diff --git a/webui/src/App.tsx b/webui/src/App.tsx
index ca416aa..cfd19f9 100644
--- a/webui/src/App.tsx
+++ b/webui/src/App.tsx
@@ -2,7 +2,7 @@ import { Navigate, Route, Routes } from "react-router-dom";
 import { lazy, Suspense, useEffect, useMemo, useState } from "react";
 import { fetchSession, fetchShellAuth, updateProfile } from "./api/auth";
 import { fetchPlatformModules, fetchPlatformStatus } from "./api/platform";
-import { AUTH_REQUIRED_EVENT, loadApiSettings, saveApiSettings, type AuthRequiredEventDetail } from "./api/client";
+import { AUTH_REQUIRED_EVENT, isApiError, loadApiSettings, saveApiSettings, type AuthRequiredEventDetail } from "./api/client";
 import type { ApiSettings, AuthInfo, AuthSessionInfo, AuthUpdate, AuthUser, LoginResponse, PlatformModuleInfo, PlatformWebModule, UserUiPreferences } from "./types";
 import AppShell from "./layout/AppShell";
 import PublicLandingPage from "./features/auth/PublicLandingPage";
@@ -32,6 +32,7 @@ export default function App() {
   const [platformModules, setPlatformModules] = useState<PlatformModuleInfo[] | null>(null);
   const [remoteWebModules, setRemoteWebModules] = useState<PlatformWebModule[]>([]);
   const [maintenanceMode, setMaintenanceMode] = useState<{enabled: boolean;message?: string | null;}>({ enabled: false, message: null });
+  const [backendReachable, setBackendReachable] = useState(true);
   const [systemLanguages, setSystemLanguages] = useState<{available: PlatformLanguage[];enabled: string[];defaultLanguage: string;} | null>(null);
   const [reloginMessage, setReloginMessage] = useState("");
 
@@ -87,6 +88,7 @@ export default function App() {
       try {
         const response = await fetchPlatformStatus(settings);
         if (cancelled) return;
+        setBackendReachable(true);
         setMaintenanceMode(response.maintenance_mode);
         if (response.i18n) {
           setSystemLanguages({
@@ -100,7 +102,10 @@ export default function App() {
           });
         }
       } catch {
-        if (!cancelled) setMaintenanceMode({ enabled: false, message: null });
+        if (!cancelled) {
+          setBackendReachable(false);
+          setMaintenanceMode({ enabled: false, message: null });
+        }
       }
     }
 
@@ -121,9 +126,13 @@ export default function App() {
     async function bootstrapAuth() {
       try {
         const shellAuth = await fetchShellAuth(settings);
-        if (!cancelled) setAuth(normalizeAuthInfo(shellAuth));
-      } catch {
         if (!cancelled) {
+          setBackendReachable(true);
+          setAuth(normalizeAuthInfo(shellAuth));
+        }
+      } catch (error) {
+        if (!cancelled) {
+          setBackendReachable(isApiError(error));
           const cleared = { ...settings, accessToken: "" };
           setSettings(cleared);
           saveApiSettings(cleared);
@@ -243,6 +252,7 @@ export default function App() {
       try {
         const sessionInfo = await fetchSession(settings);
         if (cancelled) return;
+        setBackendReachable(true);
         const shellRefreshDue = now - lastShellRefreshAt >= 60_000;
         if (!sessionMatchesAuth(sessionInfo, currentAuth) || shellRefreshDue) {
           const shellAuth = await fetchShellAuth(settings);
@@ -252,7 +262,10 @@ export default function App() {
             ? normalizeAuthInfo(mergeAuthPayload(current, shellAuth))
             : normalizeAuthInfo(shellAuth));
         }
-      } catch {
+      } catch (error) {
+        if (!cancelled && !isApiError(error)) {
+          setBackendReachable(false);
+        }
 
 
         // A background refresh must not log the user out on a transient network error.
@@ -273,7 +286,7 @@ export default function App() {
       <PlatformLanguageProvider systemAvailableLanguages={systemLanguages?.available} systemEnabledLanguageCodes={systemLanguages?.enabled} defaultLanguage={systemLanguages?.defaultLanguage} moduleTranslations={moduleTranslations}>
       <PlatformModulesProvider modules={webModules}>
         <UnsavedChangesProvider>
-        <AppShell settings={settings} auth={null} onSettingsChange={updateSettings} onAuthChange={updateAuth} publicMode navItems={navItems} maintenanceMode={maintenanceMode}>
+        <AppShell settings={settings} auth={null} onSettingsChange={updateSettings} onAuthChange={updateAuth} publicMode navItems={navItems} maintenanceMode={maintenanceMode} backendReachable={backendReachable}>
         <div className="public-landing">
           <section className="public-card">
             <div className="public-kicker">i18n:govoplan-core.govoplan.a84c0a85</div>
@@ -293,7 +306,7 @@ export default function App() {
       <PlatformLanguageProvider systemAvailableLanguages={systemLanguages?.available} systemEnabledLanguageCodes={systemLanguages?.enabled} defaultLanguage={systemLanguages?.defaultLanguage} moduleTranslations={moduleTranslations}>
       <PlatformModulesProvider modules={webModules}>
         <UnsavedChangesProvider>
-        <AppShell settings={settings} auth={null} onSettingsChange={updateSettings} onAuthChange={updateAuth} publicMode navItems={navItems} maintenanceMode={maintenanceMode}>
+        <AppShell settings={settings} auth={null} onSettingsChange={updateSettings} onAuthChange={updateAuth} publicMode navItems={navItems} maintenanceMode={maintenanceMode} backendReachable={backendReachable}>
           <PublicLandingPage settings={settings} maintenanceMode={maintenanceMode} onLogin={handlePublicLogin} />
         </AppShell>
       </UnsavedChangesProvider>
@@ -324,7 +337,7 @@ export default function App() {
       moduleTranslations={moduleTranslations}>
     <PlatformModulesProvider modules={webModules}>
       <UnsavedChangesProvider>
-      <AppShell settings={settings} auth={auth} onSettingsChange={updateSettings} onAuthChange={updateAuth} navItems={navItems} maintenanceMode={maintenanceMode}>
+      <AppShell settings={settings} auth={auth} onSettingsChange={updateSettings} onAuthChange={updateAuth} navItems={navItems} maintenanceMode={maintenanceMode} backendReachable={backendReachable}>
       <Suspense fallback={<div className="content-pad"><p className="muted">i18n:govoplan-core.loading_module.50161f3c</p></div>}>
         <Routes key={(auth.active_tenant ?? auth.tenant).id}>
           <Route path="/" element={<Navigate to={defaultRoute} replace />} />
diff --git a/webui/src/components/MessageDisplayPanel.tsx b/webui/src/components/MessageDisplayPanel.tsx
index b255e9a..abc1680 100644
--- a/webui/src/components/MessageDisplayPanel.tsx
+++ b/webui/src/components/MessageDisplayPanel.tsx
@@ -1,5 +1,5 @@
 import { useEffect, useMemo, useState, type ReactNode } from "react";
-import { Archive, LockKeyhole, Paperclip } from "lucide-react";
+import { Archive, Link2, LockKeyhole, Paperclip, X } from "lucide-react";
 import { i18nMessage, usePlatformLanguage } from "../i18n/LanguageContext";
 import SegmentedControl from "./SegmentedControl";
 
@@ -14,6 +14,7 @@ export type MessageDisplayAttachment = {
   contentType?: string | null;
   sizeBytes?: number | null;
   detail?: string | null;
+  linkedToCampaign?: boolean | null;
   archiveGroup?: string | null;
   archiveLabel?: string | null;
   protected?: boolean | null;
@@ -159,9 +160,15 @@ function AttachmentRow({ attachment, index }: {attachment: MessageDisplayAttachm
   const contentType = formatContentType(attachment.contentType);
   const size = formatBytes(attachment.sizeBytes);
   const hasMeta = Boolean(contentType || size);
+  const LinkIcon = attachment.linkedToCampaign === true ? Link2 : attachment.linkedToCampaign === false ? X : Paperclip;
+  const linkStateClass = attachment.linkedToCampaign === true ?
+  " is-linked" :
+  attachment.linkedToCampaign === false ?
+  " is-unlinked" :
+  "";
   return (
-    <div className="message-display-attachment-row">
-      <Paperclip size={14} aria-hidden="true" />
+    <div className={`message-display-attachment-row${linkStateClass}`}>
+      <LinkIcon size={14} aria-hidden="true" />
       <span>
         <strong>{attachment.filename || i18nMessage("i18n:govoplan-core.attachment_value.01801a54", { value0: index + 1 })}</strong>
         {attachment.detail && <small className="message-display-attachment-detail">{attachment.detail}</small>}
diff --git a/webui/src/components/ToggleSwitch.tsx b/webui/src/components/ToggleSwitch.tsx
index b40982a..5e6ce36 100644
--- a/webui/src/components/ToggleSwitch.tsx
+++ b/webui/src/components/ToggleSwitch.tsx
@@ -5,15 +5,21 @@ import { usePlatformLanguage } from "../i18n/LanguageContext";
 
 type ToggleSwitchProps = {
   label: ReactNode;
+  activeLabel?: ReactNode;
+  inactiveLabel?: ReactNode;
   checked: boolean;
   onChange?: (checked: boolean) => void;
   disabled?: boolean;
   help?: ReactNode;
 };
 
-export default function ToggleSwitch({ label, checked, onChange, disabled = false, help }: ToggleSwitchProps) {
+export default function ToggleSwitch({ label, activeLabel, inactiveLabel, checked, onChange, disabled = false, help }: ToggleSwitchProps) {
   const { translateText } = usePlatformLanguage();
+  const hasStateLabels = activeLabel !== undefined || inactiveLabel !== undefined;
   const renderedLabel = typeof label === "string" ? translateText(label) : label;
+  const renderedInactiveLabel = typeof inactiveLabel === "string" ? translateText(inactiveLabel) : inactiveLabel;
+  const renderedActiveLabel = typeof activeLabel === "string" ? translateText(activeLabel) : activeLabel;
+  const inputLabel = typeof renderedLabel === "string" ? renderedLabel : undefined;
   return (
     <label className={`toggle-switch-row ${disabled ? "disabled" : ""}`}>
       <input
@@ -21,12 +27,25 @@ export default function ToggleSwitch({ label, checked, onChange, disabled = fals
         type="checkbox"
         checked={checked}
         disabled={disabled}
+        aria-label={inputLabel}
         onChange={(event) => onChange?.(event.target.checked)}
       />
+      {hasStateLabels && inactiveLabel !== undefined &&
+      <span className="toggle-switch-state-label is-inactive" data-selected={!checked || undefined}>
+          {renderedInactiveLabel}
+        </span>
+      }
       <span className="toggle-switch-track" aria-hidden="true"><span className="toggle-switch-thumb" /></span>
+      {hasStateLabels && activeLabel !== undefined &&
+      <span className="toggle-switch-state-label is-active" data-selected={checked || undefined}>
+          {renderedActiveLabel}
+        </span>
+      }
+      {!hasStateLabels &&
       <span className="toggle-switch-copy">
         <FieldLabel className="toggle-switch-label" help={help ?? helpForFieldLabel(label)}>{renderedLabel}</FieldLabel>
       </span>
+      }
     </label>
   );
 }
diff --git a/webui/src/components/mail/MailServerSettingsPanel.tsx b/webui/src/components/mail/MailServerSettingsPanel.tsx
index 79f4744..593e244 100644
--- a/webui/src/components/mail/MailServerSettingsPanel.tsx
+++ b/webui/src/components/mail/MailServerSettingsPanel.tsx
@@ -1,10 +1,9 @@
-import { useEffect, useState } from "react";
+import { useEffect, useRef, useState } from "react";
 import Button from "../Button";
 import { CredentialFields } from "../CredentialPanel";
 import DismissibleAlert from "../DismissibleAlert";
 import FormField from "../FormField";
 import SegmentedControl from "../SegmentedControl";
-import ToggleSwitch from "../ToggleSwitch";
 
 export type MailServerSecurity = "plain" | "tls" | "starttls" | string;
 
@@ -48,7 +47,7 @@ export type MailServerFolderLookupResult = {
   details?: Record<string, unknown> | null;
 };
 
-export type MailServerSettingsSection = "smtp" | "imap" | "advanced";
+export type MailServerSettingsSection = "smtp" | "imap";
 export type MailServerSettingsMode = "all" | "server" | "credentials";
 
 export type MailServerSettingsPanelProps = {
@@ -72,30 +71,11 @@ export type MailServerSettingsPanelProps = {
   imapActionDisabled?: boolean;
   smtpTestLabel?: string;
   imapTestLabel?: string;
-  folderLookupLabel?: string;
   busyAction?: "smtp" | "imap" | "folders" | string | null;
   onTestSmtp?: () => void;
   onTestImap?: () => void;
-  onLookupFolders?: () => void;
   smtpTestResult?: MailServerConnectionTestResult | null;
   imapTestResult?: MailServerConnectionTestResult | null;
-  folderLookupResult?: MailServerFolderLookupResult | null;
-  onUseDetectedFolder?: () => void;
-  useDetectedFolderDisabled?: boolean;
-  mockToggle?: {
-    label?: string;
-    checked: boolean;
-    disabled?: boolean;
-    onChange: (checked: boolean) => void;
-  };
-  append?: {
-    enabled: boolean;
-    folder: string;
-    disabled?: boolean;
-    folderDisabled?: boolean;
-    onEnabledChange: (enabled: boolean) => void;
-    onFolderChange: (folder: string) => void;
-  };
   disabled?: boolean;
   className?: string;
   floatingResults?: boolean;
@@ -202,6 +182,19 @@ export function hasMailImapSettings(values: Array<string | number | null | undef
   return values.some((value) => String(value ?? "").trim() !== "");
 }
 
+export function resolveMailServerSettingsActiveSection(
+activeSection: MailServerSettingsSection,
+initialSection: MailServerSettingsSection,
+previousInitialSection: MailServerSettingsSection,
+visibleSectionIds: readonly MailServerSettingsSection[])
+: MailServerSettingsSection {
+  const fallbackSection = visibleSectionIds[0] ?? "smtp";
+  const initialSectionVisible = visibleSectionIds.includes(initialSection);
+  if (previousInitialSection !== initialSection && initialSectionVisible) return initialSection;
+  if (!visibleSectionIds.includes(activeSection)) return initialSectionVisible ? initialSection : fallbackSection;
+  return activeSection;
+}
+
 export default function MailServerSettingsPanel({
   smtp,
   imap,
@@ -223,18 +216,11 @@ export default function MailServerSettingsPanel({
   imapActionDisabled = imapServerDisabled,
   smtpTestLabel = "i18n:govoplan-core.test_smtp.e5697981",
   imapTestLabel = "i18n:govoplan-core.test_imap.ef1bd79c",
-  folderLookupLabel = "i18n:govoplan-core.folders.c603ab65",
   busyAction = null,
   onTestSmtp,
   onTestImap,
-  onLookupFolders,
   smtpTestResult = null,
   imapTestResult = null,
-  folderLookupResult = null,
-  onUseDetectedFolder,
-  useDetectedFolderDisabled = false,
-  mockToggle,
-  append,
   disabled = false,
   className = "",
   floatingResults = false,
@@ -254,35 +240,31 @@ export default function MailServerSettingsPanel({
   const imapSecurity = stringValue(imap.security, "tls");
   const smtpPort = stringValue(smtp.port, String(defaultSmtpPort(smtpSecurity)));
   const imapPort = stringValue(imap.port, String(defaultImapPort(imapSecurity)));
-  const appendTargetFolder = append ? append.folder : stringValue(imap.sent_folder, "auto");
-  const appendTargetDisabled = append ? disabled || append.folderDisabled : imapFieldsDisabled;
-  const canLookupAppendFolders = Boolean(onLookupFolders) && !appendTargetDisabled;
-  const appendTargetHelp = append ?
-  "i18n:govoplan-core.folder_for_sent_message_copies_leave_as_auto_unl.a62586e9" :
-  "i18n:govoplan-core.folder_used_when_this_imap_account_is_used_for_s.08503f5e";
   const allSections: {id: MailServerSettingsSection;label: string;}[] = [
   { id: "smtp", label: "i18n:govoplan-core.smtp.efff9cca" },
-  { id: "imap", label: "i18n:govoplan-core.imap.271f9ef2" },
-  { id: "advanced", label: "i18n:govoplan-core.advanced.4d064726" }];
+  { id: "imap", label: "i18n:govoplan-core.imap.271f9ef2" }];
   const visibleSectionSet = new Set(visibleSections ?? allSections.map((section) => section.id));
   const sections = allSections.filter((section) => visibleSectionSet.has(section.id));
-  const fallbackSection = sections[0]?.id ?? "smtp";
-  const resolvedInitialSection = sections.some((section) => section.id === initialSection) ? initialSection : fallbackSection;
-  const sectionKey = sections.map((section) => section.id).join("|");
+  const visibleSectionIds = sections.map((section) => section.id);
+  const fallbackSection = visibleSectionIds[0] ?? "smtp";
+  const resolvedInitialSection = visibleSectionIds.includes(initialSection) ? initialSection : fallbackSection;
+  const sectionKey = visibleSectionIds.join("|");
   const [activeSection, setActiveSection] = useState<MailServerSettingsSection>(resolvedInitialSection);
+  const previousInitialSectionRef = useRef(initialSection);
   const showSectionSwitcher = sections.length > 1;
   const showServerFields = mode !== "credentials";
   const showCredentialFields = mode !== "server";
 
   useEffect(() => {
-    if (!sections.some((section) => section.id === activeSection)) {
-      setActiveSection(resolvedInitialSection);
-      return;
-    }
-    if (initialSection !== activeSection && sections.some((section) => section.id === initialSection)) {
-      setActiveSection(initialSection);
-    }
-  }, [activeSection, initialSection, resolvedInitialSection, sectionKey]);
+    const nextSection = resolveMailServerSettingsActiveSection(
+      activeSection,
+      initialSection,
+      previousInitialSectionRef.current,
+      visibleSectionIds
+    );
+    previousInitialSectionRef.current = initialSection;
+    if (nextSection !== activeSection) setActiveSection(nextSection);
+  }, [activeSection, initialSection, sectionKey]);
 
 
   function patchSmtpSecurity(security: MailServerSecurity) {
@@ -324,10 +306,10 @@ export default function MailServerSettingsPanel({
             <div className="form-grid compact responsive-form-grid mail-server-form-grid">
               {showServerFields &&
               <>
-              <div className="mail-server-field-heading">i18n:govoplan-core.server.cb0cb170</div>
-              <FormField label="i18n:govoplan-core.host.3960ec4c"><input value={stringValue(smtp.host)} disabled={smtpFieldsDisabled} onChange={(event) => onSmtpChange({ host: event.target.value })} /></FormField>
+              <FormField label="i18n:govoplan-core.server.cb0cb170" help="i18n:govoplan-core.mail_server_hostname_or_ip_address_for_the_selec.596c2d69"><input value={stringValue(smtp.host)} disabled={smtpFieldsDisabled} onChange={(event) => onSmtpChange({ host: event.target.value })} /></FormField>
               <FormField label="i18n:govoplan-core.port.fe035157"><input type="number" min={1} max={65535} value={smtpPort} disabled={smtpFieldsDisabled} onChange={(event) => onSmtpChange({ port: event.target.value })} /></FormField>
               <FormField label="i18n:govoplan-core.security.f25ce1b8"><SecuritySelect value={smtpSecurity} disabled={smtpFieldsDisabled} onChange={patchSmtpSecurity} /></FormField>
+              <FormField label="i18n:govoplan-core.timeout_seconds.0bfc6553"><input type="number" min={1} value={stringValue(smtp.timeout_seconds)} disabled={smtpFieldsDisabled} onChange={(event) => onSmtpChange({ timeout_seconds: event.target.value })} /></FormField>
               </>
               }
               {showCredentialFields &&
@@ -336,9 +318,7 @@ export default function MailServerSettingsPanel({
                 onChange={patchSmtpCredentials}
                 disabled={smtpCredentialFieldsDisabled}
                 savedPassword={smtpPasswordSaved}
-                savedPasswordPlaceholder={smtpSavedPasswordPlaceholder}
-                heading="i18n:govoplan-core.credentials.dd097a22"
-                headingClassName="mail-server-field-heading" />
+                savedPasswordPlaceholder={smtpSavedPasswordPlaceholder} />
               }
             </div>
             {onTestSmtp &&
@@ -355,10 +335,10 @@ export default function MailServerSettingsPanel({
             <div className="form-grid compact responsive-form-grid mail-server-form-grid">
               {showServerFields &&
               <>
-              <div className="mail-server-field-heading">i18n:govoplan-core.server.cb0cb170</div>
-              <FormField label="i18n:govoplan-core.host.3960ec4c"><input value={stringValue(imap.host)} disabled={imapFieldsDisabled} onChange={(event) => onImapChange({ host: event.target.value })} /></FormField>
+              <FormField label="i18n:govoplan-core.server.cb0cb170" help="i18n:govoplan-core.mail_server_hostname_or_ip_address_for_the_selec.596c2d69"><input value={stringValue(imap.host)} disabled={imapFieldsDisabled} onChange={(event) => onImapChange({ host: event.target.value })} /></FormField>
               <FormField label="i18n:govoplan-core.port.fe035157"><input type="number" min={1} max={65535} value={imapPort} disabled={imapFieldsDisabled} onChange={(event) => onImapChange({ port: event.target.value })} /></FormField>
               <FormField label="i18n:govoplan-core.security.f25ce1b8"><SecuritySelect value={imapSecurity} disabled={imapFieldsDisabled} onChange={patchImapSecurity} /></FormField>
+              <FormField label="i18n:govoplan-core.timeout_seconds.0bfc6553"><input type="number" min={1} value={stringValue(imap.timeout_seconds)} disabled={imapFieldsDisabled} onChange={(event) => onImapChange({ timeout_seconds: event.target.value })} /></FormField>
               </>
               }
               {showCredentialFields &&
@@ -367,9 +347,7 @@ export default function MailServerSettingsPanel({
                 onChange={patchImapCredentials}
                 disabled={imapCredentialFieldsDisabled}
                 savedPassword={imapPasswordSaved}
-                savedPasswordPlaceholder={imapSavedPasswordPlaceholder}
-                heading="i18n:govoplan-core.credentials.dd097a22"
-                headingClassName="mail-server-field-heading" />
+                savedPasswordPlaceholder={imapSavedPasswordPlaceholder} />
               }
             </div>
             {onTestImap &&
@@ -381,41 +359,6 @@ export default function MailServerSettingsPanel({
           </section>
         }
 
-        {activeSection === "advanced" &&
-        <section className="mail-server-subsection" role="tabpanel" aria-label="i18n:govoplan-core.advanced_mail_settings.1f69439a">
-            <div className="form-grid compact responsive-form-grid mail-server-form-grid mail-server-advanced-grid">
-              {mockToggle &&
-            <div className="mail-server-field-span mail-server-toggle-row">
-                  <ToggleSwitch
-                label={mockToggle.label ?? "i18n:govoplan-core.mock_server_settings.9361d5c5"}
-                checked={mockToggle.checked}
-                disabled={disabled || mockToggle.disabled}
-                onChange={mockToggle.onChange} />
-              
-                </div>
-            }
-              <FormField label="i18n:govoplan-core.smtp_timeout_seconds.ac87c8d2"><input type="number" min={1} value={stringValue(smtp.timeout_seconds)} disabled={smtpFieldsDisabled} onChange={(event) => onSmtpChange({ timeout_seconds: event.target.value })} /></FormField>
-              <FormField label="i18n:govoplan-core.imap_timeout_seconds.489af2a4"><input type="number" min={1} value={stringValue(imap.timeout_seconds)} disabled={imapFieldsDisabled} onChange={(event) => onImapChange({ timeout_seconds: event.target.value })} /></FormField>
-              {append &&
-            <div className="mail-server-field-span mail-server-toggle-row mail-server-plain-toggle-row">
-                  <ToggleSwitch label="i18n:govoplan-core.append_successfully_sent_messages_to_sent.002fd67e" checked={append.enabled} disabled={disabled || append.disabled} onChange={append.onEnabledChange} />
-                </div>
-            }
-              <FormField label="i18n:govoplan-core.append_target_folder.0aaacc0c" help={appendTargetHelp}>
-                <div className="field-with-action mail-server-folder-field">
-                  <input
-                  value={appendTargetFolder}
-                  disabled={appendTargetDisabled}
-                  onChange={(event) => append ? append.onFolderChange(event.target.value) : onImapChange({ sent_folder: event.target.value })}
-                  placeholder="i18n:govoplan-core.auto.0d612c12" />
-                
-                  {canLookupAppendFolders && <Button type="button" variant="primary" onClick={onLookupFolders} disabled={imapActionsDisabled || busyAction === "folders"}>{busyAction === "folders" ? "i18n:govoplan-core.looking_up.5fc6d2a2" : folderLookupLabel}</Button>}
-                </div>
-              </FormField>
-              {canLookupAppendFolders && <MailServerFolderLookupResultView result={folderLookupResult} disabled={useDetectedFolderDisabled || appendTargetDisabled} onUseDetected={onUseDetectedFolder} />}
-            </div>
-          </section>
-        }
       </div>
     </div>);
 
@@ -437,20 +380,18 @@ export function MailServerActionResult({ result, floating = false }: {result: Ma
 export function MailServerFolderLookupResultView({
   result,
   disabled = false,
-  onUseDetected
-
-
-
-
-}: {result: MailServerFolderLookupResult | null | undefined;disabled?: boolean;onUseDetected?: () => void;}) {
+  onUseDetected,
+  compact = true,
+  floatingFailures = false
+}: {result: MailServerFolderLookupResult | null | undefined;disabled?: boolean;onUseDetected?: () => void;compact?: boolean;floatingFailures?: boolean;}) {
   if (!result) return null;
   if (!result.ok) {
-    return <DismissibleAlert tone="danger" resetKey={result.message}>{result.message}</DismissibleAlert>;
+    return <DismissibleAlert tone="warning" compact={compact} resetKey={result.message} floating={floatingFailures}>{result.message}</DismissibleAlert>;
   }
 
   const folders = result.folders ?? [];
   return (
-    <DismissibleAlert tone="success" resetKey={`${result.message}:${result.detected_sent_folder || ""}`}>
+    <DismissibleAlert tone="success" compact={compact} resetKey={`${result.message}:${result.detected_sent_folder || ""}`}>
       <p>{result.message}</p>
       <p>i18n:govoplan-core.detected_sent_folder.cbf8ec8d <strong>{result.detected_sent_folder || "-"}</strong></p>
       {result.detected_sent_folder && onUseDetected && <Button type="button" onClick={onUseDetected} disabled={disabled}>i18n:govoplan-core.use_detected_folder.5ec4965c</Button>}
diff --git a/webui/src/layout/AppShell.tsx b/webui/src/layout/AppShell.tsx
index cf3f309..00fcd51 100644
--- a/webui/src/layout/AppShell.tsx
+++ b/webui/src/layout/AppShell.tsx
@@ -13,6 +13,7 @@ type Props = {
   publicMode?: boolean;
   navItems?: PlatformNavItem[];
   maintenanceMode?: { enabled: boolean; message?: string | null };
+  backendReachable?: boolean;
 };
 
 export default function AppShell({
@@ -23,7 +24,8 @@ export default function AppShell({
   onAuthChange,
   publicMode = false,
   navItems = [],
-  maintenanceMode
+  maintenanceMode,
+  backendReachable = true
 }: Props) {
   const location = useLocation();
 
@@ -32,7 +34,7 @@ export default function AppShell({
       <div className="app-shell public-shell">
         <IconRail compact auth={auth} navItems={navItems} />
         <div className="app-main public-main">
-          <Titlebar settings={settings} auth={auth} onSettingsChange={onSettingsChange} onAuthChange={onAuthChange} maintenanceMode={maintenanceMode} />
+          <Titlebar settings={settings} auth={auth} onSettingsChange={onSettingsChange} onAuthChange={onAuthChange} maintenanceMode={maintenanceMode} backendReachable={backendReachable} />
           <main className="public-content">{children}</main>
         </div>
       </div>
@@ -43,7 +45,7 @@ export default function AppShell({
     <div className="app-shell">
       <IconRail auth={auth} navItems={navItems} />
       <div className="app-main">
-        <Titlebar settings={settings} auth={auth} onSettingsChange={onSettingsChange} onAuthChange={onAuthChange} maintenanceMode={maintenanceMode} />
+        <Titlebar settings={settings} auth={auth} onSettingsChange={onSettingsChange} onAuthChange={onAuthChange} maintenanceMode={maintenanceMode} backendReachable={backendReachable} />
         <BreadcrumbBar pathname={location.pathname} />
         <main className="app-content">{children}</main>
       </div>
diff --git a/webui/src/layout/Titlebar.tsx b/webui/src/layout/Titlebar.tsx
index 99ddc0b..7b50a54 100644
--- a/webui/src/layout/Titlebar.tsx
+++ b/webui/src/layout/Titlebar.tsx
@@ -23,9 +23,10 @@ type Props = {
   onSettingsChange: (settings: ApiSettings) => void;
   onAuthChange: (auth: AuthUpdate | null, accessToken?: string) => void;
   maintenanceMode?: {enabled: boolean;message?: string | null;};
+  backendReachable?: boolean;
 };
 
-export default function Titlebar({ settings, auth, onAuthChange, maintenanceMode }: Props) {
+export default function Titlebar({ settings, auth, onAuthChange, maintenanceMode, backendReachable = true }: Props) {
   const navigate = useGuardedNavigate();
   const { requestNavigation } = useUnsavedChanges();
   const [accountOpen, setAccountOpen] = useState(false);
@@ -161,7 +162,15 @@ export default function Titlebar({ settings, auth, onAuthChange, maintenanceMode
 
   return (
     <header className="titlebar">
-      {maintenanceMode?.enabled &&
+      {!backendReachable ?
+      <div
+        className="backend-offline-topbar-alert"
+        role="status"
+        aria-live="polite"
+        title="System not reachable / offline!">
+          System not reachable / offline!
+        </div> :
+      maintenanceMode?.enabled &&
       <button
         type="button"
         className="maintenance-topbar-link"
diff --git a/webui/src/styles/components.css b/webui/src/styles/components.css
index 0235bd6..83fa4df 100644
--- a/webui/src/styles/components.css
+++ b/webui/src/styles/components.css
@@ -1564,20 +1564,31 @@
   box-shadow: var(--shadow-thumb);
   transition: transform .16s ease;
 }
-.toggle-switch-input:checked + .toggle-switch-track {
+.toggle-switch-input:checked ~ .toggle-switch-track {
   border-color: var(--primary);
   background: var(--primary);
 }
-.toggle-switch-input:checked + .toggle-switch-track .toggle-switch-thumb {
+.toggle-switch-input:checked ~ .toggle-switch-track .toggle-switch-thumb {
   transform: translateX(18px);
 }
-.toggle-switch-input:focus-visible + .toggle-switch-track {
+.toggle-switch-input:focus-visible ~ .toggle-switch-track {
   box-shadow: var(--primary-focus-ring-soft), var(--shadow-control-inset-strong);
 }
-.toggle-switch-input:disabled + .toggle-switch-track {
+.toggle-switch-input:disabled ~ .toggle-switch-track {
   filter: grayscale(.15);
   opacity: .7;
 }
+.toggle-switch-state-label {
+  color: var(--muted);
+  font-size: 13px;
+  font-weight: 650;
+  line-height: 1;
+  white-space: nowrap;
+}
+.toggle-switch-state-label[data-selected="true"] {
+  color: var(--text-strong);
+  font-weight: 800;
+}
 .toggle-switch-copy {
   display: grid;
   gap: 2px;
@@ -1949,6 +1960,21 @@
   flex: 1 1 auto;
 }
 
+.compact-alert {
+  padding: 10px 12px;
+  margin-bottom: 10px;
+  font-size: 13px;
+  line-height: 1.4;
+}
+
+.compact-alert .alert-message > :first-child {
+  margin-top: 0;
+}
+
+.compact-alert .alert-message > :last-child {
+  margin-bottom: 0;
+}
+
 .alert-floating-stack {
   position: fixed;
   top: 131px;
@@ -2489,6 +2515,18 @@
   background: var(--surface);
 }
 
+.message-display-attachment-row > svg {
+  margin-top: 1px;
+}
+
+.message-display-attachment-row.is-linked > svg {
+  color: var(--green);
+}
+
+.message-display-attachment-row.is-unlinked > svg {
+  color: var(--red);
+}
+
 .message-display-attachment-row > span {
   display: grid;
   gap: 3px;
@@ -2580,9 +2618,9 @@
   gap: 12px;
 }
 .mail-server-segmented-control {
-  grid-template-columns: repeat(3, minmax(0, 1fr));
+  grid-template-columns: repeat(2, minmax(0, 1fr));
   justify-self: center;
-  width: min(420px, 100%);
+  width: min(320px, 100%);
 }
 .mail-server-settings-view {
   min-width: 0;
@@ -2610,7 +2648,7 @@
   letter-spacing: .01em;
 }
 .form-grid.compact.mail-server-form-grid {
-  grid-template-columns: repeat(3, minmax(0, 1fr));
+  grid-template-columns: repeat(2, minmax(0, 1fr));
 }
 .mail-server-form-grid {
   align-items: start;
@@ -2668,7 +2706,7 @@
   .mail-server-settings-grid { grid-template-columns: 1fr; }
 }
 @media (max-width: 900px) {
-  .form-grid.compact.mail-server-form-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
+  .mail-server-segmented-control { width: min(320px, 100%); }
 }
 @media (max-width: 720px) {
   .credential-panel-grid { grid-template-columns: 1fr; }
diff --git a/webui/src/styles/layout.css b/webui/src/styles/layout.css
index 467a400..750c323 100644
--- a/webui/src/styles/layout.css
+++ b/webui/src/styles/layout.css
@@ -36,8 +36,11 @@
 .titlebar-notification-button { position: relative; }
 .titlebar-notification-badge { position: absolute; top: 4px; right: 3px; min-width: 16px; height: 16px; box-sizing: border-box; display: inline-flex; align-items: center; justify-content: center; padding: 0 4px; border: 2px solid var(--titlebar-bg); border-radius: 999px; background: var(--red); color: var(--on-accent); font-size: 10px; font-weight: 800; line-height: 1; transform: translate(35%, -35%); }
 .account-pill { color: var(--text); }
-.maintenance-topbar-link { position: absolute; left: 50%; top: 50%; transform: translate(-50%, -50%); border: 1px solid var(--warning-border-soft); background: var(--warning-bg); color: var(--warning-text); border-radius: 6px; min-height: 32px; padding: 0 14px; font: inherit; font-weight: 800; box-shadow: 0 1px 2px var(--hover-tint); cursor: pointer; z-index: 1; }
+.maintenance-topbar-link,
+.backend-offline-topbar-alert { position: absolute; left: 50%; top: 50%; transform: translate(-50%, -50%); border-radius: 6px; min-height: 32px; padding: 0 14px; display: inline-flex; align-items: center; justify-content: center; font: inherit; font-weight: 800; box-shadow: 0 1px 2px var(--hover-tint); z-index: 1; white-space: nowrap; }
+.maintenance-topbar-link { border: 1px solid var(--warning-border-soft); background: var(--warning-bg); color: var(--warning-text); cursor: pointer; }
 .maintenance-topbar-link:hover { background: var(--warning-bg-hover); color: var(--warning-text-hover); }
+.backend-offline-topbar-alert { border: 1px solid var(--danger-border-deep); background: var(--red); color: var(--on-accent); }
 .language-menu-button { min-width: 54px; justify-content: center; font-weight: 800; }
 .language-menu-code, .language-option-code { font-size: 12px; letter-spacing: .06em; text-transform: uppercase; }
 .language-menu { min-width: 210px; }
diff --git a/webui/tests/mail-components.test.tsx b/webui/tests/mail-components.test.tsx
index 5455333..deb97e9 100644
--- a/webui/tests/mail-components.test.tsx
+++ b/webui/tests/mail-components.test.tsx
@@ -16,12 +16,34 @@ import { renderToStaticMarkup } from "react-dom/server";
 import CredentialPanel from "../src/components/CredentialPanel";
 import PasswordField from "../src/components/PasswordField";
 import MessageDisplayPanel from "../src/components/MessageDisplayPanel";
-import MailServerSettingsPanel from "../src/components/mail/MailServerSettingsPanel";
+import MailServerSettingsPanel, { MailServerFolderLookupResultView, resolveMailServerSettingsActiveSection } from "../src/components/mail/MailServerSettingsPanel";
 import EmailAddressInput from "../src/components/email/EmailAddressInput";
 import { PlatformLanguageProvider } from "../src/i18n/LanguageContext";
 
 function noop() {}
 
+const allMailServerSections = ["smtp", "imap"] as const;
+assertEqual(
+  resolveMailServerSettingsActiveSection("imap", "smtp", "smtp", allMailServerSections),
+  "imap",
+  "user-selected mail settings section is not reset to initialSection"
+);
+assertEqual(
+  resolveMailServerSettingsActiveSection("smtp", "imap", "smtp", allMailServerSections),
+  "imap",
+  "changed initialSection is applied when parent intentionally changes it"
+);
+assertEqual(
+  resolveMailServerSettingsActiveSection("imap", "smtp", "smtp", ["smtp"] as const),
+  "smtp",
+  "active mail settings section falls back when hidden by visibleSections"
+);
+assertEqual(
+  resolveMailServerSettingsActiveSection("smtp", "imap", "imap", ["smtp"] as const),
+  "smtp",
+  "hidden initialSection falls back to the first visible section"
+);
+
 const savedPassword = renderToStaticMarkup(
   <PasswordField value="" saved savedPlaceholder="Saved password configured" onValueChange={noop} />
 );
@@ -75,20 +97,14 @@ const settingsPanel = renderToStaticMarkup(
     imapSavedPasswordPlaceholder="Saved IMAP password"
     onTestSmtp={noop}
     onTestImap={noop}
-    onLookupFolders={noop}
-    folderLookupResult={{
-      ok: true,
-      protocol: "imap",
-      message: "Folders loaded",
-      detected_sent_folder: "Sent",
-      folders: [{ name: "INBOX", flags: [] }, { name: "Sent", flags: ["\\Sent"] }]
-    }}
-    onUseDetectedFolder={noop}
   />
 );
 assert(settingsPanel.includes("i18n:govoplan-core.test_smtp.e5697981"), "SMTP test action is rendered");
-assert(settingsPanel.includes("i18n:govoplan-core.server.cb0cb170"), "server heading is rendered");
-assert(settingsPanel.includes("i18n:govoplan-core.credentials.dd097a22"), "credentials heading is rendered");
+assert(settingsPanel.includes("i18n:govoplan-core.server.cb0cb170"), "server field is rendered");
+assert(settingsPanel.includes("i18n:govoplan-core.username.84c29015"), "username field is rendered");
+assert(settingsPanel.includes("i18n:govoplan-core.password.8be3c943"), "password field is rendered");
+assert(settingsPanel.includes("i18n:govoplan-core.timeout_seconds.0bfc6553"), "timeout field is rendered with SMTP server settings");
+assert(!settingsPanel.includes("i18n:govoplan-core.advanced.4d064726"), "advanced section tab is not rendered");
 assert(!settingsPanel.includes("Enable IMAP"), "legacy IMAP enable toggle is not rendered");
 assert(settingsPanel.includes('placeholder="Saved SMTP password"'), "SMTP saved credential placeholder is rendered");
 
@@ -102,77 +118,45 @@ const imapSettingsPanel = renderToStaticMarkup(
     imapPasswordSaved
     imapSavedPasswordPlaceholder="Saved IMAP password"
     onTestImap={noop}
-    onLookupFolders={noop}
-    folderLookupResult={{
-      ok: true,
-      protocol: "imap",
-      message: "Folders loaded",
-      detected_sent_folder: "Sent",
-      folders: [{ name: "INBOX", flags: [] }, { name: "Sent", flags: ["\\Sent"] }]
-    }}
-    onUseDetectedFolder={noop}
   />
 );
 assert(imapSettingsPanel.includes("i18n:govoplan-core.test_imap.ef1bd79c"), "IMAP test action is rendered");
-assert(imapSettingsPanel.includes("i18n:govoplan-core.server.cb0cb170"), "IMAP server heading is rendered");
-assert(imapSettingsPanel.includes("i18n:govoplan-core.credentials.dd097a22"), "IMAP credentials heading is rendered");
+assert(imapSettingsPanel.includes("i18n:govoplan-core.server.cb0cb170"), "IMAP server field is rendered");
+assert(imapSettingsPanel.includes("i18n:govoplan-core.username.84c29015"), "IMAP username field is rendered");
+assert(imapSettingsPanel.includes("i18n:govoplan-core.password.8be3c943"), "IMAP password field is rendered");
+assert(imapSettingsPanel.includes("i18n:govoplan-core.timeout_seconds.0bfc6553"), "IMAP timeout field is rendered with IMAP server settings");
 assert(!imapSettingsPanel.includes("Enable IMAP"), "legacy IMAP enable toggle is not rendered in IMAP tab");
 assert(!imapSettingsPanel.includes("i18n:govoplan-core.folders.c603ab65"), "folder lookup action is not rendered in the IMAP tab");
 assert(imapSettingsPanel.includes('placeholder="Saved IMAP password"'), "IMAP saved credential placeholder is rendered");
 assert(!imapSettingsPanel.includes("Folders loaded"), "folder lookup result is not rendered in the IMAP tab");
 assert(!imapSettingsPanel.includes("Default sent folder"), "default sent folder field is not rendered");
 
-const advancedSettingsPanel = renderToStaticMarkup(
-  <MailServerSettingsPanel
-    initialSection="advanced"
-    smtp={{ host: "smtp.example.org", security: "starttls" }}
-    imap={{ host: "imap.example.org", security: "tls", sent_folder: "Sent" }}
-    onSmtpChange={noop}
-    onImapChange={noop}
-    onLookupFolders={noop}
-    folderLookupResult={{
+const folderLookupError = renderToStaticMarkup(
+  <MailServerFolderLookupResultView result={{ ok: false, protocol: "imap", message: "IMAP lookup timed out", folders: [] }} />
+);
+assert(folderLookupError.includes("compact-alert"), "folder lookup errors use the compact shared alert style");
+assert(folderLookupError.includes("warning"), "folder lookup errors are warnings, not page-level danger alerts");
+assert(folderLookupError.includes("IMAP lookup timed out"), "folder lookup error message is rendered");
+
+const floatingFolderLookupError = renderToStaticMarkup(
+  <MailServerFolderLookupResultView result={{ ok: false, protocol: "imap", message: "IMAP lookup timed out", folders: [] }} floatingFailures />
+);
+assert(floatingFolderLookupError.includes("alert-floating"), "folder lookup errors can be rendered in the floating alert stack");
+
+const folderLookupSuccess = renderToStaticMarkup(
+  <MailServerFolderLookupResultView
+    result={{
       ok: true,
       protocol: "imap",
       message: "Folders loaded",
       detected_sent_folder: "Sent",
       folders: [{ name: "INBOX", flags: [] }, { name: "Sent", flags: ["\\Sent"] }]
     }}
-    onUseDetectedFolder={noop}
+    onUseDetected={noop}
   />
 );
-assert(advancedSettingsPanel.includes("i18n:govoplan-core.append_target_folder.0aaacc0c"), "append target folder is the advanced IMAP folder field");
-assert(advancedSettingsPanel.includes("i18n:govoplan-core.folders.c603ab65"), "folder lookup action is rendered near append target folder");
-assert(advancedSettingsPanel.includes("Folders loaded"), "folder lookup result is rendered in Advanced");
-assert(advancedSettingsPanel.includes("i18n:govoplan-core.use_detected_folder.5ec4965c"), "detected folder action is rendered near append target folder");
-assert(advancedSettingsPanel.includes('value="Sent"'), "append target folder uses IMAP sent folder value without append override");
-
-const disabledAppendFolderPanel = renderToStaticMarkup(
-  <MailServerSettingsPanel
-    initialSection="advanced"
-    smtp={{ host: "smtp.example.org", security: "starttls" }}
-    imap={{ host: "imap.example.org", security: "tls", sent_folder: "Sent" }}
-    onSmtpChange={noop}
-    onImapChange={noop}
-    onLookupFolders={noop}
-    folderLookupResult={{
-      ok: true,
-      protocol: "imap",
-      message: "Folders loaded",
-      detected_sent_folder: "Sent",
-      folders: [{ name: "Sent", flags: ["\\Sent"] }]
-    }}
-    onUseDetectedFolder={noop}
-    append={{
-      enabled: true,
-      folder: "Sent",
-      folderDisabled: true,
-      onEnabledChange: noop,
-      onFolderChange: noop
-    }}
-  />
-);
-assert(!disabledAppendFolderPanel.includes("i18n:govoplan-core.folders.c603ab65"), "folder lookup action is hidden when append target is disabled");
-assert(!disabledAppendFolderPanel.includes("i18n:govoplan-core.use_detected_folder.5ec4965c"), "detected folder action is hidden when append target is disabled");
+assert(folderLookupSuccess.includes("compact-alert"), "folder lookup success uses the compact shared alert style");
+assert(folderLookupSuccess.includes("Folders loaded"), "folder lookup success message is rendered");
 
 const smtpServerOnlyPanel = renderToStaticMarkup(
   <MailServerSettingsPanel
@@ -185,7 +169,7 @@ const smtpServerOnlyPanel = renderToStaticMarkup(
   />
 );
 assert(smtpServerOnlyPanel.includes("i18n:govoplan-core.server.cb0cb170"), "focused server panel renders server fields");
-assert(!smtpServerOnlyPanel.includes("i18n:govoplan-core.credentials.dd097a22"), "focused server panel hides credential fields");
+assert(!smtpServerOnlyPanel.includes("i18n:govoplan-core.username.84c29015"), "focused server panel hides credential fields");
 assert(!smtpServerOnlyPanel.includes("i18n:govoplan-core.mail_server_settings_sections.40a163b7"), "single focused section hides section switcher");
 assert(!smtpServerOnlyPanel.includes("imap.example.org"), "focused SMTP server panel does not render IMAP fields");
 
@@ -202,7 +186,7 @@ const imapCredentialsOnlyPanel = renderToStaticMarkup(
     imapSavedPasswordPlaceholder="Saved IMAP password"
   />
 );
-assert(imapCredentialsOnlyPanel.includes("i18n:govoplan-core.credentials.dd097a22"), "focused credentials panel renders credential fields");
+assert(imapCredentialsOnlyPanel.includes("i18n:govoplan-core.username.84c29015"), "focused credentials panel renders credential fields");
 assert(!imapCredentialsOnlyPanel.includes("i18n:govoplan-core.server.cb0cb170"), "focused credentials panel hides server fields");
 assert(imapCredentialsOnlyPanel.includes('placeholder="Saved IMAP password"'), "focused credentials panel preserves saved password UX");
 assert(!imapCredentialsOnlyPanel.includes("smtp.example.org"), "focused IMAP credentials panel does not render SMTP fields");