优化消息内容的换行显示，解决间距过大的问题

src/pages/chat/components/messages/MessageItem.tsx

@@ -1,8 +1,10 @@
 import { Button, Dropdown, Space, Tag, Tooltip, Avatar } from 'antd';
+import { useMemo } from 'react';
 import { CopyOutlined, SyncOutlined } from '@ant-design/icons';
 import type { BranchInfo, ChatMessage } from '../../../../api';
 import type { Agent } from '../../../../api/agents';
 import Markdown from '../../../../components/Markdown';
+import { formatMessageContent } from '../../utils/format';
 import type { CopyMode } from '../../utils/copy';
 import { ReasoningView, RetrievedView, ToolCallView } from './MetaViews';
 import './MessageItem.css';
@@ -21,6 +23,8 @@ export default function MessageItem(props: {
 }) {
   const { message, agentList, currentAgentId, highlighted, branch, busy, onRegenerate, onSwitchBranch, onCopy, isMobile } = props;  
   
+  const formattedContent = useMemo(() => formatMessageContent(message.content), [message.content]);
+  
   const speakerType = (message as any)?.speaker?.type as ('user' | 'agent' | undefined);
   const speakerId = (message as any)?.speaker?.id as string | undefined;
   const isUser = speakerType ? speakerType === 'user' : message.role === 'user';
@@ -66,7 +70,7 @@ export default function MessageItem(props: {
               </span>
             </div>
             <div className={`bubble ${bubbleRole}`}>
-              <Markdown>{message.content}</Markdown>
+              <Markdown>{formattedContent}</Markdown>
               <div className="message-item-actions">
                 {hasBranches && (
                   <Space size={2}>
@@ -86,8 +90,8 @@ export default function MessageItem(props: {
                   trigger={['click']}
                   menu={{
                     items: [
-                      { key: 'plain', label: '复制纯文本', onClick: () => onCopy?.(message.content, 'plain') },
-                      { key: 'markdown', label: '复制 Markdown', onClick: () => onCopy?.(message.content, 'markdown') }
+                      { key: 'plain', label: '复制纯文本', onClick: () => onCopy?.(formattedContent, 'plain') },
+                      { key: 'markdown', label: '复制 Markdown', onClick: () => onCopy?.(formattedContent, 'markdown') }
                     ]
                   }}
                 >
@@ -113,11 +117,11 @@ export default function MessageItem(props: {
         <div className="message-item-user">
           <div className="message-item-user-content-wrapper">
             <div className={`bubble ${bubbleRole}`}>
-              {message.content.includes('![image](') ? (
-                <Markdown>{message.content}</Markdown>
+              {formattedContent.includes('![image](') ? (
+                <Markdown>{formattedContent}</Markdown>
               ) : (
                 <span dangerouslySetInnerHTML={{
-                  __html: message.content.replace(/@([^\s]+)/g, '<span class="mention">@$1</span>')
+                  __html: formattedContent.replace(/@([^\s]+)/g, '<span class="mention">@$1</span>')
                 }} />
               )}
             </div>

src/pages/chat/utils/format.ts

@@ -0,0 +1,18 @@
+/**
+ * 清理消息内容中的冗余换行
+ * 1. 将 3 个及以上的换行替换为 2 个换行
+ * 2. 将特定的 Markdown 块元素前后的双换行替换为单换行，以减少间距
+ */
+export function formatMessageContent(content: string): string {
+  if (!content) return '';
+
+  return content
+    // 将 3 个及以上的换行替换为 2 个
+    .replace(/\n{3,}/g, '\n\n')
+    // 针对 Markdown 块元素，将双换行缩小为单换行
+    // 匹配 \n\n 后面跟着 #, -, *, >, --- 等
+    .replace(/\n\n(?=[#\-*>]|---)/g, '\n')
+    // 匹配 #, -, *, >, --- 后面跟着 \n\n
+    // 由于 JavaScript 不支持所有环境下的 lookbehind，我们先处理上面的
+    .replace(/([#\-*>]|---)\n\n/g, '$1\n');
+}

src/styles.css

@@ -751,7 +751,7 @@ body {
 }
 
 .chat-body .messages-container {
-  max-width: 780px;
+  max-width: 1080px;
   width: 100%;
   margin: 0 auto;
   padding: 16px 12px 80px;
@@ -785,6 +785,7 @@ body {
   border: 0;
   border-bottom-left-radius: 5px;
   box-shadow: none;
+  white-space: normal;
 }
 
 .bubble.assistant p {