diff --git a/apps/pwa/src/App.test.tsx b/apps/pwa/src/App.test.tsx
index 496d4ed..56238ca 100644
--- a/apps/pwa/src/App.test.tsx
+++ b/apps/pwa/src/App.test.tsx
@@ -74,21 +74,33 @@ vi.mock('./routes/ListDetail.js', () => ({
   ListDetail: () => <div data-testid="list-detail">ListDetail</div>,
 }));
 
+vi.mock('./routes/LoginPage.js', () => ({
+  LoginPage: () => <div data-testid="login-page">LoginPage</div>,
+}));
+
 // Mock the API client — this is the key mock for the gate
 vi.mock('./api/client.js', () => ({
   fetchSetupStatus: vi.fn(),
   fetchMe: vi.fn(),
+  // Phase 19: fetchAuthMode is queried in App.tsx for the /login gate
+  fetchAuthMode: vi.fn().mockResolvedValue({ localEnabled: true, oidcEnabled: false }),
   SetupAlreadyLockedError: class SetupAlreadyLockedError extends Error {
     readonly name = 'SetupAlreadyLockedError';
   },
   SessionExpiredError: class SessionExpiredError extends Error {
     readonly name = 'SessionExpiredError';
   },
+  LoginError: class LoginError extends Error {
+    readonly name = 'LoginError';
+    constructor(public readonly code: string) {
+      super(`Login failed: ${code}`);
+    }
+  },
 }));
 
 // ── Imports (after mocks) ────────────────────────────────────────────────────
 
-import { fetchSetupStatus, fetchMe } from './api/client.js';
+import { fetchSetupStatus, fetchMe, fetchAuthMode } from './api/client.js';
 import type { Mock } from 'vitest';
 import App from './App.js';
 
@@ -113,6 +125,7 @@ function renderApp(queryClient: QueryClient) {
 
 const mockFetchSetupStatus = fetchSetupStatus as Mock;
 const mockFetchMe = fetchMe as Mock;
+const _mockFetchAuthMode = fetchAuthMode as Mock; // eslint-disable-line @typescript-eslint/no-unused-vars
 
 // ── Tests ─────────────────────────────────────────────────────────────────────
 
@@ -129,6 +142,7 @@ describe('App — setup-status gate', () => {
         color: '#4a90d9',
         isAdmin: false,
         needsProviderSetup: false,
+        hasLocalCredential: false,
       },
     });
   });
diff --git a/apps/pwa/src/App.tsx b/apps/pwa/src/App.tsx
index b641ea5..bfa9ddf 100644
--- a/apps/pwa/src/App.tsx
+++ b/apps/pwa/src/App.tsx
@@ -52,18 +52,33 @@ import { ListsIndex } from './routes/ListsIndex.js';
 import { ListDetail } from './routes/ListDetail.js';
 import { AdminPage } from './routes/AdminPage.js';
 import { SetupPage } from './routes/SetupPage.js';
+import { LoginPage } from './routes/LoginPage.js';
 import { BottomTabBar } from './components/BottomTabBar.js';
 import { AppNav } from './components/AppNav.js';
 import { PushPermissionPrompt } from './components/PushPermissionPrompt.js';
 import { PermissionDeniedBanner } from './components/PermissionDeniedBanner.js';
 import { SetupBanner } from './components/SetupBanner.js';
 import { SettingsSheet } from './components/SettingsSheet.js';
-import { fetchMe, fetchSetupStatus } from './api/client.js';
+import { fetchMe, fetchSetupStatus, fetchAuthMode } from './api/client.js';
 
 function isPhone(): boolean {
   return typeof window !== 'undefined' && window.matchMedia('(max-width: 767px)').matches;
 }
 
+/**
+ * OidcRedirect — tiny helper that triggers a top-level navigation to /api/login.
+ *
+ * Used in the auth gate when localEnabled === false and oidcEnabled === true —
+ * the OIDC-only mode that was the app's only auth path before Phase 19.
+ * A top-level navigation (not a React Router navigate) is required because
+ * /api/login responds with a 302 redirect to the external OIDC provider,
+ * which browsers cannot follow as a fetch/XHR (T-07-04).
+ */
+function OidcRedirect() {
+  window.location.replace('/api/login');
+  return <div aria-hidden="true" />;
+}
+
 export default function App() {
   const [settingsOpen, setSettingsOpen] = useState(false);
   const phone = isPhone();
@@ -98,6 +113,16 @@ export default function App() {
     staleTime: 0,
   });
 
+  // Auth mode query — fetched pre-auth (no session required).
+  // Determines whether to show /login (localEnabled) or OIDC redirect (!localEnabled && oidcEnabled).
+  // staleTime 60s: auth mode changes rarely; re-fetches on new tab/focus.
+  const authModeQuery = useQuery({
+    queryKey: ['authMode'],
+    queryFn: fetchAuthMode,
+    retry: false,
+    staleTime: 60_000,
+  });
+
   // isAdmin from /api/me — used for UX gating only (D-03). Server enforces 403.
   // While meQuery is loading, isAdmin is false/undefined → admin route redirects
   // (loading gate: no flash of admin content for non-admins).
@@ -166,6 +191,15 @@ export default function App() {
           }
         />
 
+        {/* /login route — standalone login page, no AppNav/BottomTabBar shell (UI-SPEC §Surface 1).
+            Phase 19: shown when the user is unauthenticated AND localEnabled === true.
+            The route itself always renders LoginPage (authMode gating is in the `*` route gate below).
+            LoginPage receives authMode so it can show the optional OIDC button when oidcEnabled. */}
+        <Route
+          path="/login"
+          element={<LoginPage authMode={authModeQuery.data} />}
+        />
+
         {/* All other routes are gated on setup completion */}
         <Route
           path="*"
@@ -176,6 +210,13 @@ export default function App() {
             ) : setupComplete === false ? (
               // Not configured: full-app redirect to /setup (no nav shell rendered)
               <Navigate to="/setup" replace />
+            ) : meQuery.isError && !meQuery.isLoading && authModeQuery.data?.localEnabled ? (
+              // Unauthenticated + localEnabled: redirect to /login
+              <Navigate to="/login" replace />
+            ) : meQuery.isError && !meQuery.isLoading && !authModeQuery.data?.localEnabled && authModeQuery.data?.oidcEnabled ? (
+              // Unauthenticated + OIDC-only mode: top-level redirect to /api/login (today's behavior)
+              // Use a render side-effect via useEffect isn't available here; use a helper element
+              <OidcRedirect />
             ) : (
               // Setup complete: render the normal authenticated app shell
               <>
diff --git a/apps/pwa/src/routes/LoginPage.tsx b/apps/pwa/src/routes/LoginPage.tsx
new file mode 100644
index 0000000..22f3807
--- /dev/null
+++ b/apps/pwa/src/routes/LoginPage.tsx
@@ -0,0 +1,465 @@
+/**
+ * LoginPage — standalone /login route (Phase 19, D-04).
+ *
+ * UI-SPEC §Surface Architecture Surfaces 1–10:
+ *   Surface 1: Full-page standalone route (no AppNav/BottomTabBar/SetupBanner)
+ *   Surface 2: BrandSlot — app logo placeholder + name + tagline (Phase 17 seam)
+ *   Surface 3: Login card — "Sign in" heading
+ *   Surface 4: Username field (id="login-username", spellCheck/autoCapitalize/autoCorrect off)
+ *   Surface 5: Password field with show/hide toggle (Eye/EyeOff, 44px tap target)
+ *   Surface 6: Error/lockout banner (role="status", aria-live="polite", 4 error variants)
+ *   Surface 7: Primary "Sign in" / "Signing in…" submit button (full-width)
+ *   Surface 8: Method divider ("or") — rendered only when oidcEnabled
+ *   Surface 9: "Login with OIDC" outlined button — rendered only when oidcEnabled
+ *   Surface 10: "Forgot your password? Ask your admin." helper (informational only)
+ *
+ * Auth gate: App.tsx renders this route when meQuery returns 401 AND localEnabled.
+ * On success: window.location.replace('/') — the cookie is set by the API server.
+ *
+ * Security:
+ *   T-19-18: password field is controlled state only; never written to localStorage/sessionStorage
+ *   T-19-19: single shared "Incorrect username or password." — no field-level blame
+ *   T-19-20: plain-text JSX children; no dangerouslySetInnerHTML (T-05-24)
+ *   T-19-21: D-06 — UI never renders the provider name; uses generic "Login with OIDC"
+ */
+
+import { useState, useRef, useEffect } from 'react';
+import { useMutation } from '@tanstack/react-query';
+import { AlertCircle, Eye, EyeOff, Loader2, ShieldCheck } from 'lucide-react';
+import { fetchLocalLogin, LoginError } from '../api/client.js';
+import { BrandSlot } from '../components/BrandSlot.js';
+
+// ── Types ─────────────────────────────────────────────────────────────────────
+
+export interface LoginPageProps {
+  authMode?: { localEnabled: boolean; oidcEnabled: boolean };
+}
+
+// ── Styles (copied from SetupPage.tsx — UI-SPEC §Design System) ───────────────
+
+const pageStyle: React.CSSProperties = {
+  minHeight: '100dvh',
+  display: 'flex',
+  flexDirection: 'column',
+  alignItems: 'center',
+  justifyContent: 'flex-start',
+  background: 'var(--color-surface, #ffffff)',
+  fontFamily: 'var(--font-family-base)',
+  color: 'var(--color-text-primary, #111318)',
+};
+
+const contentColStyle: React.CSSProperties = {
+  maxWidth: '400px', // login card is narrower than setup wizard (UI-SPEC Surface 1)
+  width: '100%',
+  margin: '0 auto',
+  padding: 'var(--space-12, 48px) var(--space-6, 24px)',
+};
+
+const cardStyle: React.CSSProperties = {
+  background: 'var(--color-surface, #ffffff)',
+  border: '1px solid var(--color-border, #e2e4e9)',
+  borderRadius: '8px',
+  padding: 'var(--space-6, 24px)',
+  boxShadow: '0 1px 4px rgba(0,0,0,0.06)',
+};
+
+const primaryBtnStyle = (disabled: boolean): React.CSSProperties => ({
+  background: disabled ? 'var(--color-border, #e2e4e9)' : 'var(--color-member-0, #4a90d9)',
+  color: '#ffffff',
+  border: 'none',
+  cursor: disabled ? 'default' : 'pointer',
+  fontSize: 'var(--text-label-size, 13px)',
+  fontWeight: 600,
+  minHeight: '44px',
+  minWidth: '44px',
+  width: '100%',
+  padding: '0 var(--space-6, 24px)',
+  borderRadius: 'var(--space-1, 4px)',
+  fontFamily: 'var(--font-family-base)',
+  transition: 'background 0.15s ease',
+  display: 'flex',
+  alignItems: 'center',
+  justifyContent: 'center',
+  gap: 'var(--space-2, 8px)',
+});
+
+const inputStyle = (hasError: boolean): React.CSSProperties => ({
+  width: '100%',
+  boxSizing: 'border-box',
+  padding: 'var(--space-3, 12px) var(--space-4, 16px)',
+  border: `1px solid ${hasError ? 'var(--color-destructive, #dc2626)' : 'var(--color-border, #e2e4e9)'}`,
+  borderRadius: 'var(--space-1, 4px)',
+  fontSize: 'var(--text-body-size, 15px)',
+  color: 'var(--color-text-primary, #111318)',
+  background: 'var(--color-surface, #ffffff)',
+  fontFamily: 'var(--font-family-base)',
+  outline: 'none',
+});
+
+const labelStyle: React.CSSProperties = {
+  display: 'block',
+  fontSize: 'var(--text-label-size, 13px)',
+  fontWeight: 600,
+  color: 'var(--color-text-primary, #111318)',
+  marginBottom: 'var(--space-1, 4px)',
+};
+
+// ── LoginPage ─────────────────────────────────────────────────────────────────
+
+export function LoginPage({ authMode }: LoginPageProps) {
+  const [username, setUsername] = useState('');
+  const [password, setPassword] = useState('');
+  const [showPassword, setShowPassword] = useState(false);
+  const [loginError, setLoginError] = useState<
+    'invalid' | 'rate-limit' | 'locked' | 'server' | null
+  >(null);
+
+  // Ref for moving focus to the error heading on error (UI-SPEC §Focus Management)
+  const errorHeadingRef = useRef<HTMLDivElement>(null);
+  // Ref for password field so Enter in username moves focus there
+  const passwordRef = useRef<HTMLInputElement>(null);
+
+  const oidcEnabled = authMode?.oidcEnabled ?? false;
+
+  // Move focus to error banner heading when error state activates
+  useEffect(() => {
+    if (loginError && errorHeadingRef.current) {
+      errorHeadingRef.current.focus();
+    }
+  }, [loginError]);
+
+  const loginMutation = useMutation({
+    mutationFn: () => fetchLocalLogin({ username, password }),
+    onSuccess: () => {
+      // Cookie is set by the API; replace to clear the /login URL from history
+      window.location.replace('/');
+    },
+    onError: (err) => {
+      if (err instanceof LoginError) {
+        setLoginError(err.code);
+      } else {
+        setLoginError('server');
+      }
+    },
+  });
+
+  const isLoading = loginMutation.isPending;
+  const bothNonEmpty = username.trim().length > 0 && password.length > 0;
+  const submitDisabled =
+    isLoading ||
+    !bothNonEmpty ||
+    loginError === 'rate-limit' ||
+    loginError === 'locked';
+
+  // Derive whether inputs should show error state
+  const inputHasError = loginError === 'invalid';
+
+  function handleSubmit() {
+    if (submitDisabled) return;
+    setLoginError(null);
+    loginMutation.mutate();
+  }
+
+  function handleUsernameKeyDown(e: React.KeyboardEvent<HTMLInputElement>) {
+    if (e.key === 'Enter') {
+      e.preventDefault();
+      passwordRef.current?.focus();
+    }
+  }
+
+  function handlePasswordKeyDown(e: React.KeyboardEvent<HTMLInputElement>) {
+    if (e.key === 'Enter') {
+      e.preventDefault();
+      handleSubmit();
+    }
+  }
+
+  return (
+    <div style={pageStyle}>
+      <div style={contentColStyle} role="main">
+        {/* Surface 2 — Brand Slot (above the login card, in the flow) */}
+        <BrandSlot />
+
+        {/* Surface 3 — Login Card */}
+        <div style={cardStyle}>
+          <h2
+            style={{
+              margin: '0 0 var(--space-6, 24px) 0',
+              fontSize: 'var(--text-heading-size, 18px)',
+              fontWeight: 600,
+              lineHeight: 'var(--text-heading-line-height, 1.25)',
+              color: 'var(--color-text-primary, #111318)',
+            }}
+          >
+            Sign in
+          </h2>
+
+          {/* Surface 4 — Username field */}
+          <div style={{ marginBottom: 'var(--space-4, 16px)' }}>
+            <label htmlFor="login-username" style={labelStyle}>
+              Username
+            </label>
+            <input
+              id="login-username"
+              type="text"
+              autoFocus
+              autoComplete="username"
+              spellCheck={false}
+              autoCapitalize="none"
+              autoCorrect="off"
+              value={username}
+              onChange={(e) => setUsername(e.target.value)}
+              onKeyDown={handleUsernameKeyDown}
+              aria-describedby={loginError ? 'login-error' : undefined}
+              style={inputStyle(inputHasError)}
+            />
+          </div>
+
+          {/* Surface 5 — Password field with show/hide toggle */}
+          <div style={{ marginBottom: 'var(--space-4, 16px)' }}>
+            <label htmlFor="login-password" style={labelStyle}>
+              Password
+            </label>
+            <div style={{ position: 'relative' }}>
+              <input
+                id="login-password"
+                ref={passwordRef}
+                type={showPassword ? 'text' : 'password'}
+                autoComplete="current-password"
+                value={password}
+                onChange={(e) => setPassword(e.target.value)}
+                onKeyDown={handlePasswordKeyDown}
+                onBlur={() => setShowPassword(false)}
+                aria-describedby={loginError ? 'login-error' : undefined}
+                style={{ ...inputStyle(inputHasError), paddingRight: '44px' }}
+              />
+              {/* Show/hide toggle button — 44px tap target (UI-SPEC Surface 5) */}
+              <button
+                type="button"
+                aria-label={showPassword ? 'Hide password' : 'Show password'}
+                aria-pressed={showPassword}
+                onClick={() => setShowPassword((v) => !v)}
+                style={{
+                  position: 'absolute',
+                  right: 0,
+                  top: 0,
+                  height: '100%',
+                  minWidth: '44px',
+                  background: 'none',
+                  border: 'none',
+                  cursor: 'pointer',
+                  color: 'var(--color-text-muted, #9ca3af)',
+                  display: 'flex',
+                  alignItems: 'center',
+                  justifyContent: 'center',
+                  padding: 0,
+                }}
+              >
+                {showPassword ? (
+                  <EyeOff size={16} aria-hidden="true" />
+                ) : (
+                  <Eye size={16} aria-hidden="true" />
+                )}
+              </button>
+            </div>
+          </div>
+
+          {/* Surface 6 — Error / lockout banner */}
+          {loginError && (
+            <div
+              id="login-error"
+              role="status"
+              aria-live="polite"
+              aria-atomic="true"
+              style={{ marginBottom: 'var(--space-4, 16px)' }}
+            >
+              {loginError === 'invalid' && (
+                <div
+                  ref={errorHeadingRef}
+                  tabIndex={-1}
+                  style={{
+                    display: 'flex',
+                    alignItems: 'center',
+                    gap: 'var(--space-2, 8px)',
+                    fontSize: 'var(--text-body-size, 15px)',
+                    fontWeight: 400,
+                    color: 'var(--color-destructive, #dc2626)',
+                    outline: 'none',
+                  }}
+                >
+                  <AlertCircle size={16} aria-hidden="true" style={{ flexShrink: 0 }} />
+                  Incorrect username or password.
+                </div>
+              )}
+
+              {loginError === 'rate-limit' && (
+                <div
+                  ref={errorHeadingRef}
+                  tabIndex={-1}
+                  style={{
+                    display: 'flex',
+                    alignItems: 'center',
+                    gap: 'var(--space-2, 8px)',
+                    background: 'var(--color-surface-dim, #f7f7f8)',
+                    borderRadius: 'var(--space-1, 4px)',
+                    padding: 'var(--space-3, 12px) var(--space-4, 16px)',
+                    fontSize: 'var(--text-label-size, 13px)',
+                    fontWeight: 400,
+                    color: 'var(--color-destructive, #dc2626)',
+                    outline: 'none',
+                  }}
+                >
+                  <AlertCircle size={16} aria-hidden="true" style={{ flexShrink: 0 }} />
+                  Too many attempts. Please wait a moment and try again.
+                </div>
+              )}
+
+              {loginError === 'locked' && (
+                <div
+                  ref={errorHeadingRef}
+                  tabIndex={-1}
+                  style={{
+                    display: 'flex',
+                    alignItems: 'center',
+                    gap: 'var(--space-2, 8px)',
+                    background: 'var(--color-surface-dim, #f7f7f8)',
+                    borderRadius: 'var(--space-1, 4px)',
+                    padding: 'var(--space-3, 12px) var(--space-4, 16px)',
+                    fontSize: 'var(--text-label-size, 13px)',
+                    fontWeight: 400,
+                    color: 'var(--color-destructive, #dc2626)',
+                    outline: 'none',
+                  }}
+                >
+                  <AlertCircle size={16} aria-hidden="true" style={{ flexShrink: 0 }} />
+                  This account is temporarily locked. Contact your admin to reset access.
+                </div>
+              )}
+
+              {loginError === 'server' && (
+                <div
+                  ref={errorHeadingRef}
+                  tabIndex={-1}
+                  style={{
+                    display: 'flex',
+                    alignItems: 'center',
+                    gap: 'var(--space-2, 8px)',
+                    fontSize: 'var(--text-body-size, 15px)',
+                    fontWeight: 400,
+                    color: 'var(--color-destructive, #dc2626)',
+                    outline: 'none',
+                  }}
+                >
+                  <AlertCircle size={16} aria-hidden="true" style={{ flexShrink: 0 }} />
+                  Something went wrong. Please try again.
+                </div>
+              )}
+            </div>
+          )}
+
+          {/* Surface 7 — Primary submit button */}
+          <button
+            type="button"
+            onClick={handleSubmit}
+            disabled={submitDisabled}
+            style={primaryBtnStyle(submitDisabled)}
+          >
+            {isLoading && (
+              <Loader2
+                size={16}
+                aria-hidden="true"
+                style={{ animation: 'spin 1s linear infinite', flexShrink: 0 }}
+              />
+            )}
+            {isLoading ? 'Signing in…' : 'Sign in'}
+          </button>
+
+          {/* Surface 10 — Forgot password helper (informational only, not interactive) */}
+          <p
+            style={{
+              margin: 0,
+              marginTop: 'var(--space-4, 16px)',
+              fontSize: 'var(--text-label-size, 13px)',
+              fontWeight: 400,
+              color: 'var(--color-text-secondary, #6b7280)',
+              textAlign: 'center',
+              lineHeight: 'var(--text-label-line-height, 1.4)',
+            }}
+          >
+            Forgot your password? Ask your admin.
+          </p>
+        </div>
+
+        {/* Surfaces 8 & 9 — Method divider + OIDC button (only when oidcEnabled) */}
+        {oidcEnabled && (
+          <>
+            {/* Surface 8 — Method divider */}
+            <div
+              aria-hidden="true"
+              style={{
+                display: 'flex',
+                alignItems: 'center',
+                gap: 'var(--space-3, 12px)',
+                marginTop: 'var(--space-4, 16px)',
+                marginBottom: 'var(--space-4, 16px)',
+              }}
+            >
+              <div
+                style={{
+                  flex: 1,
+                  height: '1px',
+                  background: 'var(--color-border, #e2e4e9)',
+                }}
+              />
+              <span
+                style={{
+                  fontSize: 'var(--text-label-size, 13px)',
+                  fontWeight: 400,
+                  color: 'var(--color-text-secondary, #6b7280)',
+                  flexShrink: 0,
+                }}
+              >
+                or
+              </span>
+              <div
+                style={{
+                  flex: 1,
+                  height: '1px',
+                  background: 'var(--color-border, #e2e4e9)',
+                }}
+              />
+            </div>
+
+            {/* Surface 9 — OIDC login button — uses generic copy per D-06 */}
+            <button
+              type="button"
+              onClick={() => {
+                // Initiate OIDC authorization-code flow (same redirect as today's OIDC-only mode)
+                window.location.href = '/api/login';
+              }}
+              style={{
+                width: '100%',
+                minHeight: '44px',
+                background: 'transparent',
+                border: '1px solid var(--color-member-0, #4a90d9)',
+                color: 'var(--color-member-0, #4a90d9)',
+                borderRadius: 'var(--space-1, 4px)',
+                cursor: 'pointer',
+                fontSize: 'var(--text-label-size, 13px)',
+                fontWeight: 600,
+                fontFamily: 'var(--font-family-base)',
+                display: 'flex',
+                alignItems: 'center',
+                justifyContent: 'center',
+                gap: 'var(--space-2, 8px)',
+              }}
+            >
+              <ShieldCheck size={16} aria-hidden="true" />
+              Login with OIDC
+            </button>
+          </>
+        )}
+      </div>
+    </div>
+  );
+}