diff --git a/app/globals.css b/app/globals.css
index c1d473154..94c1acac4 100644
--- a/app/globals.css
+++ b/app/globals.css
@@ -1351,15 +1351,6 @@ optgroup {
   inset-inline-end: 0;
 }
 
-/* A phone on its side counts as a tablet, which keeps the bottom bar. With a
-   message or the composer open the bar takes a sixth of a window this short and
-   leaves the message a few lines; a phone held upright hides it there too. */
-@media (max-height: 32rem) {
-  body:has([data-tour="email-viewer"], [data-tour="composer"]) [data-mobile-navigation] {
-    display: none;
-  }
-}
-
 /* The account popover: a wide card with a very round corner, rather
    than the narrow menu the rail and the sidebar switchers drop. */
 [data-interface-layout="mountain-view"] [data-mv-account-popover] {
diff --git a/components/mail/__tests__/mail-app-short-window-tab-bar.test.tsx b/components/mail/__tests__/mail-app-short-window-tab-bar.test.tsx
new file mode 100644
index 000000000..8e4932e68
--- /dev/null
+++ b/components/mail/__tests__/mail-app-short-window-tab-bar.test.tsx
@@ -0,0 +1,129 @@
+import React from 'react';
+import { fireEvent, render, screen } from '@testing-library/react';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import type { Email, Mailbox } from '@/lib/jmap/types';
+import { useAuthStore } from '@/stores/auth-store';
+import { useEmailStore } from '@/stores/email-store';
+import { useSettingsStore } from '@/stores/settings-store';
+import { usePluginStore } from '@/stores/plugin-store';
+import { useThemeStore } from '@/stores/theme-store';
+import { useUIStore } from '@/stores/ui-store';
+import { DEFAULT_SEARCH_FILTERS } from '@/lib/jmap/search-utils';
+
+// A phone on its side: the bottom bar takes a sixth of the window, so it goes
+// over what fills the window. It stays wherever the list shows, or there is no
+// way left to the other apps.
+
+const device = vi.hoisted(() => ({ current: { isMobile: false, isTablet: true, isDesktop: false }, short: true }));
+
+vi.mock('@/hooks/use-media-query', () => ({
+  useDeviceDetection: () => device.current,
+  useMediaQuery: (query: string) => query.includes('max-height') && device.short,
+  useIsDesktop: () => false,
+}));
+vi.mock('@/components/layout/navigation-rail', () => ({ NavigationRail: () => <nav>tab bar</nav> }));
+vi.mock('@/components/layout/sidebar', () => ({
+  Sidebar: ({ onCompose }: { onCompose: () => void }) => <button onClick={onCompose}>stub compose</button>,
+}));
+vi.mock('@/components/email/email-composer', () => ({ EmailComposer: () => <p>stub composer</p> }));
+vi.mock('@/components/email/email-viewer', () => ({ EmailViewer: () => <div>message viewer</div> }));
+vi.mock('@/components/layout/mv-top-bar', () => ({ MvTopBar: () => null }));
+vi.mock('@/components/search/mv-search-form', () => ({ MvSearchForm: () => null }));
+vi.mock('@/components/layout/calendar-event-notification-toaster', () => ({ CalendarEventNotificationToaster: () => null }));
+vi.mock('@/components/layout/share-notification-toaster', () => ({ ShareNotificationToaster: () => null }));
+vi.mock('@/components/layout/mobile-header', () => ({ MobileHeader: () => null }));
+vi.mock('@/components/layout/mv-side-panel', () => ({ MvSidePanel: () => null }));
+vi.mock('@/components/email/message-list-tabs', () => ({ useMessageListPanelProps: (id: string) => ({ id }), MessageListTabs: () => null }));
+vi.mock('@/components/search/search-box', () => ({ SearchBox: () => null }));
+vi.mock('@/components/tour/tour-provider', () => ({ useTour: () => ({ activeTour: null, registerStep: vi.fn() }) }));
+vi.mock('@/components/plugins/plugin-slot', () => ({ PluginSlot: () => null }));
+vi.mock('@/hooks/use-plugin-slot-offers', () => ({ usePluginSlotOffers: () => [] }));
+vi.mock('@/hooks/use-config', () => ({ useConfig: () => ({ appName: 'Mail' }) }));
+vi.mock('@/hooks/use-identity-sync', () => ({ useIdentitySync: () => {} }));
+vi.mock('@/hooks/use-pro-multi-account-identities', () => ({ useProMultiAccountIdentities: () => [] }));
+vi.mock('@/hooks/use-pro-multi-account-mailboxes', () => ({ useProMultiAccountMailboxes: () => {} }));
+vi.mock('@/hooks/use-wopi-status', () => ({ useWopiStatus: () => null, canWopiOpen: () => false }));
+vi.mock('@/hooks/use-browser-navigation', () => ({ useBrowserNavigation: () => {} }));
+vi.mock('@/lib/push-bindings', () => ({ reconcilePushBindings: () => {}, releasePushBindings: () => {} }));
+vi.mock('@/components/email/email-list', () => ({ EmailList: () => <div>message list</div> }));
+
+const { MailApp } = await import('../mail-app');
+
+const inbox = { id: 'inbox', name: 'Inbox', role: 'inbox', totalEmails: 1, unreadEmails: 0 } as Mailbox;
+const message = { id: 'm1', threadId: 't-m1', subject: 'm1', receivedAt: '2026-10-31T10:00:00Z', keywords: { $seen: true }, mailboxIds: { inbox: true } } as unknown as Email;
+
+beforeEach(() => {
+  device.current = { isMobile: false, isTablet: true, isDesktop: false };
+  device.short = true;
+  vi.stubGlobal('fetch', vi.fn().mockRejectedValue(new Error('Unexpected network request')));
+  vi.stubGlobal('ResizeObserver', class { observe() {} unobserve() {} disconnect() {} });
+  usePluginStore.setState({ initializePlugins: vi.fn().mockResolvedValue(undefined) });
+  useThemeStore.setState({ syncServerThemes: vi.fn().mockResolvedValue(undefined) });
+  const client = {
+    getAccountId: () => 'acc', getUsername: () => 'a@example.org',
+    getSieveAccountId: () => null, hasDelayedSend: () => false, getSession: () => null,
+  };
+  useAuthStore.setState({
+    isAuthenticated: true, isLoading: false, client: client as never, activeAccountId: 'login-a', identities: [],
+    getClientForAccount: () => client as never,
+    getAllConnectedClients: () => new Map([['login-a', client]]) as never,
+  });
+  useSettingsStore.setState({ enableUnifiedMailbox: false, interfaceLayout: 'default', mailLayout: 'split' } as never);
+  useUIStore.setState({ activeView: 'list', tabletListVisible: true, sidebarOpen: false });
+  useEmailStore.setState({
+    emails: [message], selectedEmail: null, selectedMailbox: 'inbox', selectedKeyword: null, mailboxes: [inbox],
+    viewingAccountId: null, accountMailboxes: {}, isUnifiedView: false, unifiedRole: null,
+    isScheduledView: false, isLoadingEmail: false, isLoading: false, searchQuery: '',
+    searchFilters: { ...DEFAULT_SEARCH_FILTERS }, searchMailboxId: '', isAdvancedSearchOpen: false,
+    selectedEmailKeys: new Set(), unreadSection: null,
+    fetchMailboxes: vi.fn().mockResolvedValue(undefined), fetchEmails: vi.fn().mockResolvedValue(undefined),
+    fetchQuota: vi.fn().mockResolvedValue(undefined), fetchTagCounts: vi.fn().mockResolvedValue(undefined),
+    refreshScheduledMetadata: vi.fn().mockResolvedValue(undefined),
+    fetchEmailContent: vi.fn().mockResolvedValue(undefined),
+    markAsRead: vi.fn().mockResolvedValue(undefined),
+  } as never);
+});
+afterEach(() => {
+  vi.restoreAllMocks();
+  vi.unstubAllGlobals();
+});
+
+const tabBar = () => screen.queryByText('tab bar');
+
+describe('the bottom bar in a short window', () => {
+  it('stays with the list beside an open message', () => {
+    useEmailStore.setState({ selectedEmail: message } as never);
+    render(<MailApp />);
+    expect(tabBar()).not.toBeNull();
+  });
+
+  it('goes when the message fills the window', () => {
+    useUIStore.setState({ tabletListVisible: false });
+    useEmailStore.setState({ selectedEmail: message } as never);
+    render(<MailApp />);
+    expect(tabBar()).toBeNull();
+  });
+
+  it('goes over a composer, and comes back without one', async () => {
+    render(<MailApp />);
+    expect(tabBar()).not.toBeNull();
+    fireEvent.click(screen.getByText('stub compose'));
+    await screen.findByText('stub composer', {}, { timeout: 5000 });
+    expect(tabBar()).toBeNull();
+  });
+
+  it('stays in a tall window whatever is open', () => {
+    device.short = false;
+    useUIStore.setState({ tabletListVisible: false });
+    useEmailStore.setState({ selectedEmail: message } as never);
+    render(<MailApp />);
+    expect(tabBar()).not.toBeNull();
+  });
+
+  it('stays on a phone\'s list with a message kept selected behind it', () => {
+    device.current = { isMobile: true, isTablet: false, isDesktop: false };
+    useEmailStore.setState({ selectedEmail: message } as never);
+    render(<MailApp />);
+    expect(tabBar()).not.toBeNull();
+  });
+});
diff --git a/components/mail/mail-app.tsx b/components/mail/mail-app.tsx
index f80b0c5ca..065b501ae 100644
--- a/components/mail/mail-app.tsx
+++ b/components/mail/mail-app.tsx
@@ -58,7 +58,7 @@ import { useEffectiveMailLayout } from "@/hooks/use-effective-mail-layout";
 import { useContactStore } from "@/stores/contact-store";
 import { useIdentityStore } from "@/stores/identity-store";
 import { useUIStore, listPaneCssSize, SIDEBAR_MIN, SIDEBAR_MAX, EMAIL_LIST_MIN, EMAIL_LIST_MAX, EMAIL_LIST_HEIGHT_MIN, EMAIL_LIST_HEIGHT_MAX, READING_PANE_MIN_WIDTH, READING_PANE_MIN_HEIGHT, COMPOSER_PANE_MIN_HEIGHT } from "@/stores/ui-store";
-import { atLeast, useDeviceDetection } from "@/hooks/use-media-query";
+import { atLeast, useDeviceDetection, useMediaQuery } from "@/hooks/use-media-query";
 import { usePaneSize } from "@/hooks/use-pane-size";
 import { useIsFocusedProTab, usePaneId } from "@/hooks/use-pane-context";
 import { useKeyboardShortcuts, type GoToMailboxTarget } from "@/hooks/use-keyboard-shortcuts";
@@ -386,6 +386,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
 
   // Mobile/tablet responsive hooks
   const { isMobile, isTablet } = useDeviceDetection();
+  const isShortWindow = useMediaQuery('(max-height: 32rem)');
   const isEmbedded = useIsEmbedded();
   // A message or conversation link shows the reader from the first frame, as
   // the page skeleton draws it, in its loading state until the link has been
@@ -4616,6 +4617,11 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
   const mobileView = deepLinkPane !== null && isMobile ? 'viewer' : activeView;
   const shouldCollapseListPane = (isTablet && ((!tabletListVisible && !readingPaneEmpty) || deepLinkPane !== null)) || (!isMobile && isFocusedMailLayout && hasViewerContent);
   const shouldHideViewerPane = !isMobile && !hasViewerContent && isFocusedMailLayout;
+  // A phone on its side counts as a tablet, which keeps the bottom bar. In a window
+  // this short the bar takes a sixth of it and leaves a few lines, so it goes where
+  // a phone held upright hides it too: over a composer, or a message filling the
+  // window. With the list beside the message it is the only way to the other apps.
+  const shortWindowHidesTabBar = isShortWindow && ((showComposer && !floatingComposer) || (hasViewerContent && shouldCollapseListPane));
   const shouldHideHorizontalViewerPane = isHorizontalMailLayout && !hasViewerContent;
 
   // Handle email selection with mobile view switching
@@ -5903,7 +5909,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
           </div>
 
           {/* Bottom Navigation - mobile and tablet (hidden when embedded) */}
-          {(isMobile || isTablet) && mobileView !== "viewer" && !isEmbedded && (
+          {(isMobile || isTablet) && mobileView !== "viewer" && !shortWindowHidesTabBar && !isEmbedded && (
             <NavigationRail
               orientation="horizontal"
               onManageApps={handleManageApps}