diff --git a/.env.example b/.env.example
index 99da0cb0..5f21140e 100644
--- a/.env.example
+++ b/.env.example
@@ -234,6 +234,22 @@ LOGIN_WEBSITE_URL=https://bulwarkmail.org
 # your own directory (e.g. http://localhost:3001 for local development).
 # EXTENSION_DIRECTORY_URL=https://extensions.bulwarkmail.org
 
+# =============================================================================
+# Internationalization
+# =============================================================================
+# These are build-time variables - to change them with the published Docker
+# image, rebuild it with --build-arg (see README "Default UI locale").
+#
+# Fallback UI locale used when the visitor's Accept-Language header does not
+# match any supported locale. Defaults to "en".
+# Supported: cs, da, de, en, es, fr, it, ja, ko, lv, nl, pl, pt, ru, tr, uk, zh
+# NEXT_PUBLIC_DEFAULT_LOCALE=tr
+
+# Locale prefix mode for URLs. Recommended "always" when proxying under a
+# subpath (NEXT_PUBLIC_BASE_PATH) to avoid next-intl rewrite loops.
+# Values: never (default) | always | as-needed
+# NEXT_PUBLIC_LOCALE_PREFIX=always
+
 # =============================================================================
 # Legacy Build-time Variables (still supported as fallback)
 # =============================================================================
diff --git a/Dockerfile b/Dockerfile
index 8e3a3e68..2b7c21ae 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -8,6 +8,11 @@ ENV NEXT_TELEMETRY_DISABLED=1
 # at build time, so it cannot be changed without rebuilding.
 ARG NEXT_PUBLIC_BASE_PATH=
 ENV NEXT_PUBLIC_BASE_PATH=$NEXT_PUBLIC_BASE_PATH
+# Optional: fallback UI locale (e.g. tr, de, fr) used when the visitor's
+# Accept-Language header does not match any supported locale. Baked in at
+# build time because next-intl wires it into client-side routing too.
+ARG NEXT_PUBLIC_DEFAULT_LOCALE=
+ENV NEXT_PUBLIC_DEFAULT_LOCALE=$NEXT_PUBLIC_DEFAULT_LOCALE
 # Commit SHA shown in the About screen. .dockerignore excludes .git, so
 # `git rev-parse` inside the build can't find it - CI must pass it in.
 ARG GIT_COMMIT=unknown
diff --git a/app/(main)/[locale]/login/page.tsx b/app/(main)/[locale]/login/page.tsx
index 0ef6ccd7..953195f4 100644
--- a/app/(main)/[locale]/login/page.tsx
+++ b/app/(main)/[locale]/login/page.tsx
@@ -11,7 +11,7 @@ import { useAccountStore } from "@/stores/account-store";
 import { useThemeStore } from "@/stores/theme-store";
 import { useShallow } from "zustand/react/shallow";
 import { useConfig } from "@/hooks/use-config";
-import { apiFetch, getPathPrefix } from "@/lib/browser-navigation";
+import { apiFetch, getPathPrefix, withBasePath } from "@/lib/browser-navigation";
 import { cn } from "@/lib/utils";
 import { AlertCircle, Loader2, X, Info, Eye, EyeOff, LogIn, Sun, Moon, Monitor, Check, Shield, Play, Copy } from "lucide-react";
 import { discoverOAuth, type OAuthMetadata } from "@/lib/oauth/discovery";
@@ -722,7 +722,7 @@ export default function LoginPage() {
             <div className="px-8 pt-12 pb-4 text-center">
               <div className="inline-flex items-center justify-center w-20 h-20 mb-6">
                 <img
-                  src={resolvedTheme === 'dark' ? loginLogoDarkUrl : loginLogoLightUrl}
+                  src={withBasePath(resolvedTheme === 'dark' ? loginLogoDarkUrl : loginLogoLightUrl)}
                   alt={appName}
                   className="max-w-20 max-h-20 object-contain"
                 />
@@ -872,7 +872,7 @@ export default function LoginPage() {
           <div className="px-8 pt-10 pb-6 text-center">
             <div className="inline-flex items-center justify-center w-16 h-16 mb-5">
               <img
-                src={resolvedTheme === 'dark' ? loginLogoDarkUrl : loginLogoLightUrl}
+                src={withBasePath(resolvedTheme === 'dark' ? loginLogoDarkUrl : loginLogoLightUrl)}
                 alt={appName}
                 className="max-w-16 max-h-16 object-contain"
               />
diff --git a/app/(main)/[locale]/page.tsx b/app/(main)/[locale]/page.tsx
index e9c283ef..24db868d 100644
--- a/app/(main)/[locale]/page.tsx
+++ b/app/(main)/[locale]/page.tsx
@@ -15,7 +15,7 @@ import { ThreadGroup, Email, isUnifiedMailboxId, UNIFIED_ROLE_BY_ID } from "@/li
 import { useAccountStore } from "@/stores/account-store";
 import type { UnifiedAccountClient } from "@/lib/unified-mailbox";
 import { KeyboardShortcutsModal } from "@/components/keyboard-shortcuts-modal";
-import { useEmailStore } from "@/stores/email-store";
+import { useEmailStore, buildUnifiedAccountClients } from "@/stores/email-store";
 import { toast } from "@/stores/toast-store";
 import { useAuthStore, redirectToLogin } from "@/stores/auth-store";
 import { useSettingsStore } from "@/stores/settings-store";
@@ -342,47 +342,22 @@ export default function Home() {
   const activeEmails = isScheduledView ? scheduledEmails : emails;
   const activeHasMore = isScheduledView ? scheduledHasMore : hasMoreEmails;
   const activeIsLoading = isScheduledView ? isLoadingScheduled : isLoading;
+  const includeGroupInUnified = useSettingsStore((s) => s.includeGroupInUnified);
   const accounts = useAccountStore((s) => s.accounts);
   const connectedAccountsSignature = useMemo(
     () => accounts.filter((a) => a.isConnected).map((a) => a.id).sort().join(","),
     [accounts],
   );
 
-  const buildUnifiedAccounts = useCallback((): UnifiedAccountClient[] => {
-    const connected = useAccountStore.getState().accounts.filter((a) => a.isConnected);
-    const clients = useAuthStore.getState().getAllConnectedClients();
-    const result: UnifiedAccountClient[] = [];
-    for (const account of connected) {
-      const accountClient = clients.get(account.id);
-      if (!accountClient) continue;
-      result.push({
-        accountId: account.id,
-        accountLabel: account.label || account.email,
-        client: accountClient,
-        mailboxes: [],
-      });
-    }
-    return result;
+  // Builds the populated UnifiedAccountClient[] used by the unified-view
+  // effects and one-shot actions in this page. Reads the includeGroup
+  // setting at call time so the latest toggle value is always honored.
+  const buildPopulatedUnifiedAccounts = useCallback(async (): Promise<UnifiedAccountClient[]> => {
+    return buildUnifiedAccountClients({
+      includeGroup: useSettingsStore.getState().includeGroupInUnified,
+    });
   }, []);
 
-  const populateUnifiedAccountMailboxes = useCallback(
-    async (list: UnifiedAccountClient[]): Promise<UnifiedAccountClient[]> => {
-      const populated = await Promise.all(
-        list.map(async (entry) => {
-          try {
-            const mailboxes = await entry.client.getMailboxes();
-            return { ...entry, mailboxes };
-          } catch (err) {
-            debug.error('Failed to load mailboxes for unified account', entry.accountId, err);
-            return entry;
-          }
-        }),
-      );
-      return populated;
-    },
-    [],
-  );
-
   const getMailtoProtocolAccounts = useCallback(() => {
     const connectedClients = useAuthStore.getState().getAllConnectedClients();
     return useAccountStore.getState().accounts.filter((account) =>
@@ -1004,12 +979,12 @@ export default function Home() {
   useEffect(() => {
     if (!enableUnifiedMailbox && !isEmbedded) return;
     if (!isAuthenticated || !client) return;
-    const built = buildUnifiedAccounts();
-    if (built.length < 2) return;
-    populateUnifiedAccountMailboxes(built).then((populated) => {
-      refreshUnifiedCounts(populated);
+    buildPopulatedUnifiedAccounts().then((built) => {
+      const hasGroupEntry = built.some((b) => b.isShared);
+      if (built.length < 2 && !hasGroupEntry && !isEmbedded) return;
+      refreshUnifiedCounts(built);
     });
-  }, [enableUnifiedMailbox, isEmbedded, isAuthenticated, client, mailboxes, connectedAccountsSignature, buildUnifiedAccounts, populateUnifiedAccountMailboxes, refreshUnifiedCounts]);
+  }, [enableUnifiedMailbox, includeGroupInUnified, isEmbedded, isAuthenticated, client, mailboxes, connectedAccountsSignature, buildPopulatedUnifiedAccounts, refreshUnifiedCounts]);
 
   // System-notification click handler. The push SW navigates the user back
   // here with `?email=<id>` (specific email it built the toast from) or
@@ -1656,8 +1631,7 @@ export default function Home() {
         setTabletListVisible(true);
       }
 
-      const built = buildUnifiedAccounts();
-      const populated = await populateUnifiedAccountMailboxes(built);
+      const populated = await buildPopulatedUnifiedAccounts();
       await fetchUnifiedEmailsAction(populated, role);
       refreshUnifiedCounts(populated);
       return;
@@ -2004,8 +1978,7 @@ export default function Home() {
     if (isUnifiedView) {
       const role = useEmailStore.getState().unifiedRole;
       if (role) {
-        const built = buildUnifiedAccounts();
-        const populated = await populateUnifiedAccountMailboxes(built);
+        const populated = await buildPopulatedUnifiedAccounts();
         await fetchUnifiedEmailsAction(populated, role);
       }
       return;
@@ -2180,7 +2153,7 @@ export default function Home() {
   const isHorizontalMailLayout = mailLayout === 'horizontal' && !isMobile && !isTablet;
   const hasViewerContent = showComposer || Boolean(conversationThread) || Boolean(selectedEmail);
   const shouldCollapseListPane = (isTablet && !tabletListVisible) || (!isMobile && isFocusedMailLayout && hasViewerContent);
-  const shouldHideViewerPane = !isMobile && !hasViewerContent && (isEmbedded || isFocusedMailLayout);
+  const shouldHideViewerPane = !isMobile && !hasViewerContent && isFocusedMailLayout;
   const shouldHideHorizontalViewerPane = isHorizontalMailLayout && !hasViewerContent;
 
   // Handle email selection with mobile view switching
diff --git a/app/(main)/admin/_tabs/_jmap-servers-section.tsx b/app/(main)/admin/_tabs/_jmap-servers-section.tsx
index 69f6091d..638e9fee 100644
--- a/app/(main)/admin/_tabs/_jmap-servers-section.tsx
+++ b/app/(main)/admin/_tabs/_jmap-servers-section.tsx
@@ -1,6 +1,6 @@
 'use client';
 
-import { useEffect, useState } from 'react';
+import { useEffect, useRef, useState } from 'react';
 import { Plus, Trash2, RotateCcw, ChevronDown, ChevronRight } from 'lucide-react';
 import type { JmapServerEntry } from '@/lib/admin/jmap-servers';
 
@@ -77,30 +77,17 @@ function emptyDraft(): RowDraft {
 
 export function JmapServersSection({ value, source, onChange, onRevert }: Props) {
   const [drafts, setDrafts] = useState<RowDraft[]>(() => value.map(entryToDraft));
+  const lastEmittedRef = useRef(value);
 
   useEffect(() => {
-    // Re-sync from props when the underlying config value changes (e.g. revert,
-    // initial load). Skip when drafts already represent the same array to avoid
-    // clobbering in-progress edits.
-    setDrafts((prev) => {
-      if (prev.length === value.length) {
-        const same = prev.every((d, i) => {
-          const e = value[i];
-          return d.id === e.id && d.url === e.url && d.label === e.label;
-        });
-        if (same) return prev;
-      }
-      return value.map(entryToDraft);
-    });
+    if (value === lastEmittedRef.current) return;
+    setDrafts(value.map(entryToDraft))
   }, [value]);
 
   function commit(next: RowDraft[]) {
     setDrafts(next);
-    const entries: JmapServerEntry[] = [];
-    for (const d of next) {
-      const e = draftToEntry(d);
-      if (e) entries.push(e);
-    }
+    const entries = next.map(draftToEntry).filter((e): e is JmapServerEntry => e !== null);
+    lastEmittedRef.current = entries;
     onChange(entries);
   }
 
diff --git a/app/(main)/admin/layout.tsx b/app/(main)/admin/layout.tsx
index a792703a..19fd9020 100644
--- a/app/(main)/admin/layout.tsx
+++ b/app/(main)/admin/layout.tsx
@@ -32,7 +32,7 @@ import { useThemeStore } from '@/stores/theme-store';
 import { getActiveAccountSlotHeaders } from '@/lib/auth/active-account-slot';
 
 import { useUpdateStore, selectHasUpdate } from '@/stores/update-store';
-import { apiFetch, getPathPrefix } from '@/lib/browser-navigation';
+import { apiFetch, getPathPrefix, withBasePath } from '@/lib/browser-navigation';
 
 // Single-page tab navigation: clicks update a Zustand store. The URL stays
 // at /admin so React doesn't fire a route transition on every tab switch -
@@ -90,9 +90,9 @@ export default function AdminLayout({ children }: { children: React.ReactNode })
   const { appLogoLightUrl, appLogoDarkUrl, loginLogoLightUrl, loginLogoDarkUrl } = useConfig();
   const filesEnabled = usePolicyStore((s) => s.isFeatureEnabled('filesEnabled'));
   const resolvedTheme = useThemeStore((s) => s.resolvedTheme);
-  const logoUrl = resolvedTheme === 'dark'
+  const logoUrl = withBasePath(resolvedTheme === 'dark'
     ? (appLogoDarkUrl || appLogoLightUrl || loginLogoDarkUrl)
-    : (appLogoLightUrl || appLogoDarkUrl || loginLogoLightUrl);
+    : (appLogoLightUrl || appLogoDarkUrl || loginLogoLightUrl));
 
   // Match the navigation rail: red for security/deprecated, amber for normal.
   const hasUpdate = useUpdateStore(selectHasUpdate);
diff --git a/app/(main)/admin/login/page.tsx b/app/(main)/admin/login/page.tsx
index 9f57f3b3..018777d4 100644
--- a/app/(main)/admin/login/page.tsx
+++ b/app/(main)/admin/login/page.tsx
@@ -5,7 +5,7 @@ import { useRouter } from 'next/navigation';
 import { Shield } from 'lucide-react';
 import { useConfig } from '@/hooks/use-config';
 import { useThemeStore } from '@/stores/theme-store';
-import { apiFetch } from '@/lib/browser-navigation';
+import { apiFetch, withBasePath } from '@/lib/browser-navigation';
 
 export default function AdminLoginPage() {
   const router = useRouter();
@@ -14,7 +14,7 @@ export default function AdminLoginPage() {
   const [loading, setLoading] = useState(false);
   const { loginLogoLightUrl, loginLogoDarkUrl } = useConfig();
   const resolvedTheme = useThemeStore((s) => s.resolvedTheme);
-  const logoUrl = resolvedTheme === 'dark' ? loginLogoDarkUrl : loginLogoLightUrl;
+  const logoUrl = withBasePath(resolvedTheme === 'dark' ? loginLogoDarkUrl : loginLogoLightUrl);
 
   async function handleSubmit(e: FormEvent) {
     e.preventDefault();
diff --git a/app/(main)/layout.tsx b/app/(main)/layout.tsx
index b98b064c..ac5c3b42 100644
--- a/app/(main)/layout.tsx
+++ b/app/(main)/layout.tsx
@@ -5,6 +5,7 @@ import { getLocale } from "next-intl/server";
 import { PWAInstallPrompt } from "@/components/pwa-install-prompt";
 import { ServiceWorkerRegistration } from "@/components/service-worker-registration";
 import { configManager } from "@/lib/admin/config-manager";
+import { withBasePath } from "@/lib/browser-navigation";
 import "../globals.css";
 
 const geistSans = Geist({
@@ -38,7 +39,7 @@ export async function generateMetadata(): Promise<Metadata> {
     formatDetection: {
       telephone: false,
     },
-    icons: { icon: faviconUrl },
+    icons: { icon: withBasePath(faviconUrl) },
   };
 }
 
diff --git a/app/(main)/setup/page.tsx b/app/(main)/setup/page.tsx
index 686bb202..c40664f5 100644
--- a/app/(main)/setup/page.tsx
+++ b/app/(main)/setup/page.tsx
@@ -3,7 +3,7 @@
 import { useEffect, useState, type FormEvent, type ReactNode } from 'react';
 import { useRouter, useSearchParams } from 'next/navigation';
 import { CheckCircle2, AlertTriangle, AlertCircle, Server, ShieldCheck, KeyRound, FileText, Palette, Lock, ShieldAlert } from 'lucide-react';
-import { apiFetch, getPathPrefix } from '@/lib/browser-navigation';
+import { apiFetch, getPathPrefix, withBasePath } from '@/lib/browser-navigation';
 
 type State = 'bootstrap' | 'configured' | 'env-managed';
 
@@ -1329,7 +1329,7 @@ function BrandingAsset({
             }}
           />
           {value ? (
-            <img src={value} alt="" className="max-w-full max-h-full object-contain" />
+            <img src={withBasePath(value)} alt="" className="max-w-full max-h-full object-contain" />
           ) : (
             <span className="text-[10px] text-muted-foreground text-center px-1">click or drop</span>
           )}
diff --git a/components/calendar/event-card.tsx b/components/calendar/event-card.tsx
index f797f0ea..4886324c 100644
--- a/components/calendar/event-card.tsx
+++ b/components/calendar/event-card.tsx
@@ -157,7 +157,6 @@ export function EventCard({ event, calendar, variant, onClick, onMouseEnter, onM
           "w-full h-full text-left rounded-r px-1.5 py-0.5 text-xs overflow-hidden",
           "hover:opacity-90 transition-opacity cursor-pointer",
           continuesAfter && "rounded-r-sm",
-          continuesBefore && "-ml-0.5",
           continuesAfter && "pr-2",
           isSelected && "ring-2 ring-primary",
           isBeingDragged && "opacity-50",
diff --git a/components/calendar/event-detail-popover.tsx b/components/calendar/event-detail-popover.tsx
index 78de3c28..1f0e4f67 100644
--- a/components/calendar/event-detail-popover.tsx
+++ b/components/calendar/event-detail-popover.tsx
@@ -8,11 +8,11 @@ import {
   X, Clock, MapPin, Video, Users, Repeat, Bell, AlignLeft,
   Pencil, Trash2, Copy, Send, Check,
 } from "lucide-react";
-import { format, parseISO } from "date-fns";
+import { format, isSameDay, parseISO } from "date-fns";
 import { cn } from "@/lib/utils";
 import type { CalendarEvent, Calendar, CalendarParticipant } from "@/lib/jmap/types";
 import { parseDuration, getEventColor } from "./event-card";
-import { getEventEndDate, getEventStartDate } from "@/lib/calendar-utils";
+import { getEventDisplayEndDate, getEventEndDate, getEventStartDate } from "@/lib/calendar-utils";
 import {
   isOrganizer,
   getUserParticipantId,
@@ -143,6 +143,8 @@ export function EventDetailPopover({
   const startDate = getEventStartDate(event);
   const durationMinutes = parseDuration(event.duration);
   const endDate = getEventEndDate(event);
+  const displayEndDate = getEventDisplayEndDate(event);
+  const isMultiDay = !isSameDay(startDate, displayEndDate);
 
   const locationName = useMemo(() => {
     if (!event.locations) return null;
@@ -331,16 +333,50 @@ export function EventDetailPopover({
         <div className="flex items-start gap-2.5">
           <Clock className="w-4 h-4 text-muted-foreground mt-0.5 flex-shrink-0" />
           <div className="text-sm">
-            <span className="font-medium text-foreground">
-              {formatEventDate(startDate)}
-            </span>
-            {event.showWithoutTime ? (
-              <span className="text-muted-foreground ml-1.5">{t("events.all_day")}</span>
+            {isMultiDay ? (
+              event.showWithoutTime ? (
+                <>
+                  <div className="font-medium text-foreground">
+                    {formatEventDate(startDate)} –
+                  </div>
+                  <div className="font-medium text-foreground">
+                    {formatEventDate(displayEndDate)}
+                  </div>
+                  <div className="text-muted-foreground">{t("events.all_day")}</div>
+                </>
+              ) : (
+                <>
+                  <div className="font-medium text-foreground">
+                    {formatEventDate(startDate)}
+                    <span className="ml-1.5 font-normal text-muted-foreground">
+                      {formatTime(startDate)}
+                    </span>
+                  </div>
+                  <div className="font-medium text-foreground">
+                    {formatEventDate(endDate)}
+                    <span className="ml-1.5 font-normal text-muted-foreground">
+                      {formatTime(endDate)}
+                    </span>
+                  </div>
+                  <div className="text-muted-foreground text-xs">
+                    ({formatDurationDisplay(durationMinutes)})
+                  </div>
+                </>
+              )
             ) : (
-              <div className="text-muted-foreground">
-                {formatTime(startDate)} – {formatTime(endDate)}
-                <span className="ml-1.5 text-xs">({formatDurationDisplay(durationMinutes)})</span>
-              </div>
+              <>
+                <span className="font-medium text-foreground">
+                  {formatEventDate(startDate)}
+                </span>
+                {event.showWithoutTime ? (
+                  <span className="text-muted-foreground ml-1.5">{t("events.all_day")}</span>
+                ) : (
+                  <div className="text-muted-foreground">
+                    {formatTime(startDate)} – {formatTime(endDate)}
+                    <span className="ml-1.5 text-xs">({formatDurationDisplay(durationMinutes)})</span>
+                  </div>
+                )}
+              </>
             )}
           </div>
         </div>
diff --git a/components/calendar/event-modal.tsx b/components/calendar/event-modal.tsx
index 1d815207..c0d7c87a 100644
--- a/components/calendar/event-modal.tsx
+++ b/components/calendar/event-modal.tsx
@@ -5,7 +5,7 @@ import { useTranslations } from "next-intl";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { X, Trash2, Check, Users, CalendarDays, Copy, Pencil, Clock, MapPin, Video, Repeat, Bell, AlignLeft, Plus } from "lucide-react";
-import { format, parseISO, addHours, addDays } from "date-fns";
+import { format, parseISO, addHours, addDays, isSameDay } from "date-fns";
 import type { CalendarEvent, Calendar, CalendarParticipant, CalendarEventAlert } from "@/lib/jmap/types";
 import { parseDuration, getEventColor } from "./event-card";
 import { buildAllDayDuration, getEventDisplayEndDate, getEventEndDate, getEventStartDate, getPrimaryCalendarId } from "@/lib/calendar-utils";
@@ -621,14 +621,42 @@ export function EventModal({
               </div>
             </div>
 
-            <div className="text-sm">
-              <span className="font-medium">{formatEventDate(startD)}</span>
-              {!event.showWithoutTime && (
-                <span className="text-muted-foreground ml-2">
-                  {format(startD, timeDisplayFmt)} – {format(endD, timeDisplayFmt)}
-                </span>
-              )}
-            </div>
+            {(() => {
+              const displayEnd = getEventDisplayEndDate(event);
+              const multiDay = !isSameDay(startD, displayEnd);
+              if (multiDay && event.showWithoutTime) {
+                return (
+                  <div className="text-sm">
+                    <div className="font-medium">{formatEventDate(startD)} –</div>
+                    <div className="font-medium">{formatEventDate(displayEnd)}</div>
+                  </div>
+                );
+              }
+              if (multiDay) {
+                return (
+                  <div className="text-sm">
+                    <div>
+                      <span className="font-medium">{formatEventDate(startD)}</span>
+                      <span className="text-muted-foreground ml-2">{format(startD, timeDisplayFmt)}</span>
+                    </div>
+                    <div>
+                      <span className="font-medium">{formatEventDate(endD)}</span>
+                      <span className="text-muted-foreground ml-2">{format(endD, timeDisplayFmt)}</span>
+                    </div>
+                  </div>
+                );
+              }
+              return (
+                <div className="text-sm">
+                  <span className="font-medium">{formatEventDate(startD)}</span>
+                  {!event.showWithoutTime && (
+                    <span className="text-muted-foreground ml-2">
+                      {format(startD, timeDisplayFmt)} – {format(endD, timeDisplayFmt)}
+                    </span>
+                  )}
+                </div>
+              );
+            })()}
 
             {event.description && (
               <p className="text-sm text-muted-foreground">{event.description}</p>
@@ -742,17 +770,55 @@ export function EventModal({
             <div className="flex items-start gap-2.5">
               <Clock className="w-4 h-4 text-muted-foreground mt-0.5 flex-shrink-0" />
               <div className="text-sm">
-                <span className="font-medium text-foreground">
-                  {formatEventDate(startD)}
-                </span>
-                {event.showWithoutTime ? (
-                  <span className="text-muted-foreground ml-1.5">{t("events.all_day")}</span>
-                ) : (
-                  <div className="text-muted-foreground">
-                    {format(startD, timeDisplayFmt)} – {format(endD, timeDisplayFmt)}
-                    <span className="ml-1.5 text-xs">({formatDurationDisplay(durMin)})</span>
-                  </div>
-                )}
+                {(() => {
+                  const displayEnd = getEventDisplayEndDate(event);
+                  const multiDay = !isSameDay(startD, displayEnd);
+                  if (multiDay && event.showWithoutTime) {
+                    return (
+                      <>
+                        <div className="font-medium text-foreground">{formatEventDate(startD)} –</div>
+                        <div className="font-medium text-foreground">{formatEventDate(displayEnd)}</div>
+                        <div className="text-muted-foreground">{t("events.all_day")}</div>
+                      </>
+                    );
+                  }
+                  if (multiDay) {
+                    return (
+                      <>
+                        <div className="font-medium text-foreground">
+                          {formatEventDate(startD)}
+                          <span className="ml-1.5 font-normal text-muted-foreground">
+                            {format(startD, timeDisplayFmt)}
+                          </span>
+                        </div>
+                        <div className="font-medium text-foreground">
+                          {formatEventDate(endD)}
+                          <span className="ml-1.5 font-normal text-muted-foreground">
+                            {format(endD, timeDisplayFmt)}
+                          </span>
+                        </div>
+                        <div className="text-muted-foreground text-xs">
+                          ({formatDurationDisplay(durMin)})
+                        </div>
+                      </>
+                    );
+                  }
+                  return (
+                    <>
+                      <span className="font-medium text-foreground">
+                        {formatEventDate(startD)}
+                      </span>
+                      {event.showWithoutTime ? (
+                        <span className="text-muted-foreground ml-1.5">{t("events.all_day")}</span>
+                      ) : (
+                        <div className="text-muted-foreground">
+                          {format(startD, timeDisplayFmt)} – {format(endD, timeDisplayFmt)}
+                          <span className="ml-1.5 text-xs">({formatDurationDisplay(durMin)})</span>
+                        </div>
+                      )}
+                    </>
+                  );
+                })()}
               </div>
             </div>
 
diff --git a/components/email/email-list-item.tsx b/components/email/email-list-item.tsx
index 2fdd4172..84813009 100644
--- a/components/email/email-list-item.tsx
+++ b/components/email/email-list-item.tsx
@@ -50,7 +50,9 @@ export function EmailListItem({ email, selected, onClick, onDoubleClick, onConte
   const currentMailboxRole = mailboxes.find(mb => mb.id === selectedMailbox)?.role;
   const showRecipient = currentMailboxRole === 'sent' || currentMailboxRole === 'drafts';
   const sender = showRecipient ? (email.to?.[0] ?? email.from?.[0]) : email.from?.[0];
-  const isFocusedMailLayout = mailLayout === 'focus';
+  const isMobile = useUIStore((state) => state.isMobile);
+  // The horizontal one-line "focus" layout doesn't fit on narrow screens; fall back to multi-line on mobile.
+  const isFocusedMailLayout = mailLayout === 'focus' && !isMobile;
   const hideJunkAvatarImages = currentMailboxRole === 'junk' && !showAvatarsInJunk;
   const trimmedPreview = stripInvisibleLeading(email.preview ?? '');
   const inlinePreview = showPreview && trimmedPreview ? ` ${trimmedPreview}` : '';
@@ -68,8 +70,6 @@ export function EmailListItem({ email, selected, onClick, onDoubleClick, onConte
     sourceMailboxId: selectedMailbox,
   });
 
-  const isMobile = useUIStore((state) => state.isMobile);
-
   const { onTouchStart, onTouchEnd, onTouchMove, onTouchCancel, isPressed } = useLongPress(
     useCallback((pos) => {
       onContextMenu?.(
diff --git a/components/email/email-list.tsx b/components/email/email-list.tsx
index 50f5aae5..80753f58 100644
--- a/components/email/email-list.tsx
+++ b/components/email/email-list.tsx
@@ -11,6 +11,7 @@ import { ConfirmDialog } from "@/components/ui/confirm-dialog";
 import { useEmailStore } from "@/stores/email-store";
 import { useAuthStore } from "@/stores/auth-store";
 import { useSettingsStore } from "@/stores/settings-store";
+import { useUIStore } from "@/stores/ui-store";
 import { groupEmailsByThread, sortThreadGroups } from "@/lib/thread-utils";
 import { useContextMenu } from "@/hooks/use-context-menu";
 import { useConfirmDialog } from "@/hooks/use-confirm-dialog";
@@ -121,9 +122,11 @@ export function EmailList({
   const density = useSettingsStore((state) => state.density);
   const showPreview = useSettingsStore((state) => state.showPreview);
   const mailLayout = useSettingsStore((state) => state.mailLayout);
-  const isFocusedMailLayout = mailLayout === 'focus';
   const footerHasMore = hasMore ?? hasMoreEmails;
   const footerIsLoadingMore = isLoadingMoreItems ?? isLoadingMore;
+  const isMobile = useUIStore((state) => state.isMobile);
+  // Match the list items: focus layout collapses to multi-line on mobile, so virtualizer estimates must match.
+  const isFocusedMailLayout = mailLayout === 'focus' && !isMobile;
 
   const estimateSize = useCallback(() => {
     if (isFocusedMailLayout) {
diff --git a/components/email/email-viewer.tsx b/components/email/email-viewer.tsx
index d93ab922..91c1f9b9 100644
--- a/components/email/email-viewer.tsx
+++ b/components/email/email-viewer.tsx
@@ -7,6 +7,7 @@ import { emailExportFilename, attachmentDownloadFilename, DEFAULT_EMAIL_TEMPLATE
 import { EML_IMPORT_ACCEPT, expandImportableEmails } from "@/lib/eml-import";
 import { EMAIL_IFRAME_SANITIZE_CONFIG, collapseBlockedImageContainers, escapeHtml, plainTextToSafeHtml, sanitizeEmailHtml, sanitizePlainTextRenderedHtml } from "@/lib/email-sanitization";
 import { hasMeaningfulHtmlBody } from "@/lib/signature-utils";
+import { withBasePath } from "@/lib/browser-navigation";
 import { Button } from "@/components/ui/button";
 import { Avatar } from "@/components/ui/avatar";
 import { formatFileSize, cn, buildMailboxTree, MailboxNode, formatDateTime, generateUUID } from "@/lib/utils";
@@ -76,6 +77,7 @@ import { useContactStore, getContactDisplayName, getContactPrimaryEmail } from "
 import { toast } from "@/stores/toast-store";
 import { useDeviceDetection } from "@/hooks/use-media-query";
 import { useAuthStore } from "@/stores/auth-store";
+import { useAccountStore } from "@/stores/account-store";
 import { useEmailStore } from "@/stores/email-store";
 import { useThemeStore } from "@/stores/theme-store";
 import { EmailIdentityBadge } from "./email-identity-badge";
@@ -954,6 +956,7 @@ export function EmailViewer({
   const { isTablet, isMobile } = useDeviceDetection();
   const { tabletListVisible } = useUIStore();
   const { identities, client, isDemoMode, activeAccountId } = useAuthStore();
+  const activeAccount = useAccountStore((s) => s.accounts.find((a) => a.id === activeAccountId));
   const promptForRescheduleDelayedUntil = useCallback((): string | null => {
     const value = window.prompt(t('reschedule_prompt'));
     if (!value) return null;
@@ -3301,9 +3304,9 @@ export function EmailViewer({
 
   if (!email) {
     if (isDemoMode) {
-      const logoSrc = resolvedTheme === 'dark'
+      const logoSrc = withBasePath(resolvedTheme === 'dark'
         ? '/branding/Bulwark_Logo_with_Lettering_White_and_Color.svg'
-        : '/branding/Bulwark_Logo_with_Lettering_Dark_Color.svg';
+        : '/branding/Bulwark_Logo_with_Lettering_Dark_Color.svg');
       return (
         <div className={cn("flex-1 flex flex-col items-center justify-center bg-gradient-to-br from-muted/30 to-muted/50", className)}>
           <div className="text-center p-8 max-w-md">
@@ -5384,10 +5387,12 @@ export function EmailViewer({
             <div className="flex items-start" style={{ gap: 'var(--density-item-gap)' }}>
               <div className="flex-shrink-0">
                 <Avatar
-                  name={currentUserName || "You"}
-                  email={currentUserEmail || ""}
+                  name={activeAccount?.displayName || currentUserName || "You"}
+                  email={activeAccount?.email || activeAccount?.username || currentUserEmail || ""}
                   size="lg"
                   className="shadow-sm w-10 h-10"
+                  disableFavicon
+                  fallbackColor={activeAccount?.avatarColor}
                 />
               </div>
               <div className="flex-1 min-w-0 space-y-3">
diff --git a/components/email/thread-list-item.tsx b/components/email/thread-list-item.tsx
index 68b17c40..11e84099 100644
--- a/components/email/thread-list-item.tsx
+++ b/components/email/thread-list-item.tsx
@@ -74,7 +74,9 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
     const getAccountById = useAccountStore((state) => state.getAccountById);
     const accountColor = email.accountId ? getAccountById(email.accountId)?.avatarColor : undefined;
     const isChecked = selectedEmailIds.has(email.id);
-    const isFocusedMailLayout = mailLayout === 'focus';
+    const isMobile = useUIStore((state) => state.isMobile);
+    // The horizontal one-line "focus" layout doesn't fit on narrow screens; fall back to multi-line on mobile.
+    const isFocusedMailLayout = mailLayout === 'focus' && !isMobile;
     const trimmedPreview = stripInvisibleLeading(email.preview ?? '');
     const inlinePreview = showPreview && trimmedPreview ? ` ${trimmedPreview}` : '';
     const scheduledSendLabel = email.isScheduled && email.scheduledSendAt
@@ -95,8 +97,6 @@ const SingleEmailItem = React.forwardRef<HTMLDivElement, SingleEmailItemProps>(
       sourceMailboxId: selectedMailbox,
     });
 
-    const isMobile = useUIStore((state) => state.isMobile);
-
     const { onTouchStart, onTouchEnd, onTouchMove, onTouchCancel, isPressed } = useLongPress(
       useCallback((pos) => {
         onContextMenu?.(
@@ -404,7 +404,8 @@ export const ThreadListItem = React.forwardRef<HTMLDivElement, ThreadListItemPro
     const showAvatarsInJunk = useSettingsStore((state) => state.showAvatarsInJunk);
     const isMobile = useUIStore((state) => state.isMobile);
     const { latestEmail, participantNames, hasUnread, hasStarred, hasAttachment, hasAnswered, hasForwarded, emailCount } = thread;
-    const isFocusedMailLayout = mailLayout === 'focus';
+    // The horizontal one-line "focus" layout doesn't fit on narrow screens; fall back to multi-line on mobile.
+    const isFocusedMailLayout = mailLayout === 'focus' && !isMobile;
     const trimmedPreview = stripInvisibleLeading(latestEmail.preview ?? '');
     const inlinePreview = showPreview && trimmedPreview ? ` ${trimmedPreview}` : '';
     const scheduledSendLabel = latestEmail.isScheduled && latestEmail.scheduledSendAt
diff --git a/components/layout/navigation-rail.tsx b/components/layout/navigation-rail.tsx
index 56a721d9..fc6649ff 100644
--- a/components/layout/navigation-rail.tsx
+++ b/components/layout/navigation-rail.tsx
@@ -21,7 +21,7 @@ import { getMaxAccounts } from "@/lib/account-utils";
 import { cn, formatFileSize } from "@/lib/utils";
 import { PluginSlot } from "@/components/plugins/plugin-slot";
 import { KeyboardShortcutsModal } from "@/components/keyboard-shortcuts-modal";
-import { apiFetch, getPathPrefix } from "@/lib/browser-navigation";
+import { apiFetch, getPathPrefix, withBasePath } from "@/lib/browser-navigation";
 import { Avatar } from "@/components/ui/avatar";
 
 interface NavItem {
@@ -444,7 +444,7 @@ export function NavigationRail({
       )}
     >
       {(() => {
-        const logoUrl = resolvedTheme === 'dark' ? (appLogoDarkUrl || appLogoLightUrl) : (appLogoLightUrl || appLogoDarkUrl);
+        const logoUrl = withBasePath(resolvedTheme === 'dark' ? (appLogoDarkUrl || appLogoLightUrl) : (appLogoLightUrl || appLogoDarkUrl));
         return logoUrl ? (
           <div className="flex items-center justify-center py-3 px-1">
             <img
diff --git a/components/layout/sidebar.tsx b/components/layout/sidebar.tsx
index 5d653e05..d76218f4 100644
--- a/components/layout/sidebar.tsx
+++ b/components/layout/sidebar.tsx
@@ -1,6 +1,6 @@
 "use client";
 
-import { useState, useEffect, ReactNode } from "react";
+import { useState, useEffect, useMemo, ReactNode } from "react";
 import { useTranslations } from "next-intl";
 import { useRouter } from "@/i18n/navigation";
 import { PluginSlot } from "@/components/plugins/plugin-slot";
@@ -736,15 +736,20 @@ export function Sidebar({
   // pane.
   const hideAccountSwitcher = useSettingsStore(s => s.hideAccountSwitcher) || isEmbedded;
   const enableUnifiedMailbox = useSettingsStore(s => s.enableUnifiedMailbox);
+  const includeGroupInUnified = useSettingsStore(s => s.includeGroupInUnified);
   const colorfulSidebarIcons = useSettingsStore(s => s.colorfulSidebarIcons);
   const tagCounts = useEmailStore(s => s.tagCounts);
   const accounts = useAccountStore(s => s.accounts);
   const connectedAccounts = accounts.filter(a => a.isConnected);
+  const hasGroupInboxes = useMemo(() => mailboxes.some(m => m.isShared), [mailboxes]);
   // Pro shell treats the unified mailbox as a core part of the multi-account
-  // UI, so it ignores the user-facing `enableUnifiedMailbox` toggle. The
-  // 2+ account requirement still applies - with a single account the
-  // unified counts would just duplicate that account's inbox.
-  const showUnified = (multiAccountMode || enableUnifiedMailbox) && connectedAccounts.length > 1;
+  // UI, so it ignores the user-facing `enableUnifiedMailbox` toggle. With a
+  // single account we still surface unified when the user has opted into
+  // merging group/shared inboxes — otherwise the counts would just duplicate
+  // the one inbox.
+  const showUnified =
+    (multiAccountMode || enableUnifiedMailbox) &&
+    (connectedAccounts.length > 1 || (includeGroupInUnified && hasGroupInboxes));
   const { unifiedCounts } = useEmailStore();
   const t = useTranslations('sidebar');
 
diff --git a/components/pwa-install-prompt.tsx b/components/pwa-install-prompt.tsx
index cb21f7e1..00c8bfb3 100644
--- a/components/pwa-install-prompt.tsx
+++ b/components/pwa-install-prompt.tsx
@@ -3,6 +3,7 @@
 import { useEffect, useState } from "react";
 import { X, Download } from "lucide-react";
 import { useConfig } from "@/hooks/use-config";
+import { withBasePath } from "@/lib/browser-navigation";
 
 interface BeforeInstallPromptEvent extends Event {
   prompt: () => Promise<void>;
@@ -58,7 +59,8 @@ export function PWAInstallPrompt() {
     return null;
   }
 
-  const logoSrc = appLogoLightUrl || faviconUrl;
+  const logoSrc = withBasePath(appLogoLightUrl || faviconUrl);
+  const darkLogoSrc = withBasePath(appLogoDarkUrl || faviconUrl);
 
   return (
     <div className="fixed bottom-4 right-4 z-50 bg-white dark:bg-neutral-900 rounded-lg shadow-lg border border-neutral-200 dark:border-neutral-800 p-4 max-w-sm animate-in slide-in-from-bottom-4">
@@ -75,7 +77,7 @@ export function PWAInstallPrompt() {
           )}
           {logoSrc && (
             <img
-              src={appLogoDarkUrl || faviconUrl}
+              src={darkLogoSrc}
               alt={appName}
               className="w-8 h-8 shrink-0 object-contain hidden dark:block"
             />
diff --git a/components/settings/calendar-settings.tsx b/components/settings/calendar-settings.tsx
index b8e655f8..4154f17b 100644
--- a/components/settings/calendar-settings.tsx
+++ b/components/settings/calendar-settings.tsx
@@ -4,17 +4,14 @@ import { useTranslations } from 'next-intl';
 import { useCalendarStore, CalendarViewMode } from '@/stores/calendar-store';
 import { useSettingsStore } from '@/stores/settings-store';
 import { usePolicyStore } from '@/stores/policy-store';
-import { SettingsSection, SettingItem, Select, RadioGroup, ToggleSwitch } from './settings-section';
+import { SettingsSection, SettingItem, Select, ToggleSwitch } from './settings-section';
 
 export function CalendarSettings() {
   const t = useTranslations('calendar.settings');
   const tViews = useTranslations('calendar.views');
-  const tDays = useTranslations('calendar.days');
 
   const { viewMode, setViewMode } = useCalendarStore();
   const {
-    timeFormat,
-    firstDayOfWeek,
     showTimeInMonthView,
     showWeekNumbers,
     enableCalendarTasks,
@@ -40,28 +37,6 @@ export function CalendarSettings() {
         />
       </SettingItem>
 
-      <SettingItem label={t('week_starts_on')}>
-        <Select
-          value={firstDayOfWeek.toString()}
-          onChange={(value) => updateSetting('firstDayOfWeek', parseInt(value) as 0 | 1)}
-          options={[
-            { value: '1', label: tDays('monday') },
-            { value: '0', label: tDays('sunday') },
-          ]}
-        />
-      </SettingItem>
-
-      <SettingItem label={t('time_format')}>
-        <RadioGroup
-          value={timeFormat}
-          onChange={(value) => updateSetting('timeFormat', value as '12h' | '24h')}
-          options={[
-            { value: '12h', label: t('time_format_12h') },
-            { value: '24h', label: t('time_format_24h') },
-          ]}
-        />
-      </SettingItem>
-
       <SettingItem
         label={t('show_time_in_month_view')}
         description={t('show_time_in_month_view_desc')}
diff --git a/components/settings/files-settings.tsx b/components/settings/files-settings.tsx
index 1bec3ddd..c686684a 100644
--- a/components/settings/files-settings.tsx
+++ b/components/settings/files-settings.tsx
@@ -6,6 +6,7 @@ import { Folder, FolderOpen, FileText, FileCode, ImageIcon, FileAudio, File, Hom
 import { SettingsSection, SettingItem, ToggleSwitch, RadioGroup } from "./settings-section";
 import { loadFilesSettings, saveFilesSettings, type FilesSettings, type FolderLayout } from "@/components/files/files-settings-dialog";
 import { cn } from "@/lib/utils";
+import { withBasePath } from "@/lib/browser-navigation";
 
 interface SampleFile {
   name: string;
@@ -95,7 +96,7 @@ function FilesSettingsPreview({ settings }: { settings: FilesSettings }) {
           )}
         >
           {settings.showThumbnails && file.thumbnailUrl ? (
-            <img src={file.thumbnailUrl} alt="" className="w-4 h-4 rounded object-cover flex-shrink-0" />
+            <img src={withBasePath(file.thumbnailUrl)} alt="" className="w-4 h-4 rounded object-cover flex-shrink-0" />
           ) : settings.showIcons ? (
             getPreviewIcon(file, settings.coloredIcons, "sm")
           ) : null}
@@ -125,7 +126,7 @@ function FilesSettingsPreview({ settings }: { settings: FilesSettings }) {
             )}
           >
             {settings.showThumbnails && file.thumbnailUrl ? (
-              <img src={file.thumbnailUrl} alt="" className="w-8 h-8 rounded object-cover flex-shrink-0" />
+              <img src={withBasePath(file.thumbnailUrl)} alt="" className="w-8 h-8 rounded object-cover flex-shrink-0" />
             ) : settings.showIcons ? (
               getPreviewIcon(file, settings.coloredIcons, "lg")
             ) : (
diff --git a/components/settings/language-settings.tsx b/components/settings/language-settings.tsx
index c8e22725..1a5cdf9d 100644
--- a/components/settings/language-settings.tsx
+++ b/components/settings/language-settings.tsx
@@ -1,17 +1,100 @@
 "use client";
 
+import { useMemo } from 'react';
 import { useTranslations } from 'next-intl';
 import { LanguageSwitcher } from '@/components/ui/language-switcher';
-import { SettingsSection, SettingItem } from './settings-section';
+import { useLocaleStore } from '@/stores/locale-store';
+import { useSettingsStore } from '@/stores/settings-store';
+import type { DateFormat, TimeFormat, FirstDayOfWeek } from '@/stores/settings-store';
+import { formatDate } from '@/lib/utils';
+import { SettingsSection, SettingItem, Select, RadioGroup } from './settings-section';
 
 export function LanguageSettings() {
-  const t = useTranslations('settings.appearance');
+  const t = useTranslations('settings.language_region');
+  const tDays = useTranslations('calendar.days');
+
+  const { dateFormat, timeFormat, firstDayOfWeek, updateSetting } = useSettingsStore();
+
+  // Subscribe to locale changes so the preview re-renders on language switch
+  // (formatDate reads it via getState() and would otherwise stay stale).
+  const locale = useLocaleStore((s) => s.locale);
+
+  const preview = useMemo(() => {
+    // Build sample timestamps for each bucket so users see what their pick
+    // will look like in practice. Use offsets relative to "now" so the
+    // bucketing is stable even though the wall-clock keeps moving.
+    void locale; void dateFormat; void timeFormat;
+    const now = new Date();
+    const today = new Date(now);
+    today.setHours(15, 31, 0, 0);
+    const thisWeek = new Date(now);
+    thisWeek.setDate(now.getDate() - 2);
+    thisWeek.setHours(15, 31, 0, 0);
+    const older = new Date(now);
+    older.setMonth(now.getMonth() - 2);
+    older.setHours(15, 31, 0, 0);
+    return {
+      today: formatDate(today),
+      thisWeek: formatDate(thisWeek),
+      older: formatDate(older),
+    };
+  }, [locale, dateFormat, timeFormat]);
 
   return (
-    <SettingsSection title={t('language.label')} description={t('language.description')}>
+    <SettingsSection title={t('title')} description={t('description')}>
       <SettingItem label={t('language.label')} description={t('language.description')}>
         <LanguageSwitcher />
       </SettingItem>
+
+      <SettingItem label={t('date_format.label')} description={t('date_format.description')}>
+        <div className="flex flex-col items-end gap-2">
+          <Select
+            value={dateFormat}
+            onChange={(value) => updateSetting('dateFormat', value as DateFormat)}
+            options={[
+              { value: 'smart', label: t('date_format.smart') },
+              { value: 'relative', label: t('date_format.relative') },
+              { value: 'full', label: t('date_format.full') },
+            ]}
+          />
+          <div className="text-xs text-muted-foreground text-right space-y-0.5 font-mono">
+            <div>
+              <span className="opacity-70">{t('date_format.preview_today')} </span>
+              <span className="text-foreground/90">{preview.today}</span>
+            </div>
+            <div>
+              <span className="opacity-70">{t('date_format.preview_this_week')} </span>
+              <span className="text-foreground/90">{preview.thisWeek}</span>
+            </div>
+            <div>
+              <span className="opacity-70">{t('date_format.preview_older')} </span>
+              <span className="text-foreground/90">{preview.older}</span>
+            </div>
+          </div>
+        </div>
+      </SettingItem>
+
+      <SettingItem label={t('time_format.label')} description={t('time_format.description')}>
+        <RadioGroup
+          value={timeFormat}
+          onChange={(value) => updateSetting('timeFormat', value as TimeFormat)}
+          options={[
+            { value: '12h', label: t('time_format.12h') },
+            { value: '24h', label: t('time_format.24h') },
+          ]}
+        />
+      </SettingItem>
+
+      <SettingItem label={t('first_day.label')} description={t('first_day.description')}>
+        <Select
+          value={firstDayOfWeek.toString()}
+          onChange={(value) => updateSetting('firstDayOfWeek', parseInt(value) as FirstDayOfWeek)}
+          options={[
+            { value: '1', label: tDays('monday') },
+            { value: '0', label: tDays('sunday') },
+          ]}
+        />
+      </SettingItem>
     </SettingsSection>
   );
 }
diff --git a/components/settings/layout-settings.tsx b/components/settings/layout-settings.tsx
index a3ac41c6..b4d08c4f 100644
--- a/components/settings/layout-settings.tsx
+++ b/components/settings/layout-settings.tsx
@@ -1,11 +1,13 @@
 "use client";
 
+import { useMemo } from 'react';
 import { useTranslations } from 'next-intl';
 import { useSettingsStore, type ToolbarPosition, type MailLayout } from '@/stores/settings-store';
 import { SettingsSection, SettingItem, RadioGroup, ToggleSwitch } from './settings-section';
 import { cn } from '@/lib/utils';
 import { usePolicyStore } from '@/stores/policy-store';
 import { useAccountStore } from '@/stores/account-store';
+import { useEmailStore } from '@/stores/email-store';
 
 const MAIL_LAYOUT_PREVIEW_ROWS = [
   { sender: 'Alice', subject: 'Quarterly roadmap', preview: 'The draft is ready for review.', selected: false },
@@ -115,9 +117,11 @@ function MailLayoutPreview({
 export function LayoutSettings() {
   const t = useTranslations('settings.appearance');
   const tEmail = useTranslations('settings.email_behavior');
-  const { toolbarPosition, showToolbarLabels, hideAccountSwitcher, showRailAccountList, enableUnifiedMailbox, colorfulSidebarIcons, mailLayout, proInterface, updateSetting } = useSettingsStore();
+  const { toolbarPosition, showToolbarLabels, hideAccountSwitcher, showRailAccountList, enableUnifiedMailbox, includeGroupInUnified, colorfulSidebarIcons, mailLayout, proInterface, updateSetting } = useSettingsStore();
   const { isSettingLocked, isSettingHidden } = usePolicyStore();
   const accounts = useAccountStore(s => s.accounts);
+  const mailboxes = useEmailStore(s => s.mailboxes);
+  const hasGroupInboxes = useMemo(() => mailboxes.some(m => m.isShared), [mailboxes]);
 
   return (
     <SettingsSection title={t('title')} description={t('description')}>
@@ -177,10 +181,11 @@ export function LayoutSettings() {
         />
       </SettingItem>
 
-      {accounts.length > 1 && (
+      {(accounts.length > 1 || hasGroupInboxes) && !isSettingHidden('enableUnifiedMailbox') && (
         <SettingItem
           label={t('unified_mailbox.label')}
           description={t('unified_mailbox.description')}
+          locked={isSettingLocked('enableUnifiedMailbox')}
         >
           <ToggleSwitch
             checked={enableUnifiedMailbox}
@@ -189,6 +194,21 @@ export function LayoutSettings() {
         </SettingItem>
       )}
 
+      {enableUnifiedMailbox && hasGroupInboxes && !isSettingHidden('includeGroupInUnified') && (
+        <div className="ml-4 border-l-2 border-border pl-4 -mt-2">
+          <SettingItem
+            label={t('unified_mailbox.include_group.label')}
+            description={t('unified_mailbox.include_group.description')}
+            locked={isSettingLocked('includeGroupInUnified')}
+          >
+            <ToggleSwitch
+              checked={includeGroupInUnified}
+              onChange={(v) => updateSetting('includeGroupInUnified', v)}
+            />
+          </SettingItem>
+        </div>
+      )}
+
       <SettingItem label={t('pro_interface.label')} description={t('pro_interface.description')}>
         <ToggleSwitch
           checked={proInterface}
diff --git a/components/ui/avatar.tsx b/components/ui/avatar.tsx
index 13ac7c20..315aa53e 100644
--- a/components/ui/avatar.tsx
+++ b/components/ui/avatar.tsx
@@ -6,6 +6,7 @@ import { useSettingsStore } from "@/stores/settings-store";
 import { useContactStore, getContactPhotoUri } from "@/stores/contact-store";
 import { useConfig } from "@/hooks/use-config";
 import { avatarHooks } from "@/lib/plugin-hooks";
+import { withBasePath } from "@/lib/browser-navigation";
 
 const IS_DEV = process.env.NODE_ENV !== "production";
 
@@ -236,7 +237,7 @@ export function Avatar({ name, email, contactPhotoUri, size = "md", className, d
   const customAvatar = devMode && email ? CUSTOM_AVATARS[email.toLowerCase()] : null;
   const pluginAvatar = pluginAvatarFailed ? null : pluginAvatarUrl;
   const photoSrc = resolvedContactPhoto || pluginAvatar || customAvatar || profilePic || null;
-  const faviconSrc = !imgError && !domainFailed && showFavicon ? `/api/favicon?domain=${encodeURIComponent(faviconDomain!)}` : null;
+  const faviconSrc = !imgError && !domainFailed && showFavicon ? withBasePath(`/api/favicon?domain=${encodeURIComponent(faviconDomain!)}`) : null;
   const imgSrc = disableImages ? null : (photoSrc || faviconSrc);
   const isFavicon = imgSrc !== null && imgSrc === faviconSrc;
 
diff --git a/hooks/use-mailbox-drop.ts b/hooks/use-mailbox-drop.ts
index 32026c7f..39bd7608 100644
--- a/hooks/use-mailbox-drop.ts
+++ b/hooks/use-mailbox-drop.ts
@@ -81,20 +81,8 @@ export function useMailboxDrop({ mailbox, onDropComplete, onSuccess, onError }:
     // Virtual nodes (shared folder headers) cannot be drop targets
     if (mailbox.id.startsWith("shared-")) return false;
 
-    // Shared (delegated) mailboxes still require the source to belong to the
-    // same delegating account. Real cross-account moves between primary
-    // accounts go through the cross-account path further down, but the
-    // shared-folder semantics here are about ACLs rather than transport, so
-    // they remain disallowed.
-    if (mailbox.isShared && draggedEmails[0]) {
-      const sourceMb = useEmailStore.getState().mailboxes.find(mb => mb.id === sourceMailboxId);
-      if (sourceMb?.accountId !== mailbox.accountId) {
-        return false;
-      }
-    }
-
     return true;
-  }, [isDragging, mailbox, sourceMailboxId, draggedEmails]);
+  }, [isDragging, mailbox, sourceMailboxId]);
 
   const handleDragOver = useCallback((e: DragEvent<HTMLDivElement>) => {
     e.preventDefault();
@@ -154,18 +142,38 @@ export function useMailboxDrop({ mailbox, onDropComplete, onSuccess, onError }:
         bySource.get(srcAccountId)!.push(id);
       }
 
+      // Decide whether to route via the cross-account (blob copy + import)
+      // pipeline. Two cases require it:
+      //   1. Destination is a delegated/shared mailbox whose owner JMAP
+      //      account differs from the source mailbox's JMAP account. There's
+      //      no atomic Email/set across accounts, even via the same client.
+      //   2. Destination is a primary mailbox on a different connected local
+      //      account than the source — the historical multi-account case.
+      const sourceMb = useEmailStore.getState().mailboxes.find(mb => mb.id === sourceMailboxId);
+      const sourceJmapAccountId = sourceMb?.accountId;
+      const destJmapAccountId = mailbox.accountId;
       const sourceAccountIds = Array.from(bySource.keys());
-      const isCrossAccount =
-        !!destAccountId &&
+
+      const isJmapCrossAccount =
+        !!sourceJmapAccountId &&
+        !!destJmapAccountId &&
+        sourceJmapAccountId !== destJmapAccountId;
+      const isLocalCrossAccount =
         !mailbox.isShared &&
+        !!destAccountId &&
         sourceAccountIds.some((src) => src !== destAccountId);
+      const isCrossAccount = isJmapCrossAccount || isLocalCrossAccount;
 
       if (isCrossAccount) {
-        // JMAP can't natively move an email between primary accounts, so the
-        // store reuploads each source blob into the destination account and
-        // then deletes the original.
+        if (!destAccountId) {
+          throw new Error('Could not resolve destination account');
+        }
+        // For a shared destination there is no separately-connected client
+        // for the owner; we reuse the viewing user's client but tell the
+        // import call to target the owner's JMAP account.
         const jmapDestId = mailbox.originalId || mailbox.id;
-        await crossAccountMoveEmails(bySource, destAccountId, jmapDestId);
+        const destJmapOverride = mailbox.isShared ? mailbox.accountId : undefined;
+        await crossAccountMoveEmails(bySource, destAccountId, jmapDestId, destJmapOverride);
       } else {
         // Single-account or same-account-shared move: bulk JMAP request.
         await moveEmailsToMailbox(client, emailIds, mailbox.id);
diff --git a/i18n/routing.ts b/i18n/routing.ts
index 8bea497e..ad420514 100644
--- a/i18n/routing.ts
+++ b/i18n/routing.ts
@@ -12,9 +12,21 @@ const localePrefix = (process.env.NEXT_PUBLIC_LOCALE_PREFIX ?? 'never') as
   | 'always'
   | 'as-needed';
 
+const SUPPORTED_LOCALES = ['cs', 'da', 'de', 'en', 'es', 'fr', 'it', 'ja', 'ko', 'lv', 'nl', 'pl', 'pt', 'ru', 'tr', 'uk', 'zh'] as const;
+
+// Fallback locale used when the visitor's Accept-Language header does not
+// match any supported locale (and no NEXT_LOCALE cookie is set yet). Admins
+// set this via NEXT_PUBLIC_DEFAULT_LOCALE at build time to localise greenfield
+// deployments without having every user change their preference manually.
+const envDefaultLocale = process.env.NEXT_PUBLIC_DEFAULT_LOCALE?.trim();
+const resolvedDefaultLocale =
+  envDefaultLocale && (SUPPORTED_LOCALES as readonly string[]).includes(envDefaultLocale)
+    ? (envDefaultLocale as (typeof SUPPORTED_LOCALES)[number])
+    : 'en';
+
 export const routing = defineRouting({
-  locales: ['cs', 'da', 'de', 'en', 'es', 'fr', 'it', 'ja', 'ko', 'lv', 'nl', 'pl', 'pt', 'ru', 'tr', 'uk', 'zh'],
-  defaultLocale: 'en',
+  locales: SUPPORTED_LOCALES,
+  defaultLocale: resolvedDefaultLocale,
   localePrefix
 });
 
diff --git a/lib/browser-navigation.ts b/lib/browser-navigation.ts
index 5df6ff91..15369273 100644
--- a/lib/browser-navigation.ts
+++ b/lib/browser-navigation.ts
@@ -75,6 +75,26 @@ export function apiFetch(input: string, init?: RequestInit): Promise<Response> {
   return fetch(input, init);
 }
 
+/**
+ * Mount-prefix-aware wrapper for URL strings used in `<img src>`, `<link href>`,
+ * `window.location.*`, etc. — anything the browser resolves itself, where
+ * `apiFetch` can't help.
+ *
+ * Idempotent: passing an already-prefixed value, an external URL, a
+ * protocol-relative URL, or an empty/falsy value returns it unchanged. So it's
+ * safe to wrap admin-configurable values that might be either a local path
+ * (`/branding/foo.svg`, `/api/admin/branding/...`) or a full URL.
+ */
+export function withBasePath(url: string | null | undefined): string {
+  if (!url) return url ?? '';
+  if (url.charCodeAt(0) !== 47) return url;        // not absolute (e.g. https://, data:, blob:)
+  if (url.charCodeAt(1) === 47) return url;        // protocol-relative //cdn...
+  const prefix = getPathPrefix();
+  if (!prefix) return url;
+  if (url === prefix || url.startsWith(prefix + '/')) return url;
+  return prefix + url;
+}
+
 
 /**
  * Extracts the locale from the current URL, skipping any mount prefix.
diff --git a/lib/jmap/client-interface.ts b/lib/jmap/client-interface.ts
index 7bd23ba1..ccac56ec 100644
--- a/lib/jmap/client-interface.ts
+++ b/lib/jmap/client-interface.ts
@@ -283,6 +283,6 @@ export interface IJMAPClient {
   copyFileNode(id: string, newName: string, parentId: string | null): Promise<FileNode>;
 
   // ── S/MIME raw-email helpers ──────────────────────────────────
-  importRawEmail(blob: Blob, mailboxIds: Record<string, boolean>, keywords?: Record<string, boolean>): Promise<string>;
+  importRawEmail(blob: Blob, mailboxIds: Record<string, boolean>, keywords?: Record<string, boolean>, accountId?: string): Promise<string>;
   submitEmail(emailId: string, identityId: string): Promise<void>;
 }
diff --git a/lib/jmap/client.ts b/lib/jmap/client.ts
index ed1f6b55..d06b7f41 100644
--- a/lib/jmap/client.ts
+++ b/lib/jmap/client.ts
@@ -2871,7 +2871,7 @@ export class JMAPClient implements IJMAPClient {
     }
   }
 
-  async uploadBlob(file: File): Promise<{ blobId: string; size: number; type: string }> {
+  async uploadBlob(file: File, accountId?: string): Promise<{ blobId: string; size: number; type: string }> {
     if (!this.session) {
       throw new Error('Not connected. Call connect() first.');
     }
@@ -2881,7 +2881,8 @@ export class JMAPClient implements IJMAPClient {
       throw new Error('Upload URL not available');
     }
 
-    const finalUploadUrl = uploadUrl.replace('{accountId}', encodeURIComponent(this.accountId));
+    const targetAccountId = accountId || this.accountId;
+    const finalUploadUrl = uploadUrl.replace('{accountId}', encodeURIComponent(targetAccountId));
     const response = await this.authenticatedFetch(finalUploadUrl, {
       method: 'POST',
       headers: { 'Content-Type': file.type || 'application/octet-stream' },
@@ -2911,7 +2912,7 @@ export class JMAPClient implements IJMAPClient {
     }
 
     // Nested format: { [accountId]: { blobId, type, size } }
-    const blobInfo = result[this.accountId];
+    const blobInfo = result[targetAccountId];
     if (blobInfo?.blobId) {
       return {
         blobId: blobInfo.blobId,
@@ -5464,20 +5465,29 @@ export class JMAPClient implements IJMAPClient {
     return response.arrayBuffer();
   }
 
-  /** Import a raw MIME message blob into the account. */
+  /**
+   * Import a raw MIME message blob into the account. Pass `accountId` to
+   * target a delegated account the caller has rights on (e.g. importing into
+   * a shared mailbox owned by another user). When omitted, falls back to the
+   * client's own primary account.
+   */
   async importRawEmail(
     blob: Blob,
     mailboxIds: Record<string, boolean>,
     keywords?: Record<string, boolean>,
+    accountId?: string,
   ): Promise<string> {
-    // First upload the blob
+    const targetAccountId = accountId || this.accountId;
+    // First upload the blob. Blob uploads are scoped to an account too —
+    // when importing into a delegated account, upload there so the resulting
+    // blobId is visible to Email/import on that account.
     const file = new File([blob], 'message.eml', { type: 'message/rfc822' });
-    const { blobId } = await this.uploadBlob(file);
+    const { blobId } = await this.uploadBlob(file, targetAccountId);
 
     // Then import via Email/import
     const response = await this.request([
       ['Email/import', {
-        accountId: this.accountId,
+        accountId: targetAccountId,
         emails: {
           'smime-import': {
             blobId,
diff --git a/lib/unified-mailbox.ts b/lib/unified-mailbox.ts
index f1f38649..1b3a1f8e 100644
--- a/lib/unified-mailbox.ts
+++ b/lib/unified-mailbox.ts
@@ -6,6 +6,11 @@ export interface UnifiedAccountClient {
   accountLabel: string;
   client: IJMAPClient;
   mailboxes: Mailbox[];
+  // When true, this entry represents a group/shared account owned by
+  // `accountId` but accessed through someone else's `client`. JMAP requests
+  // must use the mailbox's `originalId` and explicitly target this accountId
+  // so the server routes to the owner's data.
+  isShared?: boolean;
 }
 
 export interface UnifiedFetchResult {
@@ -60,10 +65,11 @@ export async function fetchUnifiedEmails(
       const mailbox = findMailboxByRole(account.mailboxes, role);
       if (!mailbox) return null;
 
+      const { jmapMailboxId, jmapAccountId } = resolveJmapTarget(account, mailbox);
       try {
         const result = await account.client.getEmails(
-          mailbox.id,
-          undefined,
+          jmapMailboxId,
+          jmapAccountId,
           limit,
           position,
         );
@@ -131,7 +137,8 @@ export async function searchUnifiedEmails(
   position: number,
 ): Promise<UnifiedFetchResult> {
   return fanOutUnifiedQuery(accounts, role, async (account, mailbox) => {
-    return account.client.searchEmails(query, mailbox.id, undefined, limit, position);
+    const { jmapMailboxId, jmapAccountId } = resolveJmapTarget(account, mailbox);
+    return account.client.searchEmails(query, jmapMailboxId, jmapAccountId, limit, position);
   });
 }
 
@@ -149,10 +156,31 @@ export async function advancedSearchUnifiedEmails(
   position: number,
 ): Promise<UnifiedFetchResult> {
   return fanOutUnifiedQuery(accounts, role, async (account, mailbox) => {
-    return account.client.advancedSearchEmails(filterFor(mailbox.id), undefined, limit, position);
+    const { jmapMailboxId, jmapAccountId } = resolveJmapTarget(account, mailbox);
+    return account.client.advancedSearchEmails(filterFor(jmapMailboxId), jmapAccountId, limit, position);
   });
 }
 
+/**
+ * Resolves the JMAP-side mailbox id and accountId for a mailbox living inside
+ * a UnifiedAccountClient. For personal-account entries we use the JMAP id as
+ * returned by the primary client; for shared-owner entries the mailbox id is
+ * namespaced (`${ownerId}:${origId}`) so we must use `originalId` and pass the
+ * owner's accountId through the request.
+ */
+function resolveJmapTarget(
+  account: UnifiedAccountClient,
+  mailbox: Mailbox,
+): { jmapMailboxId: string; jmapAccountId: string | undefined } {
+  if (account.isShared) {
+    return {
+      jmapMailboxId: mailbox.originalId ?? mailbox.id,
+      jmapAccountId: account.accountId,
+    };
+  }
+  return { jmapMailboxId: mailbox.id, jmapAccountId: undefined };
+}
+
 async function fanOutUnifiedQuery(
   accounts: UnifiedAccountClient[],
   role: UnifiedMailboxRole,
diff --git a/lib/utils.ts b/lib/utils.ts
index d6bd9371..9c623d27 100644
--- a/lib/utils.ts
+++ b/lib/utils.ts
@@ -3,6 +3,8 @@ import { twMerge } from "tailwind-merge";
 import { Mailbox, UNIFIED_MAILBOX_IDS } from "./jmap/types";
 import type { UnifiedMailboxRole } from "./jmap/types";
 import { debug } from "./debug";
+import { useLocaleStore } from "@/stores/locale-store";
+import { useSettingsStore } from "@/stores/settings-store";
 
 export function cn(...inputs: ClassValue[]) {
   return twMerge(clsx(inputs));
@@ -40,24 +42,86 @@ export function generateUUID(): string {
   return `${hex.slice(0, 8)}-${hex.slice(8, 12)}-${hex.slice(12, 16)}-${hex.slice(16, 20)}-${hex.slice(20)}`;
 }
 
+/**
+ * Formats a received-at date for the email list. The output style is
+ * controlled by the `dateFormat` user setting:
+ *
+ *   - `smart` (default) — locale-aware, age-bucketed:
+ *       today        → time only           ("15:31" or "3:31 PM")
+ *       last 7 days  → short weekday+time  ("Fr 15:31", "Fri 3:31 PM")
+ *       older        → full locale date    ("28.04.2026", "04/28/2026")
+ *   - `relative` — legacy en-US relative format ("1h ago", "2d ago").
+ *   - `full` — always the full locale date+time.
+ *
+ * Both the locale (from the language picker) and 12h/24h preference are
+ * read via `getState()` so this stays SSR-safe.
+ */
 export function formatDate(date: Date | string): string {
   const d = typeof date === "string" ? new Date(date) : date;
   const now = new Date();
-  const diff = now.getTime() - d.getTime();
 
-  const minutes = Math.floor(diff / 60000);
-  const hours = Math.floor(diff / 3600000);
-  const days = Math.floor(diff / 86400000);
+  const localeRaw = useLocaleStore.getState().locale;
+  const locale = localeRaw && localeRaw.length > 0 ? localeRaw : "en";
+  // `en` alone resolves to en-US in Intl; everything else uses the language
+  // subtag as-is and lets the runtime pick a sensible default region.
+  const intlLocale = locale === "en" ? "en-US" : locale;
+  const { dateFormat, timeFormat } = useSettingsStore.getState();
+  const hour12 = timeFormat === "12h";
 
-  if (minutes < 1) return "Just now";
-  if (minutes < 60) return `${minutes}m ago`;
-  if (hours < 24) return `${hours}h ago`;
-  if (days < 7) return `${days}d ago`;
+  if (dateFormat === "relative") {
+    const diff = now.getTime() - d.getTime();
+    const minutes = Math.floor(diff / 60000);
+    const hours = Math.floor(diff / 3600000);
+    const days = Math.floor(diff / 86400000);
+    if (minutes < 1) return "Just now";
+    if (minutes < 60) return `${minutes}m ago`;
+    if (hours < 24) return `${hours}h ago`;
+    if (days < 7) return `${days}d ago`;
+    return d.toLocaleDateString(intlLocale, {
+      month: "short",
+      day: "numeric",
+      year: d.getFullYear() !== now.getFullYear() ? "numeric" : undefined,
+    });
+  }
 
-  return d.toLocaleDateString("en-US", {
-    month: "short",
-    day: "numeric",
-    year: d.getFullYear() !== now.getFullYear() ? "numeric" : undefined,
+  if (dateFormat === "full") {
+    return d.toLocaleString(intlLocale, {
+      year: "numeric",
+      month: "2-digit",
+      day: "2-digit",
+      hour: "2-digit",
+      minute: "2-digit",
+      hour12,
+    });
+  }
+
+  // 'smart' (default)
+  const timeStr = d.toLocaleTimeString(intlLocale, {
+    hour: "2-digit",
+    minute: "2-digit",
+    hour12,
+  });
+
+  const isSameDay =
+    d.getFullYear() === now.getFullYear() &&
+    d.getMonth() === now.getMonth() &&
+    d.getDate() === now.getDate();
+  if (isSameDay) return timeStr;
+
+  const daysAgo = Math.floor((now.getTime() - d.getTime()) / 86400000);
+  if (daysAgo < 7) {
+    // German Intl outputs "Fr." with a trailing dot for `weekday: 'short'`;
+    // strip it so the result reads cleanly next to the time.
+    const weekday = d
+      .toLocaleDateString(intlLocale, { weekday: "short" })
+      .replace(/\.$/, "");
+    return `${weekday} ${timeStr}`;
+  }
+
+  return d.toLocaleDateString(intlLocale, {
+    year: "numeric",
+    month: "2-digit",
+    day: "2-digit",
   });
 }
 
diff --git a/lib/webdav/client.ts b/lib/webdav/client.ts
index 2772d37d..05486798 100644
--- a/lib/webdav/client.ts
+++ b/lib/webdav/client.ts
@@ -4,6 +4,7 @@
  */
 
 import { getActiveAccountSlotHeaders } from '@/lib/auth/active-account-slot';
+import { apiFetch, withBasePath } from '@/lib/browser-navigation';
 
 export interface WebDAVResource {
   href: string;
@@ -32,7 +33,7 @@ export class WebDAVClient {
       ...options?.headers,
     };
 
-    return fetch(this.proxyUrl, {
+    return apiFetch(this.proxyUrl, {
       method: 'POST',
       headers,
       body: options?.body,
@@ -118,7 +119,7 @@ export class WebDAVClient {
       // Use XMLHttpRequest for progress tracking
       return new Promise((resolve, reject) => {
         const xhr = new XMLHttpRequest();
-        xhr.open('POST', this.proxyUrl);
+        xhr.open('POST', withBasePath(this.proxyUrl));
         xhr.setRequestHeader('X-WebDAV-Method', 'PUT');
         xhr.setRequestHeader('X-WebDAV-Path', path);
         const slotHeaders = getActiveAccountSlotHeaders();
diff --git a/locales/cs/common.json b/locales/cs/common.json
index 4b0db34f..6a989409 100644
--- a/locales/cs/common.json
+++ b/locales/cs/common.json
@@ -784,7 +784,7 @@
     "keep_editing": "Pokračovat v úpravách",
     "tabs": {
       "appearance": "Vzhled",
-      "language": "Jazyk a region",
+      "language": "Jazyk, region a čas",
       "email": "Chování e-mailu",
       "composer": "Psaní zpráv",
       "privacy": "Soukromí a bezpečnost",
@@ -876,7 +876,11 @@
       },
       "unified_mailbox": {
         "label": "Sjednocená schránka",
-        "description": "Zobrazovat sloučené složky (Doručené, Odeslané atd.) ze všech připojených účtů"
+        "description": "Zobrazovat sloučené složky (Doručené, Odeslané atd.) ze všech připojených účtů",
+        "include_group": {
+          "label": "Zahrnout skupinové schránky",
+          "description": "Zahrnout do sjednoceného zobrazení také sdílené/skupinové schránky."
+        }
       },
       "colorful_sidebar_icons": {
         "label": "Barevné ikony postranního panelu",
@@ -960,8 +964,8 @@
       }
     },
     "language_region": {
-      "title": "Jazyk a region",
-      "description": "Nakonfigurujte jazykové a místní předvolby",
+      "title": "Jazyk, region a čas",
+      "description": "Jazyk, formát data, formát času a další regionální předvolby",
       "language": {
         "label": "Jazyk",
         "description": "Vyberte preferovaný jazyk",
@@ -970,10 +974,13 @@
       },
       "date_format": {
         "label": "Formát data",
-        "description": "Jak se mají zobrazovat data",
-        "regional": "Místní",
-        "iso": "ISO 8601",
-        "custom": "Vlastní"
+        "description": "Jak se zobrazují data v seznamu e-mailů",
+        "smart": "Chytrý (regionální)",
+        "relative": "Relativní (před 1 h, před 2 d)",
+        "full": "Vždy úplné datum",
+        "preview_today": "Dnes:",
+        "preview_this_week": "Tento týden:",
+        "preview_older": "Starší:"
       },
       "time_format": {
         "label": "Formát času",
diff --git a/locales/da/common.json b/locales/da/common.json
index 4990ccf8..5adbe4f2 100644
--- a/locales/da/common.json
+++ b/locales/da/common.json
@@ -785,7 +785,7 @@
     "search_no_results": "Ingen match i indstillinger",
     "tabs": {
       "appearance": "Udseende",
-      "language": "Sprog & region",
+      "language": "Sprog, region & tid",
       "email": "E-mail-adfærd",
       "composer": "Komponist",
       "privacy": "Privatliv & sikkerhed",
@@ -877,7 +877,11 @@
       },
       "unified_mailbox": {
         "label": "Samlet postkasse",
-        "description": "Vis samlede mapper (Indbakke, Sendt osv.) på tværs af alle tilknyttede konti"
+        "description": "Vis samlede mapper (Indbakke, Sendt osv.) på tværs af alle tilknyttede konti",
+        "include_group": {
+          "label": "Inkluder gruppepostkasser",
+          "description": "Inkluder også delte/gruppepostkasser i den samlede visning."
+        }
       },
       "colorful_sidebar_icons": {
         "label": "Farverige sidepane-ikoner",
@@ -961,8 +965,8 @@
       }
     },
     "language_region": {
-      "title": "Sprog & region",
-      "description": "Konfigurér sprog og regionale præferencer",
+      "title": "Sprog, region & tid",
+      "description": "Sprog, datoformat, tidsformat og andre regionale indstillinger",
       "language": {
         "label": "Sprog",
         "description": "Vælg dit foretrukne sprog",
@@ -971,10 +975,13 @@
       },
       "date_format": {
         "label": "Datoformat",
-        "description": "Hvordan datoer skal vises",
-        "regional": "Regionalt",
-        "iso": "ISO 8601",
-        "custom": "Brugerdefineret"
+        "description": "Sådan vises datoer på e-mail-listen",
+        "smart": "Smart (regionalt)",
+        "relative": "Relativ (for 1 t siden, for 2 d siden)",
+        "full": "Altid fuld dato",
+        "preview_today": "I dag:",
+        "preview_this_week": "Denne uge:",
+        "preview_older": "Ældre:"
       },
       "time_format": {
         "label": "Tidsformat",
diff --git a/locales/de/common.json b/locales/de/common.json
index 7b0c2304..e80b5bd3 100644
--- a/locales/de/common.json
+++ b/locales/de/common.json
@@ -784,7 +784,7 @@
     "keep_editing": "Weiter bearbeiten",
     "tabs": {
       "appearance": "Darstellung",
-      "language": "Sprache & Region",
+      "language": "Sprache, Region & Zeit",
       "email": "E-Mail-Verhalten",
       "composer": "Editor",
       "privacy": "Datenschutz & Sicherheit",
@@ -876,7 +876,11 @@
       },
       "unified_mailbox": {
         "label": "Gemeinsames Postfach",
-        "description": "Kombinierte Ordner (Posteingang, Gesendet usw.) für alle verbundenen Konten anzeigen"
+        "description": "Kombinierte Ordner (Posteingang, Gesendet usw.) für alle verbundenen Konten anzeigen",
+        "include_group": {
+          "label": "Gruppenpostfächer einbeziehen",
+          "description": "Gemeinsam genutzte/Gruppenpostfächer ebenfalls in die vereinheitlichte Ansicht aufnehmen."
+        }
       },
       "colorful_sidebar_icons": {
         "label": "Farbige Seitenleistensymbole",
@@ -960,8 +964,8 @@
       }
     },
     "language_region": {
-      "title": "Sprache & Region",
-      "description": "Konfigurieren Sie Sprach- und Regionaleinstellungen",
+      "title": "Sprache, Region & Zeit",
+      "description": "Sprache, Datums- und Zeitformat sowie weitere regionale Einstellungen",
       "language": {
         "label": "Sprache",
         "description": "Wählen Sie Ihre bevorzugte Sprache",
@@ -970,10 +974,13 @@
       },
       "date_format": {
         "label": "Datumsformat",
-        "description": "Wie Daten angezeigt werden sollen",
-        "regional": "Regional",
-        "iso": "ISO 8601",
-        "custom": "Benutzerdefiniert"
+        "description": "Wie Daten in der E-Mail-Liste angezeigt werden",
+        "smart": "Intelligent (gebietsschemaabhängig)",
+        "relative": "Relativ (vor 1 Std., vor 2 Tagen)",
+        "full": "Immer vollständiges Datum",
+        "preview_today": "Heute:",
+        "preview_this_week": "Diese Woche:",
+        "preview_older": "Älter:"
       },
       "time_format": {
         "label": "Zeitformat",
diff --git a/locales/en/common.json b/locales/en/common.json
index 573d7a7d..a7d3a38c 100644
--- a/locales/en/common.json
+++ b/locales/en/common.json
@@ -785,7 +785,7 @@
     "search_no_results": "No matching settings",
     "tabs": {
       "appearance": "Appearance",
-      "language": "Language & Region",
+      "language": "Language, Region & Time",
       "email": "Email Behavior",
       "composer": "Composer",
       "privacy": "Privacy & Security",
@@ -877,7 +877,11 @@
       },
       "unified_mailbox": {
         "label": "Unified Mailbox",
-        "description": "Show combined folders (Inbox, Sent, etc.) across all connected accounts"
+        "description": "Show combined folders (Inbox, Sent, etc.) across all connected accounts",
+        "include_group": {
+          "label": "Include group inboxes",
+          "description": "Also merge shared/group inboxes into the unified view."
+        }
       },
       "colorful_sidebar_icons": {
         "label": "Colorful Sidebar Icons",
@@ -961,8 +965,8 @@
       }
     },
     "language_region": {
-      "title": "Language & Region",
-      "description": "Configure language and regional preferences",
+      "title": "Language, Region & Time",
+      "description": "Language, date format, time format, and other regional preferences",
       "language": {
         "label": "Language",
         "description": "Choose your preferred language",
@@ -971,10 +975,13 @@
       },
       "date_format": {
         "label": "Date Format",
-        "description": "How dates should be displayed",
-        "regional": "Regional",
-        "iso": "ISO 8601",
-        "custom": "Custom"
+        "description": "How dates are shown in the email list",
+        "smart": "Smart (locale-aware)",
+        "relative": "Relative (1h ago, 2d ago)",
+        "full": "Always full date",
+        "preview_today": "Today:",
+        "preview_this_week": "This week:",
+        "preview_older": "Older:"
       },
       "time_format": {
         "label": "Time Format",
diff --git a/locales/es/common.json b/locales/es/common.json
index 575f0ac5..e81aaccf 100644
--- a/locales/es/common.json
+++ b/locales/es/common.json
@@ -784,7 +784,7 @@
     "keep_editing": "Seguir editando",
     "tabs": {
       "appearance": "Apariencia",
-      "language": "Idioma y Región",
+      "language": "Idioma, Región y Hora",
       "email": "Comportamiento del Correo",
       "composer": "Editor",
       "privacy": "Privacidad y Seguridad",
@@ -876,7 +876,11 @@
       },
       "unified_mailbox": {
         "label": "Buzón unificado",
-        "description": "Mostrar carpetas combinadas (Entrada, Enviados, etc.) de todas las cuentas conectadas"
+        "description": "Mostrar carpetas combinadas (Entrada, Enviados, etc.) de todas las cuentas conectadas",
+        "include_group": {
+          "label": "Incluir buzones de grupo",
+          "description": "Incluir también los buzones compartidos o de grupo en la vista unificada."
+        }
       },
       "colorful_sidebar_icons": {
         "label": "Iconos de barra lateral a color",
@@ -960,8 +964,8 @@
       }
     },
     "language_region": {
-      "title": "Idioma y Región",
-      "description": "Configure las preferencias de idioma y región",
+      "title": "Idioma, Región y Hora",
+      "description": "Idioma, formato de fecha, formato de hora y otras preferencias regionales",
       "language": {
         "label": "Idioma",
         "description": "Elija su idioma preferido",
@@ -970,10 +974,13 @@
       },
       "date_format": {
         "label": "Formato de Fecha",
-        "description": "Cómo se deben mostrar las fechas",
-        "regional": "Regional",
-        "iso": "ISO 8601",
-        "custom": "Personalizado"
+        "description": "Cómo se muestran las fechas en la lista de correos",
+        "smart": "Inteligente (según región)",
+        "relative": "Relativo (hace 1 h, hace 2 d)",
+        "full": "Fecha completa siempre",
+        "preview_today": "Hoy:",
+        "preview_this_week": "Esta semana:",
+        "preview_older": "Más antiguo:"
       },
       "time_format": {
         "label": "Formato de Hora",
diff --git a/locales/fr/common.json b/locales/fr/common.json
index db258bd6..8b26ae0c 100644
--- a/locales/fr/common.json
+++ b/locales/fr/common.json
@@ -784,7 +784,7 @@
     "keep_editing": "Continuer l'édition",
     "tabs": {
       "appearance": "Apparence",
-      "language": "Langue et région",
+      "language": "Langue, région et heure",
       "email": "Comportement email",
       "composer": "Compositeur",
       "privacy": "Confidentialité et sécurité",
@@ -876,7 +876,11 @@
       },
       "unified_mailbox": {
         "label": "Boîte aux lettres unifiée",
-        "description": "Afficher les dossiers combinés (Réception, Envoyés, etc.) de tous les comptes connectés"
+        "description": "Afficher les dossiers combinés (Réception, Envoyés, etc.) de tous les comptes connectés",
+        "include_group": {
+          "label": "Inclure les boîtes de groupe",
+          "description": "Inclure également les boîtes partagées ou de groupe dans la vue unifiée."
+        }
       },
       "colorful_sidebar_icons": {
         "label": "Icônes colorées dans la barre latérale",
@@ -960,8 +964,8 @@
       }
     },
     "language_region": {
-      "title": "Langue et région",
-      "description": "Configurez vos préférences linguistiques et régionales",
+      "title": "Langue, région et heure",
+      "description": "Langue, format de date, format d'heure et autres préférences régionales",
       "language": {
         "label": "Langue",
         "description": "Choisissez votre langue préférée",
@@ -970,10 +974,13 @@
       },
       "date_format": {
         "label": "Format de date",
-        "description": "Comment les dates doivent être affichées",
-        "regional": "Régional",
-        "iso": "ISO 8601",
-        "custom": "Personnalisé"
+        "description": "Comment les dates apparaissent dans la liste des e-mails",
+        "smart": "Intelligent (adapté à la région)",
+        "relative": "Relatif (il y a 1 h, il y a 2 j)",
+        "full": "Toujours la date complète",
+        "preview_today": "Aujourd'hui :",
+        "preview_this_week": "Cette semaine :",
+        "preview_older": "Plus ancien :"
       },
       "time_format": {
         "label": "Format d'heure",
diff --git a/locales/it/common.json b/locales/it/common.json
index 83e6ae38..4eaa318b 100644
--- a/locales/it/common.json
+++ b/locales/it/common.json
@@ -784,7 +784,7 @@
     "keep_editing": "Continua a modificare",
     "tabs": {
       "appearance": "Aspetto",
-      "language": "Lingua e regione",
+      "language": "Lingua, regione e ora",
       "email": "Comportamento email",
       "composer": "Editor",
       "privacy": "Privacy e sicurezza",
@@ -876,7 +876,11 @@
       },
       "unified_mailbox": {
         "label": "Casella di posta unificata",
-        "description": "Mostra le cartelle combinate (Posta in arrivo, Inviati, ecc.) di tutti gli account collegati"
+        "description": "Mostra le cartelle combinate (Posta in arrivo, Inviati, ecc.) di tutti gli account collegati",
+        "include_group": {
+          "label": "Includi le caselle di gruppo",
+          "description": "Includi anche le caselle condivise o di gruppo nella vista unificata."
+        }
       },
       "colorful_sidebar_icons": {
         "label": "Icone colorate nella barra laterale",
@@ -960,8 +964,8 @@
       }
     },
     "language_region": {
-      "title": "Lingua e regione",
-      "description": "Configura le preferenze di lingua e regionali",
+      "title": "Lingua, regione e ora",
+      "description": "Lingua, formato data, formato ora e altre preferenze regionali",
       "language": {
         "label": "Lingua",
         "description": "Scegli la tua lingua preferita",
@@ -970,10 +974,13 @@
       },
       "date_format": {
         "label": "Formato data",
-        "description": "Come devono essere visualizzate le date",
-        "regional": "Regionale",
-        "iso": "ISO 8601",
-        "custom": "Personalizzato"
+        "description": "Come vengono visualizzate le date nell'elenco delle e-mail",
+        "smart": "Intelligente (in base alla regione)",
+        "relative": "Relativo (1 h fa, 2 g fa)",
+        "full": "Sempre data completa",
+        "preview_today": "Oggi:",
+        "preview_this_week": "Questa settimana:",
+        "preview_older": "Più vecchio:"
       },
       "time_format": {
         "label": "Formato ora",
diff --git a/locales/ja/common.json b/locales/ja/common.json
index 340ba1d9..6aa07403 100644
--- a/locales/ja/common.json
+++ b/locales/ja/common.json
@@ -784,7 +784,7 @@
     "keep_editing": "編集を続ける",
     "tabs": {
       "appearance": "外観",
-      "language": "言語と地域",
+      "language": "言語、地域、時刻",
       "email": "メール動作",
       "composer": "作成",
       "privacy": "プライバシーとセキュリティ",
@@ -876,7 +876,11 @@
       },
       "unified_mailbox": {
         "label": "統合メールボックス",
-        "description": "接続されたすべてのアカウントの統合フォルダ（受信トレイ、送信済みなど）を表示"
+        "description": "接続されたすべてのアカウントの統合フォルダ（受信トレイ、送信済みなど）を表示",
+        "include_group": {
+          "label": "グループ受信トレイを含める",
+          "description": "共有/グループ受信トレイも統合ビューに含めます。"
+        }
       },
       "colorful_sidebar_icons": {
         "label": "カラフルなサイドバーアイコン",
@@ -960,8 +964,8 @@
       }
     },
     "language_region": {
-      "title": "言語と地域",
-      "description": "言語と地域の設定を構成",
+      "title": "言語、地域、時刻",
+      "description": "言語、日付形式、時刻形式、その他の地域設定",
       "language": {
         "label": "言語",
         "description": "お好みの言語を選択",
@@ -970,10 +974,13 @@
       },
       "date_format": {
         "label": "日付形式",
-        "description": "日付の表示形式",
-        "regional": "地域設定",
-        "iso": "ISO 8601",
-        "custom": "カスタム"
+        "description": "メール一覧での日付の表示方法",
+        "smart": "スマート（地域に合わせる）",
+        "relative": "相対表示（1時間前、2日前）",
+        "full": "常に完全な日付",
+        "preview_today": "今日:",
+        "preview_this_week": "今週:",
+        "preview_older": "それ以前:"
       },
       "time_format": {
         "label": "時刻形式",
diff --git a/locales/ko/common.json b/locales/ko/common.json
index c7f808f9..5a45aa98 100644
--- a/locales/ko/common.json
+++ b/locales/ko/common.json
@@ -784,7 +784,7 @@
     "keep_editing": "계속 수정하기",
     "tabs": {
       "appearance": "화면 설정",
-      "language": "언어 및 지역",
+      "language": "언어, 지역 및 시간",
       "email": "메일 동작",
       "composer": "메일 쓰기",
       "privacy": "개인정보 및 보안",
@@ -876,7 +876,11 @@
       },
       "unified_mailbox": {
         "label": "통합 메일함",
-        "description": "연결된 모든 계정의 통합 폴더(받은편지함, 보낸편지함 등)를 표시합니다"
+        "description": "연결된 모든 계정의 통합 폴더(받은편지함, 보낸편지함 등)를 표시합니다",
+        "include_group": {
+          "label": "그룹 받은편지함 포함",
+          "description": "공유/그룹 받은편지함도 통합 보기에 포함합니다."
+        }
       },
       "colorful_sidebar_icons": {
         "label": "컬러풀한 사이드바 아이콘",
@@ -960,8 +964,8 @@
       }
     },
     "language_region": {
-      "title": "언어 및 지역",
-      "description": "언어와 지역 형식을 설정해 주세요",
+      "title": "언어, 지역 및 시간",
+      "description": "언어, 날짜 형식, 시간 형식 및 기타 지역 환경설정",
       "language": {
         "label": "언어",
         "description": "사용할 언어를 선택해 주세요",
@@ -970,10 +974,13 @@
       },
       "date_format": {
         "label": "날짜 형식",
-        "description": "날짜가 표시되는 방식을 설정해요",
-        "regional": "지역 설정",
-        "iso": "ISO 8601",
-        "custom": "사용자 지정"
+        "description": "이메일 목록에 날짜가 표시되는 방식",
+        "smart": "스마트 (지역에 맞춤)",
+        "relative": "상대 시간 (1시간 전, 2일 전)",
+        "full": "항상 전체 날짜",
+        "preview_today": "오늘:",
+        "preview_this_week": "이번 주:",
+        "preview_older": "이전:"
       },
       "time_format": {
         "label": "시간 형식",
diff --git a/locales/lv/common.json b/locales/lv/common.json
index 2c8b16bd..ddc7e420 100644
--- a/locales/lv/common.json
+++ b/locales/lv/common.json
@@ -784,7 +784,7 @@
     "keep_editing": "Turpināt rediģēšanu",
     "tabs": {
       "appearance": "Izskats",
-      "language": "Valoda un reģions",
+      "language": "Valoda, reģions un laiks",
       "email": "Pasta darbība",
       "composer": "Redaktors",
       "privacy": "Privātums un drošība",
@@ -876,7 +876,11 @@
       },
       "unified_mailbox": {
         "label": "Apvienotā pastkaste",
-        "description": "Rādīt apvienotās mapes (Iesūtne, Nosūtītie u.c.) no visiem pievienotajiem kontiem"
+        "description": "Rādīt apvienotās mapes (Iesūtne, Nosūtītie u.c.) no visiem pievienotajiem kontiem",
+        "include_group": {
+          "label": "Iekļaut grupas pastkastes",
+          "description": "Iekļaut apvienotajā skatā arī koplietotās/grupas pastkastes."
+        }
       },
       "colorful_sidebar_icons": {
         "label": "Krāsainas sānjoslas ikonas",
@@ -960,8 +964,8 @@
       }
     },
     "language_region": {
-      "title": "Valoda un reģions",
-      "description": "Iestatiet valodas un reģionālās preferences",
+      "title": "Valoda, reģions un laiks",
+      "description": "Valoda, datuma formāts, laika formāts un citas reģionālās preferences",
       "language": {
         "label": "Valoda",
         "description": "Izvēlieties vēlamo valodu",
@@ -970,10 +974,13 @@
       },
       "date_format": {
         "label": "Datuma formāts",
-        "description": "Kā attēlot datumus",
-        "regional": "Reģionālais",
-        "iso": "ISO 8601",
-        "custom": "Pielāgots"
+        "description": "Kā datumi tiek attēloti e-pasta sarakstā",
+        "smart": "Gudrs (atbilstoši reģionam)",
+        "relative": "Relatīvs (pirms 1 st., pirms 2 d.)",
+        "full": "Vienmēr pilns datums",
+        "preview_today": "Šodien:",
+        "preview_this_week": "Šajā nedēļā:",
+        "preview_older": "Vecāks:"
       },
       "time_format": {
         "label": "Laika formāts",
diff --git a/locales/nl/common.json b/locales/nl/common.json
index f83cb15b..351b56d7 100644
--- a/locales/nl/common.json
+++ b/locales/nl/common.json
@@ -784,7 +784,7 @@
     "keep_editing": "Doorgaan met bewerken",
     "tabs": {
       "appearance": "Uiterlijk",
-      "language": "Taal & Regio",
+      "language": "Taal, Regio & Tijd",
       "email": "E-mailgedrag",
       "composer": "Opstellen",
       "privacy": "Privacy & Beveiliging",
@@ -876,7 +876,11 @@
       },
       "unified_mailbox": {
         "label": "Gecombineerd postvak",
-        "description": "Gecombineerde mappen (Postvak IN, Verzonden, enz.) van alle verbonden accounts weergeven"
+        "description": "Gecombineerde mappen (Postvak IN, Verzonden, enz.) van alle verbonden accounts weergeven",
+        "include_group": {
+          "label": "Groepspostvakken meenemen",
+          "description": "Gedeelde/groepspostvakken ook in de gecombineerde weergave opnemen."
+        }
       },
       "colorful_sidebar_icons": {
         "label": "Gekleurde zijbalkpictogrammen",
@@ -960,8 +964,8 @@
       }
     },
     "language_region": {
-      "title": "Taal & Regio",
-      "description": "Configureer taal- en regiovoorkeuren",
+      "title": "Taal, Regio & Tijd",
+      "description": "Taal, datumnotatie, tijdnotatie en andere regionale voorkeuren",
       "language": {
         "label": "Taal",
         "description": "Kies je voorkeurstaal",
@@ -970,10 +974,13 @@
       },
       "date_format": {
         "label": "Datumnotatie",
-        "description": "Hoe datums moeten worden weergegeven",
-        "regional": "Regionaal",
-        "iso": "ISO 8601",
-        "custom": "Aangepast"
+        "description": "Hoe datums worden weergegeven in de e-maillijst",
+        "smart": "Slim (regionaal)",
+        "relative": "Relatief (1 u geleden, 2 d geleden)",
+        "full": "Altijd volledige datum",
+        "preview_today": "Vandaag:",
+        "preview_this_week": "Deze week:",
+        "preview_older": "Ouder:"
       },
       "time_format": {
         "label": "Tijdnotatie",
diff --git a/locales/pl/common.json b/locales/pl/common.json
index 340bdada..bc336752 100644
--- a/locales/pl/common.json
+++ b/locales/pl/common.json
@@ -784,7 +784,7 @@
     "keep_editing": "Kontynuuj edycję",
     "tabs": {
       "appearance": "Wygląd",
-      "language": "Język i region",
+      "language": "Język, region i czas",
       "email": "Zachowanie poczty e-mail",
       "composer": "Redagowanie",
       "privacy": "Prywatność i bezpieczeństwo",
@@ -876,7 +876,11 @@
       },
       "unified_mailbox": {
         "label": "Wspólna skrzynka",
-        "description": "Wyświetlaj połączone foldery (Odebrane, Wysłane itp.) ze wszystkich połączonych kont"
+        "description": "Wyświetlaj połączone foldery (Odebrane, Wysłane itp.) ze wszystkich połączonych kont",
+        "include_group": {
+          "label": "Uwzględnij skrzynki grupowe",
+          "description": "Dodaj również udostępnione/grupowe skrzynki do widoku wspólnego."
+        }
       },
       "colorful_sidebar_icons": {
         "label": "Kolorowe ikony paska bocznego",
@@ -960,8 +964,8 @@
       }
     },
     "language_region": {
-      "title": "Język i region",
-      "description": "Skonfiguruj preferencje językowe i regionalne",
+      "title": "Język, region i czas",
+      "description": "Język, format daty, format godziny i inne preferencje regionalne",
       "language": {
         "label": "Język",
         "description": "Wybierz preferowany język",
@@ -970,10 +974,13 @@
       },
       "date_format": {
         "label": "Format daty",
-        "description": "Jak mają być wyświetlane daty",
-        "regional": "Regionalny",
-        "iso": "ISO 8601",
-        "custom": "Niestandardowy"
+        "description": "Jak daty są wyświetlane na liście e-maili",
+        "smart": "Inteligentny (regionalny)",
+        "relative": "Względny (1 g temu, 2 d temu)",
+        "full": "Zawsze pełna data",
+        "preview_today": "Dzisiaj:",
+        "preview_this_week": "W tym tygodniu:",
+        "preview_older": "Starsze:"
       },
       "time_format": {
         "label": "Format czasu",
diff --git a/locales/pt/common.json b/locales/pt/common.json
index 3dff895f..9d2f65bf 100644
--- a/locales/pt/common.json
+++ b/locales/pt/common.json
@@ -784,7 +784,7 @@
     "keep_editing": "Continuar editando",
     "tabs": {
       "appearance": "Aparência",
-      "language": "Idioma e Região",
+      "language": "Idioma, Região e Hora",
       "email": "Comportamento de E-mail",
       "composer": "Editor",
       "privacy": "Privacidade e Segurança",
@@ -876,7 +876,11 @@
       },
       "unified_mailbox": {
         "label": "Caixa de correio unificada",
-        "description": "Mostrar pastas combinadas (Entrada, Enviados, etc.) de todas as contas conectadas"
+        "description": "Mostrar pastas combinadas (Entrada, Enviados, etc.) de todas as contas conectadas",
+        "include_group": {
+          "label": "Incluir caixas de grupo",
+          "description": "Incluir também as caixas partilhadas ou de grupo na vista unificada."
+        }
       },
       "colorful_sidebar_icons": {
         "label": "Ícones coloridos na barra lateral",
@@ -960,8 +964,8 @@
       }
     },
     "language_region": {
-      "title": "Idioma e Região",
-      "description": "Configure preferências de idioma e região",
+      "title": "Idioma, Região e Hora",
+      "description": "Idioma, formato de data, formato de hora e outras preferências regionais",
       "language": {
         "label": "Idioma",
         "description": "Escolha seu idioma preferido",
@@ -970,10 +974,13 @@
       },
       "date_format": {
         "label": "Formato de Data",
-        "description": "Como as datas devem ser exibidas",
-        "regional": "Regional",
-        "iso": "ISO 8601",
-        "custom": "Personalizado"
+        "description": "Como as datas são mostradas na lista de e-mails",
+        "smart": "Inteligente (regional)",
+        "relative": "Relativo (há 1 h, há 2 d)",
+        "full": "Sempre data completa",
+        "preview_today": "Hoje:",
+        "preview_this_week": "Esta semana:",
+        "preview_older": "Mais antigo:"
       },
       "time_format": {
         "label": "Formato de Hora",
diff --git a/locales/ru/common.json b/locales/ru/common.json
index 1411ecd2..a2205d4d 100644
--- a/locales/ru/common.json
+++ b/locales/ru/common.json
@@ -784,7 +784,7 @@
     "keep_editing": "Продолжить редактирование",
     "tabs": {
       "appearance": "Внешний вид",
-      "language": "Язык и регион",
+      "language": "Язык, регион и время",
       "email": "Поведение почты",
       "composer": "Редактор",
       "privacy": "Конфиденциальность и безопасность",
@@ -876,7 +876,11 @@
       },
       "unified_mailbox": {
         "label": "Общий почтовый ящик",
-        "description": "Показывать объединённые папки (Входящие, Отправленные и др.) для всех подключённых аккаунтов"
+        "description": "Показывать объединённые папки (Входящие, Отправленные и др.) для всех подключённых аккаунтов",
+        "include_group": {
+          "label": "Включать групповые ящики",
+          "description": "Также объединять общие/групповые ящики в едином представлении."
+        }
       },
       "colorful_sidebar_icons": {
         "label": "Цветные значки боковой панели",
@@ -960,8 +964,8 @@
       }
     },
     "language_region": {
-      "title": "Язык и регион",
-      "description": "Настройте языковые и региональные предпочтения",
+      "title": "Язык, регион и время",
+      "description": "Язык, формат даты, формат времени и другие региональные настройки",
       "language": {
         "label": "Язык",
         "description": "Выберите предпочтительный язык",
@@ -970,10 +974,13 @@
       },
       "date_format": {
         "label": "Формат даты",
-        "description": "Как отображать даты",
-        "regional": "Региональный",
-        "iso": "ISO 8601",
-        "custom": "Пользовательский"
+        "description": "Как отображаются даты в списке писем",
+        "smart": "Умный (по региону)",
+        "relative": "Относительный (1 ч назад, 2 д назад)",
+        "full": "Всегда полная дата",
+        "preview_today": "Сегодня:",
+        "preview_this_week": "На этой неделе:",
+        "preview_older": "Старее:"
       },
       "time_format": {
         "label": "Формат времени",
diff --git a/locales/tr/common.json b/locales/tr/common.json
index b5353c79..53b49aeb 100644
--- a/locales/tr/common.json
+++ b/locales/tr/common.json
@@ -784,7 +784,7 @@
     "keep_editing": "Düzenlemeye devam et",
     "tabs": {
       "appearance": "Görünüm",
-      "language": "Dil ve Bölge",
+      "language": "Dil, Bölge ve Saat",
       "email": "E-posta Davranışı",
       "composer": "Yazıcı",
       "privacy": "Gizlilik ve Güvenlik",
@@ -876,7 +876,11 @@
       },
       "unified_mailbox": {
         "label": "Birleşik Posta Kutusu",
-        "description": "Bağlı tüm hesaplardaki birleşik klasörleri (Gelen Kutusu, Gönderilenler vb.) göster"
+        "description": "Bağlı tüm hesaplardaki birleşik klasörleri (Gelen Kutusu, Gönderilenler vb.) göster",
+        "include_group": {
+          "label": "Grup gelen kutularını dahil et",
+          "description": "Paylaşılan/grup gelen kutularını da birleşik görünüme dahil et."
+        }
       },
       "colorful_sidebar_icons": {
         "label": "Renkli Kenar Çubuğu Simgeleri",
@@ -960,8 +964,8 @@
       }
     },
     "language_region": {
-      "title": "Dil ve Bölge",
-      "description": "Dil ve bölgesel tercihleri yapılandırın",
+      "title": "Dil, Bölge ve Saat",
+      "description": "Dil, tarih biçimi, saat biçimi ve diğer bölgesel tercihler",
       "language": {
         "label": "Dil",
         "description": "Tercih ettiğiniz dili seçin",
@@ -970,10 +974,13 @@
       },
       "date_format": {
         "label": "Tarih Biçimi",
-        "description": "Tarihlerin nasıl görüntüleneceği",
-        "regional": "Bölgesel",
-        "iso": "ISO 8601",
-        "custom": "Özel"
+        "description": "Tarihlerin e-posta listesinde nasıl gösterileceği",
+        "smart": "Akıllı (bölgeye duyarlı)",
+        "relative": "Göreceli (1 sa önce, 2 g önce)",
+        "full": "Her zaman tam tarih",
+        "preview_today": "Bugün:",
+        "preview_this_week": "Bu hafta:",
+        "preview_older": "Daha eski:"
       },
       "time_format": {
         "label": "Saat Biçimi",
diff --git a/locales/uk/common.json b/locales/uk/common.json
index a1863b4e..5ee0ba1a 100644
--- a/locales/uk/common.json
+++ b/locales/uk/common.json
@@ -784,7 +784,7 @@
     "keep_editing": "Продовжуйте редагувати",
     "tabs": {
       "appearance": "Зовнішній вигляд",
-      "language": "Мова та регіон",
+      "language": "Мова, регіон і час",
       "email": "Поведінка електронної пошти",
       "composer": "Композитор",
       "privacy": "Конфіденційність і безпека",
@@ -876,7 +876,11 @@
       },
       "unified_mailbox": {
         "label": "Спільна поштова скринька",
-        "description": "Показувати об'єднані папки (Вхідні, Надіслані тощо) для всіх підключених облікових записів"
+        "description": "Показувати об'єднані папки (Вхідні, Надіслані тощо) для всіх підключених облікових записів",
+        "include_group": {
+          "label": "Включати групові скриньки",
+          "description": "Також об'єднувати спільні/групові скриньки у спільному перегляді."
+        }
       },
       "colorful_sidebar_icons": {
         "label": "Кольорові значки бічної панелі",
@@ -960,8 +964,8 @@
       }
     },
     "language_region": {
-      "title": "Мова та регіон",
-      "description": "Налаштуйте мовні та регіональні параметри",
+      "title": "Мова, регіон і час",
+      "description": "Мова, формат дати, формат часу та інші регіональні налаштування",
       "language": {
         "label": "Мова",
         "description": "Виберіть бажану мову",
@@ -970,10 +974,13 @@
       },
       "date_format": {
         "label": "Формат дати",
-        "description": "Як мають відображатися дати",
-        "regional": "Регіональний",
-        "iso": "ISO 8601",
-        "custom": "Довільний"
+        "description": "Як відображаються дати у списку листів",
+        "smart": "Розумний (за регіоном)",
+        "relative": "Відносний (1 год тому, 2 дн тому)",
+        "full": "Завжди повна дата",
+        "preview_today": "Сьогодні:",
+        "preview_this_week": "Цього тижня:",
+        "preview_older": "Старіше:"
       },
       "time_format": {
         "label": "Формат часу",
diff --git a/locales/zh/common.json b/locales/zh/common.json
index 3344df95..804bb0aa 100644
--- a/locales/zh/common.json
+++ b/locales/zh/common.json
@@ -784,7 +784,7 @@
     "keep_editing": "继续编辑",
     "tabs": {
       "appearance": "外观",
-      "language": "语言及地区",
+      "language": "语言、地区与时间",
       "email": "邮件行为",
       "composer": "邮件撰写",
       "privacy": "隐私与安全",
@@ -876,7 +876,11 @@
       },
       "unified_mailbox": {
         "label": "统一邮箱",
-        "description": "显示所有已连接账户的合并文件夹（收件箱、已发送等）"
+        "description": "显示所有已连接账户的合并文件夹（收件箱、已发送等）",
+        "include_group": {
+          "label": "包含群组收件箱",
+          "description": "在统一视图中也合并共享/群组收件箱。"
+        }
       },
       "colorful_sidebar_icons": {
         "label": "彩色侧边栏图标",
@@ -960,8 +964,8 @@
       }
     },
     "language_region": {
-      "title": "语言及地区",
-      "description": "配置语言和区域首选项",
+      "title": "语言、地区与时间",
+      "description": "语言、日期格式、时间格式以及其他区域设置",
       "language": {
         "label": "语言",
         "description": "选择您的首选语言",
@@ -970,10 +974,13 @@
       },
       "date_format": {
         "label": "日期格式",
-        "description": "日期应如何显示",
-        "regional": "区域格式",
-        "iso": "ISO 8601",
-        "custom": "自定义"
+        "description": "电子邮件列表中日期的显示方式",
+        "smart": "智能（按地区）",
+        "relative": "相对时间（1 小时前、2 天前）",
+        "full": "始终完整日期",
+        "preview_today": "今天：",
+        "preview_this_week": "本周：",
+        "preview_older": "更早："
       },
       "time_format": {
         "label": "时间格式",
diff --git a/proxy.ts b/proxy.ts
index 814abbd5..26fc1dcb 100644
--- a/proxy.ts
+++ b/proxy.ts
@@ -97,8 +97,8 @@ export async function proxy(request: NextRequest) {
   const pluginFrameOrigins = await getEnabledPluginFrameOrigins();
   const frameSrc =
     pluginFrameOrigins.length > 0
-      ? `frame-src 'self' ${pluginFrameOrigins.join(" ")}`
-      : `frame-src 'self'`;
+      ? `frame-src 'self' blob: ${pluginFrameOrigins.join(" ")}`
+      : `frame-src 'self' blob:`;
 
   const csp = [
     `default-src 'self'`,
@@ -108,7 +108,7 @@ export async function proxy(request: NextRequest) {
     `font-src 'self'`,
     `connect-src ${connectSrc}`,
     frameSrc,
-    `object-src 'none'`,
+    `object-src 'self' blob:`,
     `base-uri 'self'`,
     `form-action 'self'`,
     `frame-ancestors ${frameAncestors}`,
diff --git a/stores/email-store.ts b/stores/email-store.ts
index 4bf38165..c0a28280 100644
--- a/stores/email-store.ts
+++ b/stores/email-store.ts
@@ -147,11 +147,16 @@ interface EmailStore {
    * pass the active account's id explicitly (no `__default__` sentinel).
    * `destMailboxId` is the raw JMAP id on the destination server (not the
    * `accountId:mailboxId` namespace used for shared folders).
+   * `destJmapAccountId` overrides the destination client's primary account
+   * for the import — used when dropping into a delegated/shared mailbox that
+   * is owned by a different JMAP account but accessed through the same
+   * client (i.e. there is no separate connected client for the owner).
    */
   crossAccountMoveEmails: (
     emailIdsBySource: Map<string, string[]>,
     destAccountId: string,
     destMailboxId: string,
+    destJmapAccountId?: string,
   ) => Promise<void>;
   searchEmails: (client: IJMAPClient, query: string) => Promise<void>;
   advancedSearch: (client: IJMAPClient) => Promise<void>;
@@ -308,8 +313,16 @@ function resolveActionMailboxes(): Mailbox[] {
  * fresh mailbox list so the helpers can resolve the role mailbox per account.
  * Accounts whose mailbox fetch fails are skipped - the unified result will
  * surface that in its per-account error map.
+ *
+ * When `includeGroup` is true, also emits one synthetic entry per shared
+ * owner account reachable through each logged-in client. The shared entries
+ * are flagged with `isShared: true` so `lib/unified-mailbox.ts` routes JMAP
+ * requests via `originalId` + owner accountId.
  */
-async function buildUnifiedAccountClients(): Promise<UnifiedAccountClient[]> {
+export async function buildUnifiedAccountClients(
+  opts: { includeGroup?: boolean } = {},
+): Promise<UnifiedAccountClient[]> {
+  const { includeGroup = false } = opts;
   const authAccounts = useAccountStore.getState().accounts.filter((a) => a.isConnected);
   const allClients = useAuthStore.getState().getAllConnectedClients();
   const built: UnifiedAccountClient[] = [];
@@ -317,8 +330,31 @@ async function buildUnifiedAccountClients(): Promise<UnifiedAccountClient[]> {
     const c = allClients.get(a.id);
     if (!c) continue;
     try {
-      const mailboxes = await c.getMailboxes();
-      built.push({ accountId: a.id, accountLabel: a.label || a.email, client: c, mailboxes });
+      const mailboxes = includeGroup ? await c.getAllMailboxes() : await c.getMailboxes();
+      const ownMailboxes = includeGroup
+        ? mailboxes.filter((m) => !m.isShared)
+        : mailboxes;
+      built.push({ accountId: a.id, accountLabel: a.label || a.email, client: c, mailboxes: ownMailboxes, isShared: false });
+
+      if (includeGroup) {
+        const sharedByOwner = new Map<string, Mailbox[]>();
+        for (const m of mailboxes) {
+          if (!m.isShared || !m.accountId || m.accountId === a.id) continue;
+          const list = sharedByOwner.get(m.accountId) ?? [];
+          list.push(m);
+          sharedByOwner.set(m.accountId, list);
+        }
+        for (const [ownerId, ownerMailboxes] of sharedByOwner) {
+          const label = ownerMailboxes.find((m) => m.accountName)?.accountName || ownerId;
+          built.push({
+            accountId: ownerId,
+            accountLabel: label,
+            client: c,
+            mailboxes: ownerMailboxes,
+            isShared: true,
+          });
+        }
+      }
     } catch {
       /* skip account on mailbox fetch failure */
     }
@@ -662,8 +698,9 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       set({ isLoadingMore: true, error: null });
       try {
         const emailsPerPage = useSettingsStore.getState().emailsPerPage;
+        const includeGroup = useSettingsStore.getState().includeGroupInUnified;
         const position = emails.length;
-        const built = await buildUnifiedAccountClients();
+        const built = await buildUnifiedAccountClients({ includeGroup });
         const { searchFilters } = get();
         const hasFilters = !isFilterEmpty(searchFilters);
         const result = hasFilters
@@ -1194,7 +1231,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
     }
   },
 
-  crossAccountMoveEmails: async (emailIdsBySource, destAccountId, destMailboxId) => {
+  crossAccountMoveEmails: async (emailIdsBySource, destAccountId, destMailboxId, destJmapAccountId) => {
     if (emailIdsBySource.size === 0) return;
     set({ isLoading: true, error: null });
     try {
@@ -1227,7 +1264,7 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
             }
             const blob = await sourceClient.fetchBlob(full.blobId);
             const keywords: Record<string, boolean> = { ...(full.keywords ?? {}) };
-            await destClient.importRawEmail(blob, { [destMailboxId]: true }, keywords);
+            await destClient.importRawEmail(blob, { [destMailboxId]: true }, keywords, destJmapAccountId);
             await sourceClient.deleteEmail(emailId);
             return emailId;
           }),
@@ -1360,7 +1397,8 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       const emailsPerPage = useSettingsStore.getState().emailsPerPage;
 
       if (isUnifiedView && unifiedRole) {
-        const built = await buildUnifiedAccountClients();
+        const includeGroup = useSettingsStore.getState().includeGroupInUnified;
+        const built = await buildUnifiedAccountClients({ includeGroup });
         const result = await searchUnifiedEmails(built, unifiedRole, query, emailsPerPage, 0);
         const externals = await emailHooks.onProvideSearchResults.transform([] as ExternalSearchResult[], { query, filters: get().searchFilters });
         set({
@@ -1426,7 +1464,8 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       const emailsPerPage = useSettingsStore.getState().emailsPerPage;
 
       if (isUnifiedView && unifiedRole) {
-        const built = await buildUnifiedAccountClients();
+        const includeGroup = useSettingsStore.getState().includeGroupInUnified;
+        const built = await buildUnifiedAccountClients({ includeGroup });
         const result = await advancedSearchUnifiedEmails(
           built,
           unifiedRole,
diff --git a/stores/pro-tab-store.ts b/stores/pro-tab-store.ts
index 8db0ef96..0178f370 100644
--- a/stores/pro-tab-store.ts
+++ b/stores/pro-tab-store.ts
@@ -353,6 +353,14 @@ export const useProTabStore = create<ProTabState>()(
         const target = state.tabs.find((t) => t.id === targetTabId);
         if (!dragged || !target) return;
 
+        // Mirror the moveTabToPane guard: never let a cross-pane reorder
+        // empty the main pane, which would otherwise leave the layout with
+        // a blank main pane next to a populated split pane.
+        if (dragged.paneId === 'main' && target.paneId !== 'main') {
+          const otherMainTabs = state.tabs.filter((t) => t.paneId === 'main' && t.id !== draggedId);
+          if (otherMainTabs.length === 0) return;
+        }
+
         const next = state.tabs.filter((t) => t.id !== draggedId);
         const insertAt = next.findIndex((t) => t.id === targetTabId) + (edge === 'after' ? 1 : 0);
         const reassigned: ProTab = dragged.paneId === target.paneId
@@ -504,6 +512,15 @@ export const useProTabStore = create<ProTabState>()(
           state.loadedTabIds = [HOME_TAB.id];
           return;
         }
+        // Heal broken state where every tab ended up on the split pane:
+        // collapse the split so the surviving tabs return to main, otherwise
+        // the layout would render an empty main pane next to the split.
+        if (!state.tabs.some((t) => t.paneId === 'main')) {
+          state.tabs = state.tabs.map((t) => ({ ...t, paneId: 'main' as const }));
+          state.activeSplitTabId = null;
+          state.splitOrientation = null;
+          state.focusedPaneId = 'main';
+        }
         if (!state.tabs.some((t) => t.id === state.activeTabId && t.paneId === 'main')) {
           state.activeTabId = state.tabs.find((t) => t.paneId === 'main')?.id ?? HOME_TAB.id;
         }
diff --git a/stores/settings-store.ts b/stores/settings-store.ts
index 5a419dc3..bfc5010a 100644
--- a/stores/settings-store.ts
+++ b/stores/settings-store.ts
@@ -31,7 +31,7 @@ export type ListDensity = Density;
 export type DeleteAction = 'trash' | 'trash-and-read' | 'permanent';
 export type ReplyMode = 'reply' | 'replyAll';
 export type SignaturePosition = 'above_quote' | 'below_quote';
-export type DateFormat = 'regional' | 'iso' | 'custom';
+export type DateFormat = 'smart' | 'relative' | 'full';
 export type TimeFormat = '12h' | '24h';
 export type FirstDayOfWeek = 0 | 1; // 0 = Sunday, 1 = Monday
 export type ExternalContentPolicy = 'ask' | 'block' | 'allow';
@@ -204,6 +204,7 @@ interface SettingsState {
 
   // Unified Mailbox
   enableUnifiedMailbox: boolean;
+  includeGroupInUnified: boolean;
 
   // Email Display
   disableThreading: boolean; // Show emails as individual messages instead of grouped by conversation
@@ -301,7 +302,7 @@ const DEFAULT_SETTINGS = {
   animationsEnabled: true,
 
   // Language & Region
-  dateFormat: 'regional' as DateFormat,
+  dateFormat: 'smart' as DateFormat,
   timeFormat: '24h' as TimeFormat,
   firstDayOfWeek: 1 as FirstDayOfWeek, // Monday
 
@@ -378,6 +379,7 @@ const DEFAULT_SETTINGS = {
 
   // Unified Mailbox
   enableUnifiedMailbox: false,
+  includeGroupInUnified: false,
 
   // Email Display
   disableThreading: false,
@@ -547,6 +549,7 @@ export const useSettingsStore = create<SettingsState>()(
           // proInterface is intentionally omitted - it's a per-device choice
           // (see DEVICE_LOCAL_SETTING_KEYS) and must not be synced.
           enableUnifiedMailbox: state.enableUnifiedMailbox,
+          includeGroupInUnified: state.includeGroupInUnified,
           senderFavicons: state.senderFavicons,
           showAvatarsInJunk: state.showAvatarsInJunk,
           colorfulSidebarIcons: state.colorfulSidebarIcons,
@@ -765,7 +768,7 @@ export const useSettingsStore = create<SettingsState>()(
     }),
     {
       name: 'settings-storage',
-      version: 3,
+      version: 4,
       migrate: (persisted, version) => {
         const state = persisted as Record<string, unknown>;
         if (version < 2 && state.listDensity) {
@@ -779,6 +782,12 @@ export const useSettingsStore = create<SettingsState>()(
           state.protocolOpenMode = state.protocolMailtoOpenMode;
         }
         delete state.protocolMailtoOpenMode;
+        // v4: `dateFormat` was repurposed from 'regional'|'iso'|'custom' to
+        // 'smart'|'relative'|'full'. The old setting was never read anywhere,
+        // so every persisted value maps to the new default.
+        if (version < 4) {
+          state.dateFormat = 'smart';
+        }
         return state as unknown as SettingsState;
       },
       onRehydrateStorage: () => {