diff --git a/tests/test_ui.py b/tests/test_ui.py
new file mode 100644
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--- /dev/null
+++ b/tests/test_ui.py
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+"""Web UI tests — page structure, forms, visibility, i18n."""
+
+import pytest
+
+from models import (
+    generate_public_token,
+    get_household_by_name,
+    get_user_by_username,
+    set_public_enabled,
+)
+
+
+# ═══════════════════════════════════════════════════════════════════════════════
+#  Login page
+# ═══════════════════════════════════════════════════════════════════════════════
+
+class TestLoginUI:
+
+    def test_form_has_fields(self, client):
+        resp = client.get("/login")
+        assert resp.status_code == 200
+        html = resp.data.decode()
+        assert 'name="username"' in html
+        assert 'name="password"' in html
+        assert 'type="submit"' in html
+
+    def test_error_on_empty_submit(self, client):
+        resp = client.post("/login", data={}, follow_redirects=True)
+        assert resp.status_code == 200
+        assert b"required" in resp.data.lower()
+
+    def test_error_on_wrong_password(self, client):
+        client.post("/register", data={
+            "username": "ui_user", "password": "correct",
+            "confirm": "correct",
+            "household_action": "create",
+            "new_household_name": "UI House",
+        })
+        client.get("/logout")
+        resp = client.post("/login", data={
+            "username": "ui_user", "password": "wrong",
+        }, follow_redirects=True)
+        assert b"Invalid username or password" in resp.data
+
+    def test_successful_login_redirects_to_dashboard(self, client):
+        client.post("/register", data={
+            "username": "ui_user2", "password": "secret",
+            "confirm": "secret",
+            "household_action": "create",
+            "new_household_name": "UI House 2",
+        })
+        client.get("/logout")
+        resp = client.post("/login", data={
+            "username": "ui_user2", "password": "secret",
+        }, follow_redirects=True)
+        assert resp.status_code == 200
+        assert b"Today" in resp.data or b"Meal" in resp.data
+
+
+# ═══════════════════════════════════════════════════════════════════════════════
+#  Register page
+# ═══════════════════════════════════════════════════════════════════════════════
+
+class TestRegisterUI:
+
+    def test_form_shows_join_create_options(self, client):
+        resp = client.get("/register")
+        html = resp.data.decode()
+        assert 'household_action' in html
+        assert 'new_household_name' in html
+        assert 'household_id' in html
+
+    def test_create_household_makes_admin(self, client):
+        client.post("/register", data={
+            "username": "creator_ui", "password": "pass1234",
+            "confirm": "pass1234",
+            "household_action": "create",
+            "new_household_name": "Creator House",
+        }, follow_redirects=True)
+        user = get_user_by_username("creator_ui")
+        assert user is not None
+        assert user["is_admin"] == 1
+
+    def test_join_household_is_not_admin(self, client):
+        # First user creates household
+        client.post("/register", data={
+            "username": "founder", "password": "founder1",
+            "confirm": "founder1",
+            "household_action": "create",
+            "new_household_name": "Shared Home",
+        })
+        client.get("/logout")
+        # Second user joins
+        hh = get_household_by_name("Shared Home")
+        client.post("/register", data={
+            "username": "member", "password": "member1",
+            "confirm": "member1",
+            "household_action": "join",
+            "household_id": str(hh["id"]),
+        }, follow_redirects=True)
+        member = get_user_by_username("member")
+        assert member["is_admin"] == 0
+
+    def test_duplicate_household_name_error(self, client):
+        client.post("/register", data={
+            "username": "u1", "password": "pass1234",
+            "confirm": "pass1234",
+            "household_action": "create",
+            "new_household_name": "DupHouse",
+        })
+        client.get("/logout")
+        resp = client.post("/register", data={
+            "username": "u2", "password": "pass5678",
+            "confirm": "pass5678",
+            "household_action": "create",
+            "new_household_name": "DupHouse",
+        }, follow_redirects=True)
+        assert b"already exists" in resp.data
+
+    def test_missing_household_selection_error(self, client):
+        resp = client.post("/register", data={
+            "username": "u3", "password": "pass1234",
+            "confirm": "pass1234",
+            "household_action": "join",
+            "household_id": "",
+        }, follow_redirects=True)
+        assert b"select a household" in resp.data.lower()
+
+    def test_password_mismatch_error(self, client):
+        resp = client.post("/register", data={
+            "username": "u4", "password": "abc12345",
+            "confirm": "abc12346",
+            "household_action": "create",
+            "new_household_name": "Mismatch",
+        }, follow_redirects=True)
+        assert b"do not match" in resp.data.lower()
+
+
+# ═══════════════════════════════════════════════════════════════════════════════
+#  Dashboard page
+# ═══════════════════════════════════════════════════════════════════════════════
+
+class TestDashboardUI:
+
+    def test_table_has_correct_columns(self, auth_client):
+        resp = auth_client.get("/dashboard")
+        html = resp.data.decode()
+        assert "User" in html or "Utilisateur" in html or "Benutzer" in html
+        assert "Lunch" in html or "Déjeuner" in html or "Mittagessen" in html
+        assert "Dinner" in html or "Dîner" in html or "Abendessen" in html
+
+    def test_own_user_has_response_buttons(self, auth_client):
+        """Bob (logged in) should see clickable Home/Out buttons for himself."""
+        resp = auth_client.get("/dashboard")
+        html = resp.data.decode()
+        assert 'name="status"' in html
+        assert 'Home' in html or 'Présent' in html or 'Zuhause' in html
+
+    def test_other_users_show_as_badges(self, auth_client):
+        """Alice's status should be a static badge, not a form button."""
+        # Bob answers something first to populate
+        auth_client.post("/respond", data={"meal_type": "lunch", "status": "yes"})
+        resp = auth_client.get("/dashboard")
+        html = resp.data.decode()
+        # Alice's row should have a badge (read-only), Bob's has buttons
+        assert 'badge' in html
+
+    def test_date_nav_links_present(self, auth_client):
+        resp = auth_client.get("/dashboard")
+        html = resp.data.decode()
+        assert "Prev" in html or "Préc" in html or "Zurück" in html
+        assert "Next" in html or "Suiv" in html or "Weiter" in html
+        assert "Today" in html or "Aujourd" in html or "Heute" in html
+
+    def test_changed_mind_badge_appears_after_flip(self, auth_client):
+        """After flipping yes→no, a changed-mind indicator should render."""
+        auth_client.post("/respond", data={"meal_type": "lunch", "status": "yes"})
+        auth_client.post("/respond", data={"meal_type": "lunch", "status": "no"})
+        resp = auth_client.get("/dashboard")
+        # The changed-mind CSS class or the ↻ symbol
+        assert b"changed-mind" in resp.data or b"\\xe2\\x86\\xbb" in resp.data or b"changed" in resp.data.lower()
+
+    def test_history_mode_flag(self, auth_client):
+        """History page should have the history_mode flag / different heading."""
+        resp = auth_client.get("/history")
+        html = resp.data.decode()
+        assert "History" in html or "Historique" in html or "Verlauf" in html
+
+
+# ═══════════════════════════════════════════════════════════════════════════════
+#  Account settings page (password change, delete)
+# ═══════════════════════════════════════════════════════════════════════════════
+
+class TestAccountSettingsUI:
+
+    def test_account_section_visible(self, auth_client):
+        resp = auth_client.get("/dashboard")
+        html = resp.data.decode()
+        assert "Account Settings" in html or "Paramètres du compte" in html or "Kontoeinstellungen" in html
+
+    def test_change_password_form_present(self, auth_client):
+        resp = auth_client.get("/dashboard")
+        html = resp.data.decode()
+        assert 'name="current_password"' in html
+        assert 'name="new_password"' in html
+        assert 'name="confirm_password"' in html
+
+    def test_change_password_wrong_current(self, auth_client):
+        resp = auth_client.post("/change-password", data={
+            "current_password": "wrongpass",
+            "new_password": "newpass123",
+            "confirm_password": "newpass123",
+        }, follow_redirects=True)
+        assert b"incorrect" in resp.data.lower()
+
+    def test_change_password_success(self, auth_client):
+        """Bob changes password, then logs in with it."""
+        resp = auth_client.post("/change-password", data={
+            "current_password": "bobpass",
+            "new_password": "newbobpass",
+            "confirm_password": "newbobpass",
+        }, follow_redirects=True)
+        assert b"success" in resp.data.lower() or b"changed" in resp.data.lower()
+
+        # Verify new password works
+        auth_client.get("/logout")
+        login_resp = auth_client.post("/login", data={
+            "username": "bob", "password": "newbobpass",
+        }, follow_redirects=True)
+        assert login_resp.status_code == 200
+
+    def test_change_password_mismatch(self, auth_client):
+        resp = auth_client.post("/change-password", data={
+            "current_password": "bobpass",
+            "new_password": "aaa1234",
+            "confirm_password": "bbb5678",
+        }, follow_redirects=True)
+        assert b"do not match" in resp.data.lower()
+
+    def test_change_password_too_short(self, auth_client):
+        resp = auth_client.post("/change-password", data={
+            "current_password": "bobpass",
+            "new_password": "ab",
+            "confirm_password": "ab",
+        }, follow_redirects=True)
+        assert b"at least 4" in resp.data.lower()
+
+    def test_delete_account_form_requires_password(self, auth_client):
+        resp = auth_client.get("/dashboard")
+        html = resp.data.decode()
+        assert "Delete My Account" in html or "Supprimer mon compte" in html or "Mein Konto" in html
+        assert 'action="/delete-account"' in html or 'action="/dashboard' in html
+
+
+# ═══════════════════════════════════════════════════════════════════════════════
+#  Household settings page (admin only)
+# ═══════════════════════════════════════════════════════════════════════════════
+
+class TestHouseholdSettingsUI:
+
+    def test_household_section_hidden_from_regular_user(self, auth_client):
+        """Bob is not admin — household settings should not appear."""
+        resp = auth_client.get("/dashboard")
+        html = resp.data.decode()
+        assert "Household Settings" not in html
+        assert "Paramètres du foyer" not in html
+        assert "Haushaltseinstellungen" not in html
+
+    def test_admin_sees_household_section(self, admin_client):
+        resp = admin_client.get("/dashboard")
+        html = resp.data.decode()
+        assert "Household Settings" in html or "Paramètres du foyer" in html or "Haushaltseinstellungen" in html
+
+    def test_admin_sees_public_link_section(self, admin_client):
+        resp = admin_client.get("/dashboard")
+        html = resp.data.decode()
+        assert "Public Sharing Link" in html or "Lien de partage" in html or "Freigabelink" in html
+
+    def test_admin_sees_timezone_section(self, admin_client):
+        resp = admin_client.get("/dashboard")
+        html = resp.data.decode()
+        assert 'name="timezone"' in html
+
+    def test_admin_sees_delete_household_section(self, admin_client):
+        resp = admin_client.get("/dashboard")
+        html = resp.data.decode()
+        assert "Delete Household" in html or "Supprimer le foyer" in html or "Haushalt löschen" in html
+
+    def test_generate_public_link_displays_url(self, admin_client):
+        resp = admin_client.post("/admin/public-link", data={
+            "action": "generate",
+        }, follow_redirects=True)
+        assert resp.status_code == 200
+        assert b"public/" in resp.data
+
+    def test_disable_public_link_hides_url(self, admin_client):
+        # First generate
+        admin_client.post("/admin/public-link", data={"action": "generate"})
+        # Then disable
+        resp = admin_client.post("/admin/public-link", data={
+            "action": "disable",
+        }, follow_redirects=True)
+        assert b"disabled" in resp.data.lower()
+
+    def test_enable_public_link_after_disable(self, admin_client):
+        admin_client.post("/admin/public-link", data={"action": "generate"})
+        admin_client.post("/admin/public-link", data={"action": "disable"})
+        resp = admin_client.post("/admin/public-link", data={
+            "action": "enable",
+        }, follow_redirects=True)
+        assert ("enabled" in resp.data.decode().lower()
+                or "activé" in resp.data.decode().lower())
+
+
+# ═══════════════════════════════════════════════════════════════════════════════
+#  Public sharing page
+# ═══════════════════════════════════════════════════════════════════════════════
+
+class TestPublicPageUI:
+
+    @pytest.fixture
+    def public_token(self, admin_client):
+        """Create a household with a public token and return it."""
+        from models import get_db
+        db = get_db()
+        row = db.execute(
+            "SELECT h.id, h.public_token FROM households h "
+            "JOIN users u ON u.household_id = h.id WHERE u.username = ?",
+            ("admin",),
+        ).fetchone()
+        # Generate if missing
+        if not row["public_token"]:
+            token = generate_public_token(row["id"])
+        else:
+            token = row["public_token"]
+        return token
+
+    def test_public_page_shows_household_name(self, client, admin_client, public_token):
+        resp = client.get(f"/public/{public_token}")
+        assert resp.status_code == 200
+        assert b"Admin Household" in resp.data
+
+    def test_public_page_has_no_response_buttons(self, client, public_token):
+        """Public page is read-only — no forms to respond to meals."""
+        resp = client.get(f"/public/{public_token}")
+        html = resp.data.decode()
+        assert 'name="status"' not in html
+        assert 'name="meal_type"' not in html
+
+    def test_public_page_has_date_nav(self, client, public_token):
+        resp = client.get(f"/public/{public_token}")
+        html = resp.data.decode()
+        assert "Prev" in html or "Préc" in html or "Zurück" in html
+        assert "Next" in html or "Suiv" in html or "Weiter" in html
+
+    def test_invalid_token_returns_404(self, client):
+        resp = client.get("/public/this-token-does-not-exist")
+        assert resp.status_code == 404
+
+    def test_disabled_token_returns_404(self, client, admin_client):
+        admin_client.post("/admin/public-link", data={"action": "generate"})
+        from models import get_db
+        db = get_db()
+        row = db.execute(
+            "SELECT h.public_token FROM households h "
+            "JOIN users u ON u.household_id = h.id WHERE u.username = ?",
+            ("admin",),
+        ).fetchone()
+        token = row["public_token"]
+        # Disable it
+        admin_client.post("/admin/public-link", data={"action": "disable"})
+        resp = client.get(f"/public/{token}")
+        assert resp.status_code == 404
+
+
+# ═══════════════════════════════════════════════════════════════════════════════
+#  Language / i18n
+# ═══════════════════════════════════════════════════════════════════════════════
+
+class TestLanguageUI:
+
+    def test_default_is_english(self, client):
+        resp = client.get("/login")
+        assert b"Log In" in resp.data or b"Username" in resp.data
+
+    def test_french_language_switch(self, client):
+        resp = client.get("/login?lang=fr")
+        assert b"Se connecter" in resp.data or b"Nom d" in resp.data
+
+    def test_german_language_switch(self, client):
+        resp = client.get("/login?lang=de")
+        assert b"Anmelden" in resp.data or b"Benutzername" in resp.data
+
+    def test_language_persists_in_session(self, client):
+        # Set language, then request another page
+        client.get("/login?lang=fr")
+        resp = client.get("/register")
+        # Should still show French
+        html = resp.data.decode()
+        assert ("Créer" in html or "S'inscrire" in html
+                or "compte" in html.lower())
+
+    def test_public_page_supports_language(self, client, admin_client):
+        admin_client.post("/admin/public-link", data={"action": "generate"})
+        from models import get_db
+        db = get_db()
+        row = db.execute(
+            "SELECT h.public_token FROM households h "
+            "JOIN users u ON u.household_id = h.id WHERE u.username = ?",
+            ("admin",),
+        ).fetchone()
+        token = row["public_token"]
+
+        resp = client.get(f"/public/{token}?lang=fr")
+        assert resp.status_code == 200
+        # Should show French content
+        html = resp.data.decode()
+        assert ("Déjeuner" in html or "Dîner" in html
+                or "Présent" in html)
+
+    def test_language_footer_links_present(self, client):
+        resp = client.get("/login")
+        html = resp.data.decode()
+        assert "EN" in html and "FR" in html and "DE" in html