diff --git a/vehicle-data-platform/apps/web/src/v2/auth/AuthGate.test.tsx b/vehicle-data-platform/apps/web/src/v2/auth/AuthGate.test.tsx
index ccdf763b..5de34bcc 100644
--- a/vehicle-data-platform/apps/web/src/v2/auth/AuthGate.test.tsx
+++ b/vehicle-data-platform/apps/web/src/v2/auth/AuthGate.test.tsx
@@ -42,7 +42,7 @@ test('uses a branded Semi UI session state while restoring authentication', () =
 
 test('presents failed credentials as a clear Semi UI alert without losing the login form', async () => {
   mocks.session.mockRejectedValue(new Error('未登录'));
-  mocks.login.mockRejectedValue(new Error('账号或密码错误'));
+  mocks.login.mockRejectedValue(new Error('账号或密码错误 (traceId: trace-login-test)'));
   const client = new QueryClient({ defaultOptions: { queries: { retry: false } } });
 
   const view = render(<QueryClientProvider client={client}><AuthGate><div>受保护工作台</div></AuthGate></QueryClientProvider>);
@@ -52,6 +52,9 @@ test('presents failed credentials as a clear Semi UI alert without losing the lo
 
   expect(await screen.findByRole('alert')).toHaveTextContent('登录未完成');
   expect(screen.getByRole('alert')).toHaveTextContent('账号或密码错误');
+  expect(screen.getByRole('alert')).toHaveTextContent('请确认账号和密码后重试');
+  expect(screen.getByRole('alert')).not.toHaveTextContent('trace-login-test');
+  expect(view.container.querySelector('.v2-auth-error')).toHaveAttribute('data-support-trace', 'trace-login-test');
   expect(view.container.querySelector('.v2-auth-error .semi-banner')).toBeInTheDocument();
   expect(screen.getByPlaceholderText('请输入用户名')).toBeInTheDocument();
 });
diff --git a/vehicle-data-platform/apps/web/src/v2/auth/AuthGate.tsx b/vehicle-data-platform/apps/web/src/v2/auth/AuthGate.tsx
index 41baaad0..5fb5ed9e 100644
--- a/vehicle-data-platform/apps/web/src/v2/auth/AuthGate.tsx
+++ b/vehicle-data-platform/apps/web/src/v2/auth/AuthGate.tsx
@@ -7,6 +7,7 @@ import { PasswordInput } from '../shared/PasswordInput';
 import { clearAccessToken, getAccessToken, PLATFORM_UNAUTHORIZED_EVENT, PlatformSession, setAccessToken } from './session';
 
 const { Title, Text } = Typography;
+const TRACE_ID_SUFFIX = /\s*\(traceId:\s*([^)]+)\)\s*$/i;
 
 type AuthContextValue = {
   session: PlatformSession;
@@ -55,15 +56,24 @@ function AuthLoadingState() {
   </main>;
 }
 
+function authErrorPresentation(message: string) {
+  const match = message.match(TRACE_ID_SUFFIX);
+  return {
+    message: message.replace(TRACE_ID_SUFFIX, '').trim() || '登录失败，请稍后重试',
+    traceId: match?.[1]?.trim() ?? ''
+  };
+}
+
 function AuthErrorMessage({ message }: { message: string }) {
-  return <div className="v2-auth-error">
+  const presentation = authErrorPresentation(message);
+  return <div className="v2-auth-error" data-support-trace={presentation.traceId || undefined}>
     <Banner
       type="danger"
       bordered
       closeIcon={null}
       icon={<IconAlertTriangle />}
       title="登录未完成"
-      description={message}
+      description={<span><strong>{presentation.message}</strong><small>请确认账号和密码后重试；连续失败可能会临时锁定账号。</small></span>}
     />
   </div>;
 }
diff --git a/vehicle-data-platform/apps/web/src/v2/styles/workspace.css b/vehicle-data-platform/apps/web/src/v2/styles/workspace.css
index 7b099ad7..7ef4de90 100644
--- a/vehicle-data-platform/apps/web/src/v2/styles/workspace.css
+++ b/vehicle-data-platform/apps/web/src/v2/styles/workspace.css
@@ -5853,6 +5853,12 @@
 .v2-auth-form-heading {
   display: grid;
   justify-items: center;
+  margin: -32px -34px 0;
+  border-bottom: 1px solid #e4ebf4;
+  background:
+    radial-gradient(circle at 50% -38%, rgba(18, 104, 243, .15), transparent 62%),
+    linear-gradient(180deg, #fbfdff 0%, #f7faff 100%);
+  padding: 30px 34px 24px;
 }
 
 .v2-auth-form-heading > h3.semi-typography {
@@ -5888,10 +5894,18 @@
   color: #d92d20;
 }
 
+.v2-auth-error .semi-banner-content-body {
+  display: grid;
+  min-width: 0;
+  flex: 1 1 auto;
+  gap: 3px;
+}
+
 .v2-auth-error .semi-banner-title {
   color: #9f2d25;
   font-size: 11px;
   font-weight: 700;
+  white-space: nowrap;
 }
 
 .v2-auth-error .semi-banner-description {
@@ -5901,6 +5915,24 @@
   line-height: 1.5;
 }
 
+.v2-auth-error .semi-banner-description > span {
+  display: grid;
+  gap: 3px;
+}
+
+.v2-auth-error .semi-banner-description strong {
+  color: #a13d35;
+  font-size: 11px;
+  font-weight: 650;
+  line-height: 1.45;
+}
+
+.v2-auth-error .semi-banner-description small {
+  color: #b26861;
+  font-size: 9px;
+  line-height: 1.5;
+}
+
 .v2-auth-form > .v2-auth-error + .semi-button-primary {
   margin-top: 16px;
 }
@@ -5931,6 +5963,7 @@
 .v2-auth-screen:not(.is-session-loading) {
   grid-template-columns: minmax(430px, 1.12fr) minmax(420px, 460px);
   column-gap: clamp(34px, 5vw, 82px);
+  justify-content: center;
   background:
     radial-gradient(circle at 18% 14%, rgba(18, 104, 243, .11), transparent 30%),
     linear-gradient(135deg, #f7faff 0%, #f2f6fb 56%, #eef3f9 100%);
@@ -6062,8 +6095,9 @@
 .v2-auth-screen:not(.is-session-loading) > .v2-auth-card.semi-card {
   width: min(460px, 100%);
   justify-self: end;
+  overflow: hidden;
   border-color: rgba(207, 219, 234, .96);
-  border-radius: 24px;
+  border-radius: 22px;
   background: rgba(255, 255, 255, .98);
   box-shadow: 0 28px 78px rgba(25, 43, 69, .14);
 }
@@ -6098,7 +6132,7 @@
 }
 
 .v2-auth-form > .v2-auth-fields {
-  margin-top: 20px;
+  margin-top: 22px;
 }
 
 .v2-auth-fields {
@@ -6113,18 +6147,22 @@
   gap: 7px;
   margin-top: 14px;
   color: #405269;
-  font-size: 12px;
+  font-size: 13px;
   font-weight: 680;
 }
 
 .v2-auth-fields > label .semi-input-wrapper {
-  height: 44px;
+  height: 48px;
   border-color: #dbe4ef;
   border-radius: 10px;
   background: #fbfcfe;
   box-shadow: none;
 }
 
+.v2-auth-fields > label .semi-input {
+  font-size: 14px;
+}
+
 .v2-auth-fields > label .semi-input-wrapper:hover {
   border-color: #b8c9dd;
   background: #fff;
@@ -6137,16 +6175,20 @@
 }
 
 .v2-auth-form > .semi-button-primary {
-  height: 46px;
+  height: 48px;
   margin-top: 18px;
   border-radius: 10px;
-  font-size: 13px;
+  font-size: 14px;
   font-weight: 750;
   box-shadow: 0 10px 22px rgba(18, 104, 243, .2);
 }
 
 .v2-auth-trust-note {
-  margin-top: 12px;
+  min-height: 48px;
+  margin: 16px -34px -28px;
+  border-top: 1px solid #e8eef5;
+  background: #fbfcfe;
+  padding: 11px 34px;
 }
 
 .v2-auth-trust-note > .semi-typography {
@@ -6285,8 +6327,12 @@
 
 @media (max-width: 680px) {
   .v2-auth-screen:not(.is-session-loading) {
-    display: block;
+    display: grid;
+    width: 100%;
     min-height: 100dvh;
+    grid-template-columns: minmax(0, 1fr);
+    place-items: center;
+    overflow: auto;
     background:
       radial-gradient(circle at 50% 0, rgba(18, 104, 243, .1), transparent 34%),
       #f3f6fa;
@@ -6305,6 +6351,11 @@
     padding: 24px 18px 20px;
   }
 
+  .v2-auth-form-heading {
+    margin: -24px -18px 0;
+    padding: 24px 18px 20px;
+  }
+
   .v2-auth-logo {
     width: 132px;
     margin-bottom: 14px;
@@ -6371,16 +6422,21 @@
   }
 
   .v2-auth-fields > label {
-    font-size: 12px;
+    font-size: 13px;
   }
 
   .v2-auth-fields > label .semi-input-wrapper {
-    height: 46px;
+    height: 48px;
   }
 
   .v2-auth-form > .semi-button-primary {
-    height: 46px;
-    font-size: 13px;
+    height: 48px;
+    font-size: 14px;
+  }
+
+  .v2-auth-trust-note {
+    margin: 14px -18px -20px;
+    padding: 10px 18px;
   }
 
   .v2-route-error > .v2-route-error-card.semi-card {