: '8',
+      source: 'manual',
+    },
+  ];
+  const owing = totals([card], rates, 'CNY', '2026-09-01');
+  assert.equal(owing.assets, '0.00');
+  assert.equal(owing.liabilities, '700.00');
+  assert.equal(owing.net, '-700.00');
+  const credit = totals([card], rates, 'CNY', '2026-09-02');
+  assert.equal(credit.assets, '200.00');
+  assert.equal(credit.liabilities, '0.00');
+  assert.equal(credit.net, '200.00');
+  const rows = trend([card], rates, 'CNY', '2026-09-01', '2026-09-02');
+  assert.equal(rows[1].fxChange, '-100.00');
+  assert.equal(rows[1].balanceChange, '1000.00');
+  const debt = {
+    ...card,
+    id: randomUUID(),
+    kind: 'debt',
+    currency: 'CNY',
+    revisions: [{ ...card.revisions[0], amount: '20' }],
+  };
+  const mixed = totals([card, debt], rates, 'CNY', '2026-09-02');
+  assert.equal(mixed.assets, '200.00');
+  assert.equal(mixed.liabilities, '20.00');
+  assert.equal(mixed.net, '180.00');
+  assert.equal(cashflowDelta('liability', 'balance', '100', '-25').toFixed(), '125');
+  assert.equal(cashflowDelta('liability', 'balance', '-25', '10').toFixed(), '-35');
+});

apps/web/src/App.tsx

@@ -25,6 +25,7 @@ import {
   currencies,
   money,
   positionAmount,
+  accountInputAmount,
   today,
   nowMinute,
   displayTime,
@@ -1157,16 +1158,14 @@ export default function App() {
                         ? tr(p.side === 'asset' ? '借款（待收）' : '欠款（待还）')
                         : p.side === 'asset'
                           ? tr('资产')
-                          : tr('负债')}
+                          : tr(
+                              p.kind === 'account' && p.amount.startsWith('-')
+                                ? '溢缴存款'
+                                : '负债',
+                            )}
                       {p.archived ? tr(' · 已归档') : ''}
                     </span>
-                    <h2
-                      className={
-                        p.side === 'liability' || p.amount.startsWith('-')
-                          ? 'danger-text'
-                          : undefined
-                      }
-                    >
+                    <h2 className={positionAmount(p).startsWith('-') ? 'danger-text' : undefined}>
                       {money(positionAmount(p), p.currency)}
                     </h2>
                     {p.hidden && <span className="badge">{tr('隐藏项目')}</span>}
@@ -1368,14 +1367,16 @@ export default function App() {
                               ? tr(p.side === 'asset' ? '借款（待收）' : '欠款（待还）')
                               : p.side === 'asset'
                                 ? tr('资产')
-                                : tr('负债')}
+                                : tr(
+                                    p.kind === 'account' && p.amount.startsWith('-')
+                                      ? '溢缴存款'
+                                      : '负债',
+                                  )}
                             {p.archived ? tr(' · 已归档') : ''}
                           </p>
                           <strong
                             className={
-                              p.side === 'liability' || p.amount.startsWith('-')
-                                ? 'danger-text'
-                                : undefined
+                              positionAmount(p).startsWith('-') ? 'danger-text' : undefined
                             }
                           >
                             {money(positionAmount(p), p.currency)}
@@ -2262,7 +2263,7 @@ export default function App() {
                       api(
                         '/positions/' + mp!.id + '/revisions' + (modal.h ? '/' + modal.h.id : ''),
                         modal.h ? 'PUT' : 'POST',
-                        v,
+                        { ...v, amount: accountInputAmount(mp!, String(v.amount)) },
                       ),
                     tr('金额历史已保存，总览已重新计算'),
                   );
@@ -2292,6 +2293,7 @@ export default function App() {
                         ...(f.has('iconId') ? { iconId: f.get('iconId') || null } : {}),
                         kind,
                         side,
+                        amount: accountInputAmount({ kind, side }, String(v.amount)),
                         hidden: f.get('hidden') === 'on',
                       }),
                     tr('项目已添加'),
@@ -2360,7 +2362,7 @@ export default function App() {
                   </Field>
                   {modal.kind === 'account' && (
                     <p className="muted">
-                      {tr('信用卡、贷款账户自动计入负债，其余账户计入资产。')}
+                      {tr('信用卡、贷款账户：负数为欠款，正数为溢缴存款；其余账户按实际余额填写。')}
                     </p>
                   )}
                 </>
@@ -2406,13 +2408,16 @@ export default function App() {
                     inputMode="decimal"
                     required
                     pattern={
-                      (modal.p?.side === 'asset' && modal.p?.kind === 'account') ||
-                      modal.kind === 'account'
+                      modal.p?.kind === 'account' || modal.kind === 'account'
                         ? '-?(0|[1-9][0-9]{0,15})(\\.[0-9]{1,8})?'
                         : '(0|[1-9][0-9]{0,15})(\\.[0-9]{1,8})?'
                     }
                     defaultValue={
-                      modal.h?.after || modal.p?.amount || (modal.kind === 'debt' ? '0' : '')
+                      modal.p
+                        ? accountInputAmount(modal.p, modal.h?.after || modal.p.amount)
+                        : modal.kind === 'debt'
+                          ? '0'
+                          : ''
                     }
                     placeholder="0.00"
                   />
@@ -2430,6 +2435,13 @@ export default function App() {
                   />
                 </Field>
               )}
+              {['revision', 'correction'].includes(modal.kind) &&
+                modal.p?.kind === 'account' &&
+                modal.p.side === 'liability' && (
+                  <p className="muted">
+                    {tr('负数表示欠款，正数表示溢缴存款；溢缴部分计入总资产。')}
+                  </p>
+                )}
               {modal.kind === 'revision' && (
                 <>
                   <Field label={tr('变更原因')}>
@@ -2575,42 +2587,19 @@ function HistoryTable({
                 </small>
               </td>
               <td
-                className={h.kind === 'debt' && h.side === 'liability' ? 'danger-text' : undefined}
+                className={positionAmount(h, h.before).startsWith('-') ? 'danger-text' : undefined}
               >
-                {money(
-                  h.kind === 'debt' && h.side === 'liability' && Number(h.before) !== 0
-                    ? '-' + h.before
-                    : h.before,
-                  h.currency,
-                )}
+                {money(positionAmount(h, h.before), h.currency)}
               </td>
               <td
-                className={h.kind === 'debt' && h.side === 'liability' ? 'danger-text' : undefined}
+                className={positionAmount(h, h.after).startsWith('-') ? 'danger-text' : undefined}
               >
-                {money(
-                  h.kind === 'debt' && h.side === 'liability' && Number(h.after) !== 0
-                    ? '-' + h.after
-                    : h.after,
-                  h.currency,
-                )}
+                {money(positionAmount(h, h.after), h.currency)}
               </td>
               <td
-                className={
-                  (h.kind === 'debt' && h.side === 'liability') || h.delta.startsWith('-')
-                    ? 'danger-text'
-                    : undefined
-                }
+                className={positionAmount(h, h.delta).startsWith('-') ? 'danger-text' : undefined}
               >
-                {money(
-                  h.kind === 'debt' && h.side === 'liability'
-                    ? h.delta.startsWith('-')
-                      ? h.delta.slice(1)
-                      : Number(h.delta) !== 0
-                        ? '-' + h.delta
-                        : h.delta
-                    : h.delta,
-                  h.currency,
-                )}
+                {money(positionAmount(h, h.delta), h.currency)}
               </td>
               <td className="notes-cell">{h.notes || '—'}</td>
               {correct && (

apps/web/src/api.ts

@@ -140,8 +140,15 @@ export function requestUuid() {
 
 export type PageResult<T> = { items: T[]; nextCursor: string | null; revealed: boolean };
 
-export function positionAmount(p: Position, value = p.amount) {
-  return p.kind === 'debt' && p.side === 'liability' && !/^[-]?0(?:\.0+)?$/.test(value)
-    ? '-' + value.replace(/^-/, '')
-    : value;
+// Stored liability balances are amounts owed; negative account balances are credit.
+export function positionAmount(
+  p: Pick<Position, 'side'> & { amount?: string },
+  value = p.amount || '0',
+) {
+  if (p.side !== 'liability' || /^-?0(?:\.0+)?$/.test(value))
+    return value.replace(/^-0(?=\.0+$|$)/, '0');
+  return value.startsWith('-') ? value.slice(1) : '-' + value;
+}
+export function accountInputAmount(p: Pick<Position, 'kind' | 'side'>, value: string) {
+  return p.kind === 'account' ? positionAmount(p, value) : value;
 }

apps/web/src/locales/en.json

@@ -463,5 +463,9 @@
   "备份下载失败": "Backup download failed.",
   "备份文件格式错误": "Invalid backup file format.",
   "备份文件为空": "The backup file is empty.",
-  "备份已生成，请确认文件已保存": "Backup generated. Please confirm the file has been saved."
+  "备份已生成，请确认文件已保存": "Backup generated. Please confirm the file has been saved.",
+  "溢缴存款": "Credit balance",
+  "信用卡、贷款账户：负数为欠款，正数为溢缴存款；其余账户按实际余额填写。": "Credit cards and loan accounts: negative means debt, positive means credit. Enter the actual balance for other accounts.",
+  "负数表示欠款，正数表示溢缴存款；溢缴部分计入总资产。": "Negative means debt, positive means credit. Credit balances count towards total assets.",
+  "仅账户支持负余额": "Only accounts support negative balances."
 }

apps/web/src/locales/zh-Hant.json

@@ -463,5 +463,9 @@
   "备份下载失败": "備份下載失敗",
   "备份文件格式错误": "備份檔案格式錯誤",
   "备份文件为空": "備份檔案為空",
-  "备份已生成，请确认文件已保存": "備份已產生，請確認檔案已保存"
+  "备份已生成，请确认文件已保存": "備份已產生，請確認檔案已保存",
+  "溢缴存款": "溢繳存款",
+  "信用卡、贷款账户：负数为欠款，正数为溢缴存款；其余账户按实际余额填写。": "信用卡、貸款賬戶：負數為欠款，正數為溢繳存款；其餘賬戶按實際餘額填寫。",
+  "负数表示欠款，正数表示溢缴存款；溢缴部分计入总资产。": "負數表示欠款，正數表示溢繳存款；溢繳部分計入總資產。",
+  "仅账户支持负余额": "僅賬戶支援負餘額"
 }

docs/acceptance.md

@@ -66,3 +66,7 @@
 ## 2026-10-03 账号、删除与备份修复
 
 28 项单元测试、11 项真实 MySQL 集成检查、前后端类型检查和生产构建通过。新增账号凭据变更与会话撤销、配对历史直接删除、零历史项目及 ZIP 上传恢复验证；浏览器确认删除弹窗和修改后的自动刷新。详情与验证边界见 [更新说明](update-2026-10-03.md)。无数据库结构变更。
+
+## 2026-10-03 负债账户溢缴存款
+
+30 项单元测试、12 项真实 MySQL 集成检查、类型检查及构建通过。浏览器验证信用卡从欠款转为正数溢缴存款并计入总资产，余额历史与总览自动刷新；补充金额精度、趋势、日历、权限和备份恢复断言。无数据库结构变更。详见 [更新说明](update-credit-balance-2026-10-03.md)。

docs/architecture.md

@@ -45,3 +45,5 @@ User.hiddenMenus 保存受枚举校验的菜单键，settings 不可隐藏；Use
 2026-10-02 记录编辑更新：允许更正转账之前的独立余额历史。`replay.ts` 重放涉及项目的历史，绝对余额保留为锚点，配对资金往来与定时支出按增量更新；整笔修改/删除与两侧余额在同一事务提交。单侧配对历史禁止独立更正；2026-10-03 更新后，从任一侧删除会原子删除完整配对记录。日历读取保存后的账户历史重算。完整边界见 [更新说明](update-2026-10-02.md)。
 
 2026-10-03 修复：历史重放允许没有绝对余额锚点时从零计算增量，空历史项目金额为零；备份校验、转账和计划支出使用相同规则。账号凭据变更锁定用户行、验证当前密码、更新凭据并在同一事务撤销旧会话和创建新会话；无需新增字段。/auth/me 返回完整隐藏授权状态和会话时间。前端 mutation 更新数据版本，以当前页面重新读取数据，旧视图请求通过 generation 检查丢弃。见 [更新说明](update-2026-10-03.md)。
+
+2026-10-03 负债账户溢缴更新：负债账户存储正数欠款、负数溢缴；前端显示和输入取相反符号。统计将负债账户的负余额按汇率转换为正资产，正欠款计入负债，两类分别汇总。独立资产和借入借出债务仍要求非负本金，旧数据和 API 金额含义保留。详见 [溢缴更新说明](update-credit-balance-2026-10-03.md)。

docs/update-credit-balance-2026-10-03.md

@@ -0,0 +1,26 @@
+# 2026-10-03 负债账户溢缴存款
+
+## 使用方式
+
+信用卡和贷款等负债账户的余额输入、列表、详情及历史统一使用有符号余额：负数表示欠款，正数表示溢缴存款。例如欠款 100 填写 -100，溢缴存款 100 填写 100。零表示无欠款或存款。快速记账、余额更新、历史更正和新建账户使用相同规则，表单说明已同步更新。
+
+溢缴账户标记为“溢缴存款”，正数不显示为负债红色；欠款和负向变化显示红色。溢缴款按原币和可用历史汇率计入总资产，欠款计入总负债，不用溢缴款抵消其他账户的负债。净资产始终按总资产减总负债计算，趋势和汇率归因也按同一逻辑重放。
+
+收支日历沿用负债方向计算。例如从欠款 100 到溢缴存款 25，余额净增加 125；从溢缴存款 25 到欠款 10，余额净减少 35。初始余额、估值和配对资金操作仍按原规则排除。
+
+## 数据与兼容性
+
+数据库和现有 API 保留原来的负债本金符号：正数为欠款，负数为溢缴存款；网页输入和显示进行无损字符串符号转换。已有正数欠款数据仍表示同一欠款，原币金额没有批量改写。资产账户仍按原币余额存储和显示；独立资产及借入借出债务仍要求非负本金。
+
+创建、更新、更正、删除后的历史重放和备份校验均允许负债账户的负余额。ZIP 恢复保存负债账户类型、原币和历史，不把项目永久改为资产类型；同一账户可以再次从溢缴转为欠款。此次未扩大账户转账或计划支持的账户范围。
+
+复用现有字段，无数据库结构变更和新迁移。数据库已有表、字段注释保留；Prisma 的余额字段注释补充了负债符号含义，OpenAPI 补充了网页与 API 的符号约定。
+
+## 验证
+
+- 30 项单元测试、12 项真实 MySQL 集成检查通过；前后端类型检查和生产构建通过。
+- 新增断言覆盖八位小数和大金额字符串无损转换、跨越零余额、溢缴款与其他债务分别汇总、历史趋势及 FX 归因、日历方向、更正和删除重算、跨用户和隐藏权限、ZIP 导出与恢复。
+- 浏览器使用临时模拟账号，将欠款 -100 更新为溢缴存款 120.12345678，详情、历史和总览自动刷新；总资产 120.12、总负债 0.00、净资产 120.12。未操作实际用户账户或进行真实资金转移。
+- 临时账号、模拟数据和预览配置在验收后清理。保留用户原有 Vite 配置修改，仅本地提交，不 push。
+
+![溢缴存款显示](credit-balance-preview.png)

update.md

@@ -32,6 +32,8 @@
 - ~~删除记录有问题，有时候无法删除，UI也不对~~ — 已完成并验证：2026-10-03 11:22
 - ~~删除记录后部分UI需要手动刷新~~ — 已完成并验证：2026-10-03 11:22
 - ~~备份功能出现问题~~ — 已完成并验证：2026-10-03 11:22
+- ~~负债（如信用卡）也可以显示为正数变成存款~~ — 已完成并验证：2026-10-03 12:05
+- 分组可以排序
 
 验证与部署边界见 [更新说明](docs/update-2026-10-02.md)。
 
@@ -40,3 +42,5 @@
 本轮补充验收完成：2026-10-02 18:44。13 个迁移状态最新，34 个内置图标已初始化；28 项单元测试、10 项真实数据库集成检查通过，9 张表与 88 个字段注释已核验。重新检查文档，无新增未完成要求。
 
 本轮验收完成：2026-10-03 11:22。28 项单元测试、11 项真实 MySQL 集成检查、前后端类型检查与生产构建通过；未新增数据库表或字段。账号、删除与备份更新详情见 [更新说明](docs/update-2026-10-03.md)。重新检查文档，无新增未完成要求。
+
+负债账户溢缴验收完成：2026-10-03 12:05。30 项单元测试、12 项真实 MySQL 集成检查、类型检查和构建通过；支持信用卡等负债账户正数存款显示及总资产分类，已有数据符号保留。详见 [更新说明](docs/update-credit-balance-2026-10-03.md)。复查发现新增“分组可以排序”，继续处理。