diff --git a/client/electron/src/components/MailView.tsx b/client/electron/src/components/MailView.tsx
index 0bd3163..50e19bc 100644
--- a/client/electron/src/components/MailView.tsx
+++ b/client/electron/src/components/MailView.tsx
@@ -17,6 +17,7 @@ import type { Mail } from '../types';
 import { MailIcon, ShieldIcon, PersonIcon, BotIcon, ForwardIcon, TreeIcon, TagIcon, GaugeIcon, ChevronRightIcon, ChatBubbleIcon } from './icons';
 import { Composer, ComposerChip } from './Composer';
 import { useIsNarrow } from '../hooks/useIsNarrow';
+import { useUIStore } from '../stores/uiStore';
 import AddressInput from './AddressInput';
 import { AttachmentList, AttachmentPicker, type PendingAttachment } from './Attachments';
 import ThreadView from './ThreadView';
@@ -44,6 +45,24 @@ export default function MailView() {
     setThreadOf(null);
   }, [currentMailID]);
 
+  /*
+   * 打开即已读（2026-09-14 用户：「现在邮件需要完全手动标记是否已读而不支持点进去
+   * 自动已读或者回复自动已读」）。
+   *
+   * 两个细节：
+   *  1. 窄屏下 MailView **可能已经渲染但被列表盖住**（NarrowStack 的覆盖层），
+   *     那时用户还没看到它 ⇒ 必须等到真正可见（narrowPane === 'detail'）才标，
+   *     否则"滑过去但没看"的邮件也会被标已读。
+   *  2. 只对 unread 发请求：已读的再标一次是白跑一趟（而且会让接口日志噪音不断）。
+   */
+  const narrowPane = useUIStore(s => s.narrowPane);
+  const visible = !narrow || narrowPane === 'detail';
+  const currentStatus = currentMail?.status;
+  useEffect(() => {
+    if (!visible || !currentMailID || currentStatus !== 'unread') return;
+    void markRead(currentMailID);
+  }, [visible, currentMailID, currentStatus, markRead]);
+
   if (currentSession && currentSessionMails.length > 0) {
     const last = currentSessionMails[currentSessionMails.length - 1];
     // 会话视图的对端是**会话的属性**，不能由「最后一封是谁发的」决定：
@@ -862,6 +881,8 @@ function ReplyBar({
   const [busy, setBusy] = useState(false);
   const [error, setError] = useState<string | null>(null);
   const fetchInbox = useMailStore(s => s.fetchInbox);
+  // 回复即已读要用
+  const markRead = useMailStore(s => s.markRead);
   const fetchSent = useMailStore(s => s.fetchSent);
   const fetchSessions = useSessionStore(s => s.fetchSessions);
   const fetchContacts = useContactStore(s => s.fetchContacts);
@@ -911,6 +932,9 @@ function ReplyBar({
         cc: cc.trim(),
         attachment_ids: attachments.map(a => a.id)
       });
+      // 回复即已读（用户要求）：回了信就等于处理过这封了，不必再手动点一次。
+      // 放在发送成功之后：发送失败时不该把"我处理过了"记下来。
+      void markRead(replyTo.mail_id);
       setBody('');
       setCc('');
       setCcOpen(false);
diff --git a/client/electron/test/components/Sidebar.test.tsx b/client/electron/test/components/Sidebar.test.tsx
index 16bb77b..f1d54c5 100644
--- a/client/electron/test/components/Sidebar.test.tsx
+++ b/client/electron/test/components/Sidebar.test.tsx
@@ -1,4 +1,4 @@
-import { render, screen, fireEvent } from '@testing-library/react';
+import { render, fireEvent } from '@testing-library/react';
 import { beforeEach, describe, expect, it } from 'vitest';
 import Sidebar from '../../src/components/Sidebar';
 import { useUIStore } from '../../src/stores/uiStore';