diff --git a/apps/ScreenShareWeb/src/App.css b/apps/ScreenShareWeb/src/App.css
index 94ca4ee..5763ba7 100644
--- a/apps/ScreenShareWeb/src/App.css
+++ b/apps/ScreenShareWeb/src/App.css
@@ -8,6 +8,11 @@
   width: min(460px, calc(100% - 32px));
 }
 
+.app-shell.in-room {
+  width: min(1440px, calc(100% - 32px));
+  padding: 20px 0;
+}
+
 .app-header {
   display: flex;
   align-items: flex-start;
@@ -240,7 +245,7 @@ button:disabled {
   background: #181a29;
 }
 
-.screen-frame figcaption {
+.screen-caption {
   padding: 8px 10px;
   color: #e8e9f4;
   font-size: 0.82rem;
@@ -253,6 +258,84 @@ button:disabled {
   background: #10111b;
 }
 
+.room-toolbar {
+  display: flex;
+  justify-content: flex-end;
+  gap: 10px;
+  margin-bottom: 14px;
+}
+
+.room-toolbar .share-button {
+  margin-left: 0;
+}
+
+.screen-stage {
+  display: grid;
+  min-height: min(72vh, 760px);
+  overflow: hidden;
+  border: 1px solid #dedfed;
+  border-radius: 16px;
+  background: #10111b;
+}
+
+.screen-stage .screen-frame {
+  display: grid;
+  grid-template-rows: auto minmax(0, 1fr);
+  min-height: 0;
+  border-radius: 0;
+}
+
+.screen-stage .media-slot,
+.screen-stage .media-slot video {
+  width: 100%;
+  height: 100%;
+  max-height: none;
+  object-fit: contain;
+}
+
+.stage-empty {
+  margin: auto;
+  color: #c3c5d5;
+}
+
+.screen-thumbnails {
+  display: flex;
+  gap: 12px;
+  overflow-x: auto;
+  padding: 14px 2px 2px;
+}
+
+.screen-thumbnail {
+  flex: 0 0 230px;
+  min-height: 0;
+  overflow: hidden;
+  padding: 0;
+  border: 2px solid transparent;
+  border-radius: 10px;
+  background: #181a29;
+  text-align: left;
+}
+
+.screen-thumbnail:hover,
+.screen-thumbnail:focus-visible {
+  border-color: #7669ed;
+  outline: none;
+}
+
+.screen-thumbnail .screen-frame {
+  border-radius: 8px;
+}
+
+.screen-thumbnail .screen-caption {
+  padding: 6px 8px;
+  font-size: 0.73rem;
+}
+
+.screen-thumbnail .media-slot video {
+  height: 128px;
+  object-fit: contain;
+}
+
 .development-note {
   margin: 28px auto 0;
   max-width: 780px;
@@ -279,4 +362,12 @@ button:disabled {
   .share-button {
     margin-left: 0;
   }
+
+  .screen-stage {
+    min-height: 52vh;
+  }
+
+  .screen-thumbnail {
+    flex-basis: 170px;
+  }
 }
diff --git a/apps/ScreenShareWeb/src/App.tsx b/apps/ScreenShareWeb/src/App.tsx
index c77ddf9..3a5ff8f 100644
--- a/apps/ScreenShareWeb/src/App.tsx
+++ b/apps/ScreenShareWeb/src/App.tsx
@@ -22,12 +22,12 @@ type TokenResponse = {
   role: Role
 }
 
-type ScreenFeed = { track: Track; label: string }
+type ScreenFeed = { id: string; track: Track; label: string; isLocal: boolean }
 type RoomHistoryItem = { id: string; title: string; visitedAt: string }
 
 const ROOM_HISTORY_KEY = 'screen-share-room-history'
 
-function ScreenTrack({ track, label }: ScreenFeed) {
+function ScreenTrack({ track, label, variant = 'main' }: ScreenFeed & { variant?: 'main' | 'thumbnail' }) {
   const mediaContainerRef = useRef<HTMLDivElement>(null)
 
   useEffect(() => {
@@ -43,10 +43,10 @@ function ScreenTrack({ track, label }: ScreenFeed) {
   }, [track])
 
   return (
-    <figure className="screen-frame">
-      <figcaption>{label}</figcaption>
+    <div className={'screen-frame ' + variant}>
+      <div className="screen-caption">{label}</div>
       <div className="media-slot" ref={mediaContainerRef} />
-    </figure>
+    </div>
   )
 }
 
@@ -90,9 +90,9 @@ function App() {
   const [connectionState, setConnectionState] = useState<'idle' | 'connecting' | 'connected'>('idle')
   const [roomRole, setRoomRole] = useState<Role | null>(null)
   const [isSharing, setIsSharing] = useState(false)
-  const [remoteCount, setRemoteCount] = useState(0)
   const [localScreen, setLocalScreen] = useState<ScreenFeed | null>(null)
   const [remoteScreens, setRemoteScreens] = useState<ScreenFeed[]>([])
+  const [activeScreenId, setActiveScreenId] = useState<string | null>(null)
   const [createdInvite, setCreatedInvite] = useState('')
   const [error, setError] = useState('')
 
@@ -114,10 +114,6 @@ function App() {
     setSession(next)
   }
 
-  function refreshRemoteCount(room: Room) {
-    setRemoteCount(room.remoteParticipants.size)
-  }
-
   function rememberRoom(room: Pick<RoomHistoryItem, 'id' | 'title'>) {
     setRoomHistory((history) => {
       const next = [
@@ -224,27 +220,38 @@ function App() {
       setLocalScreen(null)
       setRemoteScreens([])
       const room = new Room()
-      room.on(RoomEvent.ParticipantConnected, () => refreshRemoteCount(room))
-      room.on(RoomEvent.ParticipantDisconnected, () => refreshRemoteCount(room))
       room.on(RoomEvent.TrackSubscribed, (track, publication, participant) => {
-        if (track.kind === Track.Kind.Video && publication.source === Track.Source.ScreenShare) {
+        const trackId = track.sid
+        if (track.kind === Track.Kind.Video && publication.source === Track.Source.ScreenShare && trackId) {
           setRemoteScreens((screens) => [
-            ...screens.filter((screen) => screen.track.sid !== track.sid),
-            { track, label: (participant.name || participant.identity) + ' 的屏幕' },
+            ...screens.filter((screen) => screen.track.sid !== trackId),
+            { id: trackId, track, label: (participant.name || participant.identity) + ' 的屏幕', isLocal: false },
           ])
+          setActiveScreenId((current) => current?.startsWith('local-') || !current ? trackId : current)
         }
       })
       room.on(RoomEvent.TrackUnsubscribed, (track) => {
         setRemoteScreens((screens) => screens.filter((screen) => screen.track !== track))
+        if (track.sid) {
+          setActiveScreenId((current) => current === track.sid ? null : current)
+        }
       })
       room.on(RoomEvent.LocalTrackPublished, (publication) => {
         if (publication.source === Track.Source.ScreenShare && publication.track) {
-          setLocalScreen({ track: publication.track, label: '你正在共享的屏幕' })
+          const localScreenId = 'local-' + publication.track.sid
+          setLocalScreen({
+            id: localScreenId,
+            track: publication.track,
+            label: '你正在共享的屏幕',
+            isLocal: true,
+          })
+          setActiveScreenId((current) => current ?? localScreenId)
           setIsSharing(true)
         }
       })
       room.on(RoomEvent.LocalTrackUnpublished, (publication) => {
         if (publication.source === Track.Source.ScreenShare) {
+          setActiveScreenId((current) => current?.startsWith('local-') ? null : current)
           setLocalScreen(null)
           setIsSharing(false)
         }
@@ -253,7 +260,6 @@ function App() {
         setConnectionState('idle')
         setRoomRole(null)
         setIsSharing(false)
-        setRemoteCount(0)
         setLocalScreen(null)
         setRemoteScreens([])
       })
@@ -262,7 +268,6 @@ function App() {
       roomRef.current = room
       setRoomId(targetRoomId)
       setRoomRole(payload.role)
-      refreshRemoteCount(room)
       setConnectionState('connected')
     } catch (cause) {
       setConnectionState('idle')
@@ -293,6 +298,9 @@ function App() {
 
   const connected = connectionState === 'connected'
   const canShare = roomRole === 'host' || roomRole === 'publisher'
+  const screens = [...(localScreen ? [localScreen] : []), ...remoteScreens]
+  const activeScreen = screens.find((screen) => screen.id === activeScreenId) ?? screens[0]
+  const secondaryScreens = screens.filter((screen) => screen.id !== activeScreen?.id)
 
   if (!session) {
     return (
@@ -323,63 +331,78 @@ function App() {
   }
 
   return (
-    <main className="app-shell">
-      <header className="app-header">
-        <div>
-          <p className="eyebrow">LIVEKIT · 已登录</p>
-          <h1>屏幕共享房间</h1>
-          <p className="subtitle">当前用户：{session.user.displayName}（{session.user.isAdmin ? '管理员' : '普通用户'}）</p>
-        </div>
-        <button type="button" className="secondary" onClick={logout}>退出登录</button>
-      </header>
+    <main className={connected ? 'app-shell in-room' : 'app-shell'}>
+      {!connected && (
+        <>
+          <header className="app-header">
+            <div>
+              <p className="eyebrow">LIVEKIT · 已登录</p>
+              <h1>屏幕共享房间</h1>
+              <p className="subtitle">当前用户：{session.user.displayName}（{session.user.isAdmin ? '管理员' : '普通用户'}）</p>
+            </div>
+            <button type="button" className="secondary" onClick={logout}>退出登录</button>
+          </header>
 
-      {session.user.isAdmin && (
-        <section className="admin-panel">
-          <strong>管理员邀请码</strong>
-          <button type="button" onClick={() => void createInvite('user')}>创建普通用户邀请码</button>
-          <button type="button" onClick={() => void createInvite('admin')}>创建管理员邀请码</button>
-          {createdInvite && <code className="invite-code">{createdInvite}</code>}
-        </section>
-      )}
+          {session.user.isAdmin && (
+            <section className="admin-panel">
+              <strong>管理员邀请码</strong>
+              <button type="button" onClick={() => void createInvite('user')}>创建普通用户邀请码</button>
+              <button type="button" onClick={() => void createInvite('admin')}>创建管理员邀请码</button>
+              {createdInvite && <code className="invite-code">{createdInvite}</code>}
+            </section>
+          )}
 
-      <section className="join-panel room-panel">
-        <label>房间标题<input list="room-title-history" value={roomTitle} onChange={(event) => setRoomTitle(event.target.value)} disabled={connected} placeholder="输入标题以创建或加入" />
-          <datalist id="room-title-history">{roomHistory.map((item) => <option key={item.id} value={item.title} />)}</datalist>
-        </label>
-        <button type="button" className="primary" onClick={() => void createRoom()} disabled={connected}>创建房间</button>
-        {!connected
-          ? <button type="button" className="secondary" onClick={() => void joinRoomByTitle()} disabled={connectionState === 'connecting'}>{connectionState === 'connecting' ? '正在连接…' : '按标题加入'}</button>
-          : <button type="button" className="secondary" onClick={leaveRoom}>离开房间</button>}
-        <label className="advanced-field">房间 ID（备用）<input value={roomId} onChange={(event) => setRoomId(event.target.value)} disabled={connected} placeholder="UUID" /></label>
-        {!connected && <button type="button" className="secondary id-join" onClick={() => void connectRoom()} disabled={connectionState === 'connecting'}>使用 ID 加入</button>}
-      </section>
+          <section className="join-panel room-panel">
+            <label>房间标题<input list="room-title-history" value={roomTitle} onChange={(event) => setRoomTitle(event.target.value)} placeholder="输入标题以创建或加入" />
+              <datalist id="room-title-history">{roomHistory.map((item) => <option key={item.id} value={item.title} />)}</datalist>
+            </label>
+            <button type="button" className="primary" onClick={() => void createRoom()}>创建房间</button>
+            <button type="button" className="secondary" onClick={() => void joinRoomByTitle()} disabled={connectionState === 'connecting'}>{connectionState === 'connecting' ? '正在连接…' : '按标题加入'}</button>
+            <label className="advanced-field">房间 ID（备用）<input value={roomId} onChange={(event) => setRoomId(event.target.value)} placeholder="UUID" /></label>
+            <button type="button" className="secondary id-join" onClick={() => void connectRoom()} disabled={connectionState === 'connecting'}>使用 ID 加入</button>
+          </section>
 
-      {roomHistory.length > 0 && (
-        <section className="room-history">
-          <strong>最近房间</strong>
-          {roomHistory.map((item) => (
-            <button key={item.id} type="button" onClick={() => {
-              setRoomTitle(item.title)
-              setRoomId(item.id)
-              void connectRoom(item.id)
-            }} disabled={connected}>{item.title}</button>
-          ))}
-        </section>
+          {roomHistory.length > 0 && (
+            <section className="room-history">
+              <strong>最近房间</strong>
+              {roomHistory.map((item) => (
+                <button key={item.id} type="button" onClick={() => {
+                  setRoomTitle(item.title)
+                  setRoomId(item.id)
+                  void connectRoom(item.id)
+                }}>{item.title}</button>
+              ))}
+            </section>
+          )}
+        </>
       )}
 
       {error && <p className="error" role="alert">{error}</p>}
 
-      <section className="status-bar" aria-live="polite">
-        <span className={connected ? 'status online' : 'status'}>{connected ? '已连接' : '未连接'}</span>
-        <span>{roomRole ? '房间角色：' + roomRole : '尚未加入房间'}</span>
-        <span>其他参与者：{remoteCount}</span>
-        {connected && <button type="button" className="share-button" onClick={() => void toggleScreenShare()} disabled={!canShare}>{isSharing ? '停止共享屏幕' : '共享屏幕'}</button>}
-      </section>
+      {connected && (
+        <>
+          <section className="room-toolbar" aria-label="房间控制">
+            {canShare && <button type="button" className="share-button" onClick={() => void toggleScreenShare()}>{isSharing ? '停止共享屏幕' : '共享屏幕'}</button>}
+            <button type="button" className="secondary" onClick={leaveRoom}>离开房间</button>
+          </section>
 
-      <section className="screens">
-        <div className="screen-section"><h2>我的屏幕</h2><div className="video-stack">{localScreen ? <ScreenTrack {...localScreen} /> : <p className="empty">尚未共享屏幕</p>}</div></div>
-        <div className="screen-section"><h2>远端屏幕</h2><div className="video-stack">{remoteScreens.length === 0 ? <p className="empty">等待其他参与者共享屏幕</p> : remoteScreens.map((screen) => <ScreenTrack key={screen.track.sid} {...screen} />)}</div></div>
-      </section>
+          <section className="screen-stage">
+            {activeScreen
+              ? <ScreenTrack {...activeScreen} variant="main" />
+              : <p className="empty stage-empty">等待参与者共享屏幕</p>}
+          </section>
+
+          {secondaryScreens.length > 0 && (
+            <section className="screen-thumbnails" aria-label="副屏幕分享">
+              {secondaryScreens.map((screen) => (
+                <button key={screen.id} type="button" className="screen-thumbnail" onClick={() => setActiveScreenId(screen.id)}>
+                  <ScreenTrack {...screen} variant="thumbnail" />
+                </button>
+              ))}
+            </section>
+          )}
+        </>
+      )}
     </main>
   )
 }