diff --git a/backend/app/api/v1/chat.py b/backend/app/api/v1/chat.py
index c354fc1..a474ab1 100644
--- a/backend/app/api/v1/chat.py
+++ b/backend/app/api/v1/chat.py
@@ -268,7 +268,9 @@ def _compact_cited_refs(answer: str, retrieved_docs):
                 "citation_id": new_id,
                 "file_path": file_path,
                 "anchor_text": doc.get("anchor_text") or "",
-                "excerpt": doc.get("excerpt") or doc.get("content") or doc.get("anchor_text") or "",
+                # 优先使用命中文档的上下文片段（命中点前后扩展），避免分块边界
+                # 的短文本（如文档末尾残余块）导致引用预览内容过少
+                "excerpt": doc.get("content") or doc.get("excerpt") or doc.get("anchor_text") or "",
             })
         old_to_new[old_id] = new_id
 
diff --git a/frontend/src/pages/Chat/Chat.css b/frontend/src/pages/Chat/Chat.css
index f1b3a99..7f7088a 100644
--- a/frontend/src/pages/Chat/Chat.css
+++ b/frontend/src/pages/Chat/Chat.css
@@ -410,7 +410,8 @@
   vertical-align: super;
   color: #1677ff;
   font-weight: 600;
-  margin: 0 1px;
+  margin: 0 3px;
+  padding: 0 1px;
   cursor: pointer;
 }
 
@@ -578,7 +579,7 @@
 .chat-citation-preview {
   display: flex;
   flex-direction: column;
-  gap: 8px;
+  gap: 10px;
   max-width: 460px;
 }
 
@@ -592,7 +593,7 @@
   overflow: auto;
   word-break: break-word;
   line-height: 1.65;
-  padding: 10px;
+  padding: 12px 14px;
   border: 1px solid var(--border-color);
   border-radius: 8px;
   background: color-mix(in srgb, var(--border-color) 10%, transparent);
@@ -646,13 +647,11 @@
 }
 
 .chat-shell .chat-composer-shell {
-  margin: 0 24px 24px;
+  margin: 0 24px 12px;
 }
 
 .chat-new-composer {
-  min-height: 150px;
-  padding-top: 10px;
-  padding-bottom: 10px;
+  margin-bottom: 12px;
 }
 
 .chat-composer-input {
@@ -697,18 +696,18 @@
 }
 
 .chat-composer-plus {
-  width: 44px;
-  height: 44px;
-  min-width: 44px;
+  width: 32px;
+  height: 32px;
+  min-width: 32px;
   border: 1px solid #f0f0f0;
   border-radius: 50%;
   background: #fff;
-  box-shadow: 0 6px 18px rgba(15, 23, 42, 0.08);
+  box-shadow: 0 2px 8px rgba(15, 23, 42, 0.06);
   color: var(--text-color-secondary);
   display: inline-flex;
   align-items: center;
   justify-content: center;
-  font-size: 24px;
+  font-size: 16px;
   cursor: pointer;
   flex-shrink: 0;
 }
@@ -778,21 +777,19 @@
 }
 
 .chat-send-button {
-  width: 40px !important;
-  height: 40px !important;
-  min-width: 40px !important;
+  width: 32px !important;
+  height: 32px !important;
+  min-width: 32px !important;
   border: 1px solid #bebebe !important;
   background: #d1d1d1 !important;
   color: #fff !important;
   box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.28);
-  font-size: 24px !important;
+  font-size: 14px !important;
   line-height: 1 !important;
-  transform: scale(1.08);
-  transform-origin: center;
 }
 
 .chat-send-button .anticon {
-  font-size: 22px;
+  font-size: 15px;
 }
 
 .chat-send-button:not(:disabled):hover {
@@ -885,10 +882,9 @@ body.dark .chat-search-highlight {
   }
 
   .chat-send-button {
-    width: 48px !important;
-    height: 48px !important;
-    min-width: 48px !important;
-    font-size: 24px !important;
-    transform: scale(1.08);
+    width: 40px !important;
+    height: 40px !important;
+    min-width: 40px !important;
+    font-size: 18px !important;
   }
 }
diff --git a/frontend/src/pages/Chat/Chat.jsx b/frontend/src/pages/Chat/Chat.jsx
index 7e28c16..436eb30 100644
--- a/frontend/src/pages/Chat/Chat.jsx
+++ b/frontend/src/pages/Chat/Chat.jsx
@@ -38,6 +38,7 @@ import 'highlight.js/styles/github.css'
 import { createChatSession, deleteChatMessage, deleteChatSession, getChatMessages, getChatSessions, searchChatMessages, sendChatMessageStream, updateChatSessionTitle } from '@/api/chat'
 import { getMyProjects } from '@/api/project'
 import { getLLMModelConfigs } from '@/api/llmModelConfigs'
+import useUserStore from '@/stores/userStore'
 import './Chat.css'
 
 const { TextArea } = Input
@@ -208,6 +209,7 @@ function MessageActions({ content, onCopy, onDelete }) {
 function Chat() {
   const navigate = useNavigate()
   const location = useLocation()
+  const { user: currentUser } = useUserStore()
   const [searchParams, setSearchParams] = useSearchParams()
   const [sessions, setSessions] = useState([])
   const [projects, setProjects] = useState([])
@@ -232,6 +234,7 @@ function Chat() {
   const [renameSession, setRenameSession] = useState(null)
   const [renameTitle, setRenameTitle] = useState('')
   const messageRefs = useRef(new Map())
+  const messagesEndRef = useRef(null)
   const skipNextOpenSessionRef = useRef(null)
   const searchRequestIdRef = useRef(0)
   const newMode = location.pathname === '/chat/new'
@@ -252,6 +255,19 @@ function Chat() {
   const canCreateSession = Boolean(newQuestion.trim() && currentProject && currentModel)
   const canSendMessage = Boolean(inputValue.trim() && currentSession)
 
+  // 与全站侧边栏/个人资料一致的用户头像：avatar 字段是相对路径时转换为 API 端点
+  const userAvatarUrl = useMemo(() => {
+    const avatar = currentUser?.avatar
+    if (!avatar) return null
+    if (avatar.startsWith('http')) return avatar
+    const parts = avatar.split('/')
+    if (parts.length >= 3) {
+      return `/api/v1/auth/avatar/${parts[0]}/${parts[2]}`
+    }
+    return null
+  }, [currentUser])
+  const userDisplayName = currentUser?.nickname || currentUser?.username
+
   const groupedSessions = useMemo(() => {
     const groups = []
     const groupMap = new Map()
@@ -353,6 +369,11 @@ function Chat() {
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [sessionId, sessions.length, newMode])
 
+  // 新会话打开或消息生成/更新时，自动滚动到对话底部
+  useEffect(() => {
+    messagesEndRef.current?.scrollIntoView({ behavior: 'smooth', block: 'end' })
+  }, [messages, currentSession])
+
   useEffect(() => {
     const target = searchParams.get('message_id')
     if (!target) return
@@ -874,11 +895,16 @@ function Chat() {
                     />
                   )}
                 </div>
-                {isUser && <Avatar className="chat-avatar user" icon={<UserOutlined />} />}
+                {isUser && (
+                  <Avatar className="chat-avatar user" src={userAvatarUrl} style={{ backgroundColor: '#1677ff' }}>
+                    {userDisplayName?.[0]?.toUpperCase() || 'U'}
+                  </Avatar>
+                )}
               </div>
             )
           })
         )}
+        <div ref={messagesEndRef} />
       </div>
       <div className="chat-composer-shell">
         <TextArea