diff --git a/web/index.html b/web/index.html
index bb2f59c..6f14bc3 100644
--- a/web/index.html
+++ b/web/index.html
@@ -28,7 +28,7 @@
   <!-- 聊天主界面，初始隐藏 -->
   <div class="container" id="chat-container" style="display:none;">
     <!-- 左侧房间栏 -->
-    <div class="sidebar">
+    <div class="sidebar" id="sidebar">
       <div class="sidebar-user">
         <span class="avatar" id="sidebar-user-avatar"></span>
         <span class="sidebar-username" id="sidebar-username">My Name</span>
@@ -41,6 +41,7 @@
         <!-- JS填充房间项 -->
       </div>
     </div>
+    <div class="sidebar-resizer" id="sidebar-resizer"></div>
     <!-- 中间聊天区 -->
     <div class="main">
       <div class="main-header" id="main-header">
@@ -78,8 +79,9 @@
         </div>
       </div>
     </div>
+    <div class="rightbar-resizer" id="rightbar-resizer"></div>
     <!-- 右侧在线用户栏 -->
-    <div class="rightbar">
+    <div class="rightbar" id="rightbar">
       <div class="rightbar-header">
         <div class="rightbar-group">
           <div class="group-info">
diff --git a/web/main.js b/web/main.js
index 8427759..2b1e992 100644
--- a/web/main.js
+++ b/web/main.js
@@ -81,23 +81,7 @@ function createUserItem(user, isMe) {
 function handleClientList(idx, list, selfId) {
   const rd = roomsData[idx];
   if (!rd) return;
-  // 记录旧用户ID集合
-  const oldUserIds = new Set((rd.userList || []).map(u => u.clientId));
-  // 新用户ID集合
-  const newUserIds = new Set(list.map(u => u.clientId));
-  // 检查退出用户（旧有，新没有）
-  if (rd.isInitialized) {
-    for (const oldId of oldUserIds) {
-      if (!newUserIds.has(oldId)) {
-        const user = rd.userMap[oldId];
-        const name = user ? (user.userName || user.username || user.name || 'Anonymous') : 'Anonymous';
-        const msg = `${name}已退出`;
-        rd.messages.push({ type: 'system', text: msg });
-        if (activeRoomIndex === idx) addSystemMsg(msg, true);
-      }
-    }
-  }
-  // 更新在线用户列表和映射
+ // 更新在线用户列表和映射
   rd.userList = list;
   rd.userMap = {};
   list.forEach(u => { rd.userMap[u.clientId] = u; });
@@ -114,15 +98,15 @@ function handleClientList(idx, list, selfId) {
     // 基准用户集合
     rd.knownUserIds = new Set(list.map(u => u.clientId));
   }
+
 }
+
 // 调整 handleClientSecured: 立即更新UI，仅在初始化完成后才处理加入提示
 function handleClientSecured(idx, user) {
   const rd = roomsData[idx];
   if (!rd) return;
-  
   // 无论初始化状态如何，始终更新用户映射
   rd.userMap[user.clientId] = user;
-  
   // 检查用户是否已在列表中
   const existingUserIndex = rd.userList.findIndex(u => u.clientId === user.clientId);
   if (existingUserIndex === -1) {
@@ -132,21 +116,17 @@ function handleClientSecured(idx, user) {
     // 用户已在列表中，更新它
     rd.userList[existingUserIndex] = user;
   }
-  
   // 无论初始化状态如何，始终刷新当前房间UI
   if (activeRoomIndex === idx) {
     renderUserList();
     renderMainHeader(); // 也刷新顶部信息栏
   }
-  
   // 仅在初始化完成后才处理加入提示
   if (!rd.isInitialized) {
     return;
   }
-  
   // 检测是否为已知用户集合中不存在的用户
   const isNew = !rd.knownUserIds.has(user.clientId);
-  
   // 提示新用户加入
   if (isNew) {
     rd.knownUserIds.add(user.clientId);
@@ -161,9 +141,14 @@ function handleClientSecured(idx, user) {
 function handleClientLeft(idx, clientId) {
   const rd = roomsData[idx];
   if (!rd) return;
+  const user = rd.userMap[clientId];
+
   rd.userList = rd.userList.filter(u => u.clientId !== clientId);
   delete rd.userMap[clientId];
-  if (activeRoomIndex === idx) renderUserList();
+  rd.messages.push({ type: 'system', text: exitMsg });
+  if (activeRoomIndex === idx) {
+    renderUserList();
+  }
 }
 
 function setStatus(text) {
@@ -764,6 +749,64 @@ window.addEventListener('DOMContentLoaded', () => {
   setupMoreBtnMenu();
   setupImagePreview();
 
+  // sidebar 拖拽宽度调整
+  const sidebar = document.getElementById('sidebar');
+  const resizer = document.getElementById('sidebar-resizer');
+  let isResizing = false;
+  let startX = 0;
+  let startWidth = 0;
+  if (sidebar && resizer) {
+    resizer.addEventListener('mousedown', function(e) {
+      isResizing = true;
+      startX = e.clientX;
+      startWidth = sidebar.offsetWidth;
+      document.body.style.cursor = 'ew-resize';
+      document.body.style.userSelect = 'none';
+    });
+    window.addEventListener('mousemove', function(e) {
+      if (!isResizing) return;
+      let newWidth = startWidth + (e.clientX - startX);
+      newWidth = Math.max(200, Math.min(400, newWidth));
+      sidebar.style.width = newWidth + 'px';
+    });
+    window.addEventListener('mouseup', function() {
+      if (isResizing) {
+        isResizing = false;
+        document.body.style.cursor = '';
+        document.body.style.userSelect = '';
+      }
+    });
+  }
+
+  // rightbar 拖拽宽度调整
+  const rightbar = document.getElementById('rightbar');
+  const rightResizer = document.getElementById('rightbar-resizer');
+  let isRightResizing = false;
+  let rightStartX = 0;
+  let rightStartWidth = 0;
+  if (rightbar && rightResizer) {
+    rightResizer.addEventListener('mousedown', function(e) {
+      isRightResizing = true;
+      rightStartX = e.clientX;
+      rightStartWidth = rightbar.offsetWidth;
+      document.body.style.cursor = 'ew-resize';
+      document.body.style.userSelect = 'none';
+    });
+    window.addEventListener('mousemove', function(e) {
+      if (!isRightResizing) return;
+      let newWidth = rightStartWidth - (e.clientX - rightStartX);
+      newWidth = Math.max(200, Math.min(400, newWidth));
+      rightbar.style.width = newWidth + 'px';
+    });
+    window.addEventListener('mouseup', function() {
+      if (isRightResizing) {
+        isRightResizing = false;
+        document.body.style.cursor = '';
+        document.body.style.userSelect = '';
+      }
+    });
+  }
+
   // 自动聚焦到输入框
   const input = document.querySelector('.input-message-input');
   if (input) {
diff --git a/web/style.css b/web/style.css
index 6eb1de1..3b3a71d 100644
--- a/web/style.css
+++ b/web/style.css
@@ -12,6 +12,31 @@ body {
     background: #fff;
 }
 
+.sidebar {
+    width: 300px;
+    min-width: 200px;
+    max-width: 400px;
+    background: #fff;
+    border-right: 1px solid #e0e0e0;
+    display: flex;
+    flex-direction: column;
+    box-shadow: 2px 0 8px #e0e0e0a0;
+    transition: width 0.15s;
+}
+
+.sidebar-resizer {
+    width: 6px;
+    cursor: ew-resize;
+    background: #ffffff;
+    height: 100vh;
+    position: relative;
+    z-index: 10;
+    transition: background 0.18s;
+}
+.sidebar-resizer:hover {
+    background: #b0b0b0;
+}
+
 /* 左侧用户信息区 */
 .sidebar-user {
     display: flex;
@@ -26,15 +51,6 @@ body {
     color: #222;
 }
 
-.sidebar {
-    width: 300px;
-    background: #fff;
-    border-right: 1px solid #e0e0e0;
-    display: flex;
-    flex-direction: column;
-    box-shadow: 2px 0 8px #e0e0e0a0;
-}
-
 .sidebar .join-room {
     display: flex;
     align-items: center;
@@ -587,11 +603,28 @@ body {
 
 .rightbar {
     width: 250px;
+    min-width: 200px;
+    max-width: 400px;
     background: #fff;
     border-left: 1px solid #e0e0e0;
     display: flex;
     flex-direction: column;
     box-shadow: -2px 0 8px #e0e0e0a0;
+    transition: width 0.15s;
+}
+
+.rightbar-resizer {
+    width: 6px;
+    cursor: ew-resize;
+    background: #ffffff;
+    height: 100vh;
+    position: relative;
+    z-index: 10;
+    user-select: none;
+    transition: background 0.18s;
+}
+.rightbar-resizer:hover {
+    background: #b0b0b0;
 }
 
 .rightbar-header {
@@ -930,4 +963,4 @@ body {
   color: #555;
   display: inline-block;
   text-align: center;
-}
\ No newline at end of file
+}