diff --git a/deploy/.env.staging.identity.example b/deploy/.env.staging.identity.example
index be70e398..037b55c6 100644
--- a/deploy/.env.staging.identity.example
+++ b/deploy/.env.staging.identity.example
@@ -17,6 +17,10 @@ ADMIN_DATABASE_URL=postgresql://admin_runtime:<percent-encoded-admin-runtime-pas
 BETTER_AUTH_USER_SECRET=<independent-openssl-rand-base64-32-output>
 RESEND_API_KEY=<staging-only-resend-api-key>
 RESEND_FROM_EMAIL=Jyotisha Staging <login@staging.jyotisha.chat>
+# Optional test-only OTP channel: when set to a 6-digit code, no real email is
+# delivered; the login page shows the fixed code so testers can register/login
+# without a mailbox. Never set in production. Omit (or empty) to disable.
+#IDENTITY_TEST_OTP=123456
 ADMIN_EMAILS=<comma-separated-staging-admin-emails>
 EPAY_CONFIG_ENCRYPTION_KEY=<independent-openssl-rand-base64-32-output>
 MODEL_PROVIDER_CONFIG_ENCRYPTION_KEY=<independent-openssl-rand-base64-32-output>
diff --git a/frontend/src/app/globals.css b/frontend/src/app/globals.css
index 7c099f36..9d4335c3 100644
--- a/frontend/src/app/globals.css
+++ b/frontend/src/app/globals.css
@@ -819,6 +819,8 @@ input:not([class^="ant-"]):not([class*=" ant-"]):not(.ant-picker input):disabled
 .auth-brand { align-items: center; gap: 10px; font-size: 17px; display: none; margin-bottom: var(--space-10); }
 .auth-panel h1 { font-size: var(--type-display-md); }
 .page-intro { line-height: 1.6; margin: var(--space-3) 0 var(--space-8); color: var(--color-ink-secondary); font-size: var(--type-body-md); }
+.auth-test-channel { margin: 0 0 var(--space-6); padding: 10px 12px; border: 1px dashed color-mix(in srgb, var(--color-action) 40%, var(--color-border)); border-radius: var(--radius-md); background: var(--color-action-soft); color: var(--color-ink-secondary); line-height: 1.5; font-size: var(--type-caption); }
+.auth-test-channel strong { color: var(--color-action); font-family: var(--font-mono); font-size: 15px; font-variant-numeric: tabular-nums; letter-spacing: .12em; }
 .stack-form { display: grid; gap: var(--space-3); }
 .stack-form label { font-size: 13px; }
 .stack-form .button-primary { margin-top: var(--space-2); }
@@ -1763,14 +1765,15 @@ input:not([class^="ant-"]):not([class*=" ant-"]):not(.ant-picker input):disabled
   gap: 14px;
   margin: 8px 0 16px;
   padding: 18px;
-  border: 1px solid var(--border);
-  border-radius: 16px;
-  background: color-mix(in srgb, var(--card) 92%, transparent);
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-xl);
+  background: linear-gradient(180deg, var(--color-canvas-muted) 0%, var(--color-canvas) 100%);
+  box-shadow: var(--shadow-soft);
 }
 .rectification-candidates-heading { display: grid; gap: 5px; }
-.rectification-candidates-heading strong { font-size: 16px; }
+.rectification-candidates-heading strong { font-size: var(--type-title-sm); font-family: var(--font-display); font-weight: 600; letter-spacing: -.2px; }
 .rectification-candidates-heading span,
-.rectification-candidate-support { color: var(--muted-foreground); font-size: 12px; line-height: 1.5; }
+.rectification-candidate-support { color: var(--color-ink-secondary); font-size: var(--type-caption); line-height: 1.5; }
 .rectification-candidate-list {
   display: grid;
   width: 100%;
@@ -1784,33 +1787,38 @@ input:not([class^="ant-"]):not([class*=" ant-"]):not(.ant-picker input):disabled
   min-width: 0;
   min-height: 132px;
   padding: 14px;
-  border: 1px solid var(--border);
-  border-radius: 12px;
-  color: var(--foreground);
-  background: var(--card);
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-lg);
+  color: var(--color-ink);
+  background: var(--color-canvas);
   font: inherit;
   text-align: left;
   cursor: pointer;
+  transition: border-color 120ms ease-out, background-color 120ms ease-out, transform 120ms ease-out, box-shadow 120ms ease-out;
 }
-.rectification-candidate:hover:not(:disabled) { border-color: color-mix(in srgb, var(--primary) 45%, var(--border)); }
-.rectification-candidate:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; }
+.rectification-candidate:hover:not(:disabled) {
+  border-color: color-mix(in srgb, var(--color-action) 45%, var(--color-border));
+  transform: translateY(-1px);
+  box-shadow: var(--shadow-soft);
+}
+.rectification-candidate:focus-visible { outline: 2px solid var(--color-focus); outline-offset: 2px; }
 .rectification-candidate:disabled { cursor: default; opacity: 1; }
 .rectification-candidate.is-selected {
-  border-color: color-mix(in srgb, var(--primary) 55%, var(--border));
-  background: color-mix(in srgb, var(--primary) 7%, var(--card));
+  border-color: color-mix(in srgb, var(--color-action) 55%, var(--color-border));
+  background: color-mix(in srgb, var(--color-action-soft) 60%, var(--color-canvas));
 }
 .rectification-candidate-time { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
-.rectification-candidate-time strong { font-size: 22px; font-variant-numeric: tabular-nums; }
+.rectification-candidate-time strong { font-size: var(--type-title-md); font-family: var(--font-display); font-weight: 600; font-variant-numeric: tabular-nums; letter-spacing: -.2px; }
 .rectification-candidate-badge {
   padding: 2px 7px;
   border-radius: 999px;
-  color: var(--primary) !important;
-  background: color-mix(in srgb, var(--primary) 10%, transparent);
+  color: var(--color-action) !important;
+  background: color-mix(in srgb, var(--color-action) 10%, transparent);
   font-size: 11px !important;
   font-weight: 650;
 }
-.rectification-candidate-action { align-self: end; color: var(--primary); font-size: 13px; font-weight: 650; }
-.rectification-saved { margin: 8px 0 16px; color: var(--foreground); font-size: 14px; }
+.rectification-candidate-action { align-self: end; color: var(--color-action); font-size: 13px; font-weight: 650; }
+.rectification-saved { margin: 8px 0 16px; color: var(--color-ink); font-size: var(--type-body-sm); }
 @media (max-width: 640px) {
   .rectification-candidates { padding: 14px; }
   .rectification-candidate-list {
diff --git a/frontend/src/app/login/page.tsx b/frontend/src/app/login/page.tsx
index 0570f487..649818a4 100644
--- a/frontend/src/app/login/page.tsx
+++ b/frontend/src/app/login/page.tsx
@@ -19,6 +19,7 @@ export default async function LoginPage() {
       provider={config.provider}
       passwordEnabled={config.provider === "self-hosted"}
       successPath={successPath}
+      testOtp={config.provider === "self-hosted" ? config.testOtp : null}
     />
   );
 }
diff --git a/frontend/src/components/email-otp-login.tsx b/frontend/src/components/email-otp-login.tsx
index 66ccc900..d6c15c41 100644
--- a/frontend/src/components/email-otp-login.tsx
+++ b/frontend/src/components/email-otp-login.tsx
@@ -39,11 +39,13 @@ export function EmailOtpLogin({
   passwordEnabled = false,
   passwordOnly = false,
   successPath = "/",
+  testOtp = null,
 }: {
   provider: AuthProvider;
   passwordEnabled?: boolean;
   passwordOnly?: boolean;
   successPath?: "/" | "/admin";
+  testOtp?: string | null;
 }) {
   const [mode, setMode] = useState<AuthMode>(passwordOnly ? "password" : "otp");
   const [step, setStep] = useState<AuthStep>("email");
@@ -57,6 +59,7 @@ export function EmailOtpLogin({
   const [notice, setNotice] = useState("");
 
   const canUsePassword = provider === "self-hosted" && passwordEnabled;
+  const testMode = testOtp !== null && testOtp !== undefined && testOtp !== "";
   const showLoginNavigation =
     step === "email"
     && canUsePassword
@@ -307,6 +310,12 @@ export function EmailOtpLogin({
           <h1 id="login-title">{title}</h1>
           <p className="page-intro">{intro}</p>
 
+          {testMode && (
+            <p className="auth-test-channel" role="status">
+              测试环境：验证码固定为 <strong>{testOtp}</strong>，不会发送真实邮件。
+            </p>
+          )}
+
           {showLoginNavigation && (
             <nav className="auth-mode-nav" aria-label="登录方式">
               <div className="auth-mode-tabs">
diff --git a/frontend/src/modules/identity/auth-factory.ts b/frontend/src/modules/identity/auth-factory.ts
index 9c1ccc96..9814102f 100644
--- a/frontend/src/modules/identity/auth-factory.ts
+++ b/frontend/src/modules/identity/auth-factory.ts
@@ -35,6 +35,7 @@ export function createEmailOtpOptions(
   sender: EmailOtpSender,
   secret: string,
   disableSignUp: boolean,
+  testOtp: string | null = null,
 ): EmailOTPOptions {
   return {
     otpLength: 6,
@@ -44,14 +45,30 @@ export function createEmailOtpOptions(
     storeOTP: "hashed",
     disableSignUp,
     rateLimit: { window: 60, max: 3 },
-    async sendVerificationOTP({ email, otp, type }) {
-      await sender.send({
-        email,
-        otp,
-        type,
-        idempotencyKey: otpIdempotencyKey(secret, email, otp, type),
-      });
-    },
+    ...(testOtp
+      ? {
+          generateOTP: () => testOtp,
+          async sendVerificationOTP({ email, otp, type }) {
+            // Test channel: no real email is delivered; the fixed code is
+            // surfaced by the login UI when IDENTITY_TEST_OTP is configured.
+            await sender.send({
+              email,
+              otp,
+              type,
+              idempotencyKey: otpIdempotencyKey(secret, email, otp, type),
+            });
+          },
+        }
+      : {
+          async sendVerificationOTP({ email, otp, type }) {
+            await sender.send({
+              email,
+              otp,
+              type,
+              idempotencyKey: otpIdempotencyKey(secret, email, otp, type),
+            });
+          },
+        }),
   };
 }
 
@@ -96,7 +113,7 @@ export function buildAuthOptions({
       revokeSessionsOnPasswordReset: true,
     },
     plugins: [
-      emailOTP(createEmailOtpOptions(emailSender, config.userSecret, false)),
+      emailOTP(createEmailOtpOptions(emailSender, config.userSecret, false, config.testOtp)),
       twoFactor({
         issuer: "Jyotisha Admin",
         twoFactorTable: "two_factors",
diff --git a/frontend/src/modules/identity/auth.ts b/frontend/src/modules/identity/auth.ts
index 584f2544..85e7e958 100644
--- a/frontend/src/modules/identity/auth.ts
+++ b/frontend/src/modules/identity/auth.ts
@@ -8,6 +8,7 @@ import {
   type SelfHostedIdentityConfig,
 } from "./config.ts";
 import type { EmailOtpSender } from "./contracts.ts";
+import { FakeEmailOtpSender } from "./email/fake-email-otp-sender.ts";
 import { ResendEmailOtpSender } from "./email/resend-email-otp-sender.ts";
 
 interface AdminRoleRow {
@@ -88,10 +89,12 @@ export function createIdentityAuthServices(
   const pool = dependencies.pool ?? createIdentityPool(config.databaseUrl);
   const emailSender =
     dependencies.emailSender ??
-    new ResendEmailOtpSender({
-      apiKey: config.resendApiKey,
-      from: config.resendFrom,
-    });
+    (config.testOtp
+      ? new FakeEmailOtpSender()
+      : new ResendEmailOtpSender({
+          apiKey: config.resendApiKey,
+          from: config.resendFrom,
+        }));
   return {
     pool,
     user: betterAuth(
diff --git a/frontend/src/modules/identity/config.ts b/frontend/src/modules/identity/config.ts
index 2dbb2bb4..4343af18 100644
--- a/frontend/src/modules/identity/config.ts
+++ b/frontend/src/modules/identity/config.ts
@@ -12,6 +12,8 @@ export interface SelfHostedIdentityConfig {
   userSecret: string;
   resendApiKey: string;
   resendFrom: string;
+  /** Fixed OTP accepted when IDENTITY_TEST_OTP is set (test channel only). */
+  testOtp: string | null;
 }
 
 export type IdentityConfig =
@@ -90,6 +92,15 @@ function readSender(env: IdentityEnvironment): string {
   return value;
 }
 
+function readTestOtp(env: IdentityEnvironment): string | null {
+  const value = env.IDENTITY_TEST_OTP?.trim() || "";
+  if (!value) return null;
+  if (!/^\d{6}$/.test(value)) {
+    throw new Error("IDENTITY_TEST_OTP must be a 6-digit code when set");
+  }
+  return value;
+}
+
 export function readSelfHostedIdentityConfig(
   env: IdentityEnvironment,
 ): SelfHostedIdentityConfig {
@@ -108,6 +119,7 @@ export function readSelfHostedIdentityConfig(
     userSecret,
     resendApiKey: required(env, "RESEND_API_KEY"),
     resendFrom: readSender(env),
+    testOtp: readTestOtp(env),
   };
 }
 
diff --git a/frontend/tests/identity-auth-factory.test.ts b/frontend/tests/identity-auth-factory.test.ts
index ed63eacb..a327cdc0 100644
--- a/frontend/tests/identity-auth-factory.test.ts
+++ b/frontend/tests/identity-auth-factory.test.ts
@@ -6,7 +6,7 @@ import { createDatabaseAdminAuthorizer, createIdentityPool } from "../src/module
 import { FakeEmailOtpSender } from "../src/modules/identity/email/fake-email-otp-sender.ts";
 import type { SelfHostedIdentityConfig } from "../src/modules/identity/config.ts";
 
-const config: SelfHostedIdentityConfig = { provider: "self-hosted", databaseUrl: "postgresql://identity_runtime:test-password@postgres:5432/jyotisha", userOrigin: "https://staging.jyotisha.chat", adminOrigin: "https://admin.staging.jyotisha.chat", userSecret: "user-secret-that-is-at-least-32-bytes-long", resendApiKey: "re_test", resendFrom: "Jyotisha <login@staging.jyotisha.chat>" };
+const config: SelfHostedIdentityConfig = { provider: "self-hosted", databaseUrl: "postgresql://identity_runtime:test-password@postgres:5432/jyotisha", userOrigin: "https://staging.jyotisha.chat", adminOrigin: "https://admin.staging.jyotisha.chat", userSecret: "user-secret-that-is-at-least-32-bytes-long", resendApiKey: "re_test", resendFrom: "Jyotisha <login@staging.jyotisha.chat>", testOtp: null };
 const database = { kind: "pool" } as unknown as Pool;
 
 test("Better Auth trusts only the two exact origins and keeps host-only cookies", () => {
@@ -41,6 +41,17 @@ test("OTP policy remains hashed and bounded", async () => {
   assert.match(sender.messages[0].idempotencyKey, /^otp-[0-9a-f]{64}$/);
 });
 
+test("test OTP channel pins a fixed code and never sends a real email", async () => {
+  const sender = new FakeEmailOtpSender();
+  const options = createEmailOtpOptions(sender, config.userSecret, false, "123456");
+  assert.equal(options.generateOTP?.({ email: "tester@example.com", type: "sign-in" }), "123456");
+  const message = sender.messages[0];
+  await options.sendVerificationOTP({ email: "tester@example.com", otp: "123456", type: "sign-in" });
+  assert.equal(sender.messages.length, 1);
+  assert.equal(sender.messages[0].otp, "123456");
+  assert.match(sender.messages[0].idempotencyKey, /^otp-[0-9a-f]{64}$/);
+});
+
 test("identity pool forces the identity search path", async () => {
   const pool = createIdentityPool(config.databaseUrl);
   try { assert.equal(pool.options.options, "-c search_path=identity,pg_catalog"); } finally { await pool.end(); }
diff --git a/frontend/tests/identity-auth-integration.test.ts b/frontend/tests/identity-auth-integration.test.ts
index cebeb0d2..10f7c1e2 100644
--- a/frontend/tests/identity-auth-integration.test.ts
+++ b/frontend/tests/identity-auth-integration.test.ts
@@ -133,6 +133,7 @@ test("Better Auth supports shared user OTP/password sessions for admins", async
     userSecret: "user-secret-that-is-at-least-32-bytes-long",
     resendApiKey: "re_test",
     resendFrom: "Jyotisha <login@staging.jyotisha.chat>",
+    testOtp: null,
   };
   const previousEnv = new Map(
     envKeys.map((key) => [key, process.env[key]] as const),
diff --git a/frontend/tests/identity-config.test.ts b/frontend/tests/identity-config.test.ts
index 64f4f47b..d3246d08 100644
--- a/frontend/tests/identity-config.test.ts
+++ b/frontend/tests/identity-config.test.ts
@@ -60,3 +60,20 @@ test("localhost may use two distinct HTTP origins", () => {
   });
   assert.equal(config.provider, "self-hosted");
 });
+
+test("identity test OTP channel is opt-in and strictly six digits", () => {
+  const without = readIdentityConfig(selfHostedEnvironment);
+  assert.equal(without.provider === "self-hosted" ? without.testOtp : "unexpected", null);
+
+  const withOtp = readIdentityConfig({ ...selfHostedEnvironment, IDENTITY_TEST_OTP: "123456" });
+  assert.equal(withOtp.provider === "self-hosted" ? withOtp.testOtp : null, "123456");
+
+  assert.throws(
+    () => readIdentityConfig({ ...selfHostedEnvironment, IDENTITY_TEST_OTP: "12345" }),
+    /must be a 6-digit/,
+  );
+  assert.throws(
+    () => readIdentityConfig({ ...selfHostedEnvironment, IDENTITY_TEST_OTP: "abcdef" }),
+    /must be a 6-digit/,
+  );
+});
diff --git a/frontend/tests/identity-host-routing.test.ts b/frontend/tests/identity-host-routing.test.ts
index 9634083a..e4983f04 100644
--- a/frontend/tests/identity-host-routing.test.ts
+++ b/frontend/tests/identity-host-routing.test.ts
@@ -11,6 +11,7 @@ const config: SelfHostedIdentityConfig = {
   userSecret: "user-secret-that-is-at-least-32-bytes-long",
   resendApiKey: "re_test",
   resendFrom: "Jyotisha <login@staging.jyotisha.chat>",
+  testOtp: null,
 };
 
 test("identity host accepts only the two configured origins", () => {
diff --git a/frontend/tests/identity-login-provider.test.ts b/frontend/tests/identity-login-provider.test.ts
index 73fab5e3..c6babaa2 100644
--- a/frontend/tests/identity-login-provider.test.ts
+++ b/frontend/tests/identity-login-provider.test.ts
@@ -245,6 +245,21 @@ test("login UI preserves accessible OTP, password, registration, and reset input
   assert.doesNotMatch(component, /hostname\.startsWith|admin\.staging/);
   assert.match(component, /动态验证码/);
   assert.match(component, /恢复码/);
+  assert.match(component, /testOtp\?: string \| null/);
+  assert.match(component, /测试环境：验证码固定为/);
+  assert.match(component, /不会发送真实邮件/);
+
+  const loginPage = readFileSync(
+    new URL("../src/app/login/page.tsx", import.meta.url),
+    "utf8",
+  );
+  assert.match(loginPage, /testOtp=\{config\.provider === "self-hosted" \? config\.testOtp : null\}/);
+
+  const styles = readFileSync(
+    new URL("../src/app/globals.css", import.meta.url),
+    "utf8",
+  );
+  assert.match(styles, /\.auth-test-channel \{[\s\S]*border: 1px dashed/);
 
   const route = readFileSync(
     new URL("../src/app/api/account/password/route.ts", import.meta.url),