fix(HTML预览): 修复链接点击影响父窗口问题

- 注入 <base target="_blank"> 标签
- 智能检测现有 head/html 标签位置注入
- 确保预览中的链接在新标签页打开
- 避免链接影响主应用页面

src/app/chat/[id]/page.tsx

@@ -490,7 +490,7 @@ export default function ChatPage({ params }: PageProps) {
 
         {/* 固定底部输入框 */}
         <div
-          className="sticky bottom-0 pt-4"
+          className="sticky bottom-0 pt-4 z-20"
           style={{
             background: `linear-gradient(to top, var(--color-bg-secondary) 0%, var(--color-bg-secondary) 80%, transparent 100%)`
           }}

src/components/features/ChatInput.tsx

@@ -127,7 +127,7 @@ export function ChatInput({
             onKeyDown={handleKeyDown}
             onPaste={handlePaste}
             placeholder={files.length > 0 ? '添加描述（可选）...' : placeholder}
-            className="w-full border-none outline-none text-base text-[var(--color-text-primary)] bg-transparent py-2 placeholder:text-[var(--color-text-placeholder)]"
+            className="w-full border-none outline-none text-[var(--color-text-primary)] bg-transparent py-2 placeholder:text-[var(--color-text-placeholder)]"
           />
         </div>
 

src/components/features/MessageBubble.tsx

@@ -152,7 +152,7 @@ export function MessageBubble({ message, user, thinkingContent, isStreaming, err
               })}
             </div>
           )}
-          <div className="bg-[var(--color-message-user)] text-[var(--color-text-primary)] px-4 py-3 rounded-md text-base leading-relaxed">
+          <div className="bg-[var(--color-message-user)] text-[var(--color-text-primary)] px-4 py-3 rounded-md leading-relaxed">
             {message.content || ((uploadedImages && uploadedImages.length > 0) || (uploadedDocuments && uploadedDocuments.length > 0) ? '(附件)' : '')}
           </div>
           {/* 悬停显示复制按钮 */}
@@ -216,7 +216,7 @@ export function MessageBubble({ message, user, thinkingContent, isStreaming, err
             </button>
             {thinkingExpanded && (
               <div className="mt-2 p-4 bg-purple-50 border border-purple-200 rounded-lg">
-                <pre className="text-sm text-purple-800 whitespace-pre-wrap font-mono">
+                <pre className="text-purple-800 whitespace-pre-wrap font-mono">
                   {thinkingContent}
                 </pre>
               </div>
@@ -228,13 +228,13 @@ export function MessageBubble({ message, user, thinkingContent, isStreaming, err
         {error && (
           <div className="mb-3 p-4 bg-red-50 border border-red-200 rounded-lg flex items-start gap-3">
             <AlertCircle size={20} className="text-red-500 flex-shrink-0 mt-0.5" />
-            <div className="text-sm text-red-700">{error}</div>
+            <div className="text-red-700">{error}</div>
           </div>
         )}
 
         {/* 主要内容 */}
         <div className="bg-[var(--color-message-assistant-bg)] border border-[var(--color-message-assistant-border)] rounded-md px-5 py-4 shadow-sm">
-          <div className="text-sm text-[var(--color-text-primary)] leading-[1.75]">
+          <div className="text-[var(--color-text-primary)] leading-[1.75]">
             {message.content ? (
               <MarkdownRenderer content={message.content} />
             ) : isStreaming ? (

src/components/markdown/CodeBlock.tsx

@@ -1,7 +1,7 @@
 'use client';
 
 import { useEffect, useRef, useState, useMemo } from 'react';
-import { Copy, Check, Eye } from 'lucide-react';
+import { Copy, Check, Eye, ChevronDown, ChevronUp } from 'lucide-react';
 import { cn } from '@/lib/utils';
 import Prism from 'prismjs';
 import { HtmlPreviewModal } from '@/components/ui/HtmlPreviewModal';
@@ -30,6 +30,10 @@ interface CodeBlockProps {
   language?: string;
   showLineNumbers?: boolean;
   className?: string;
+  /** 折叠阈值，超过此行数自动折叠，默认 60 */
+  maxCollapsedLines?: number;
+  /** 折叠时预览的行数，默认 30 */
+  previewLines?: number;
 }
 
 // 语言别名映射
@@ -51,9 +55,12 @@ export function CodeBlock({
   language = 'text',
   showLineNumbers = true,
   className,
+  maxCollapsedLines = 60,
+  previewLines = 30,
 }: CodeBlockProps) {
   const [copied, setCopied] = useState(false);
   const [previewOpen, setPreviewOpen] = useState(false);
+  const [isExpanded, setIsExpanded] = useState(false);
 
   // 规范化语言名称
   const normalizedLanguage = languageAliases[language.toLowerCase()] || language.toLowerCase();
@@ -62,17 +69,33 @@ export function CodeBlock({
   const isHtmlPreviewable = ['html', 'htm', 'markup'].includes(normalizedLanguage) ||
                             ['html', 'htm'].includes(language.toLowerCase());
 
+  const lines = code.split('\n');
+  const totalLines = lines.length;
+  const shouldCollapse = totalLines > maxCollapsedLines;
+  const remainingLines = totalLines - previewLines;
+
+  // 根据折叠状态获取显示的代码
+  const displayCode = useMemo(() => {
+    if (shouldCollapse && !isExpanded) {
+      return lines.slice(0, previewLines).join('\n');
+    }
+    return code;
+  }, [code, lines, shouldCollapse, isExpanded, previewLines]);
+
+  const displayLines = displayCode.split('\n');
+
   // 使用 useMemo 缓存高亮后的 HTML，避免频繁重新高亮
   const highlightedCode = useMemo(() => {
     const grammar = Prism.languages[normalizedLanguage];
     if (grammar) {
-      return Prism.highlight(code, grammar, normalizedLanguage);
+      return Prism.highlight(displayCode, grammar, normalizedLanguage);
     }
-    return code;
+    return displayCode;
-  }, [code, normalizedLanguage]);
+  }, [displayCode, normalizedLanguage]);
 
   const handleCopy = async () => {
     try {
+      // 始终复制完整代码
       await navigator.clipboard.writeText(code);
       setCopied(true);
       setTimeout(() => setCopied(false), 2000);
@@ -81,13 +104,15 @@ export function CodeBlock({
     }
   };
 
-  const lines = code.split('\n');
+  const toggleExpand = () => {
+    setIsExpanded(!isExpanded);
+  };
 
   return (
     <div className={cn('relative group rounded overflow-hidden my-4', className)}
          style={{ boxShadow: 'var(--color-code-shadow)' }}>
       {/* 顶部工具栏 */}
-      <div className="flex items-center justify-between px-4 py-2.5 text-sm"
+      <div className="flex items-center justify-between px-4 py-2.5 text-[0.9em]"
            style={{
              backgroundColor: 'var(--color-code-toolbar-bg)',
              color: 'var(--color-code-toolbar-text)',
@@ -106,6 +131,12 @@ export function CodeBlock({
                   style={{ backgroundColor: '#27c93f', boxShadow: '0 0 0 1px rgba(0, 0, 0, 0.1) inset' }} />
           </div>
           <span className="font-mono text-[13px]">{language || 'code'}</span>
+          {/* 显示总行数 */}
+          {shouldCollapse && (
+            <span className="text-[12px] opacity-60">
+              ({totalLines} 行)
+            </span>
+          )}
         </div>
 
         {/* 右侧：操作按钮 */}
@@ -145,42 +176,95 @@ export function CodeBlock({
       </div>
 
       {/* 代码区域 */}
-      <div className="relative overflow-x-auto"
+      <div style={{ backgroundColor: 'var(--color-code-bg)' }}>
-           style={{ backgroundColor: 'var(--color-code-bg)' }}>
+        {/* 代码内容 - 使用 flex 布局 */}
+        <div className="flex overflow-x-auto">
+          {/* 行号列 */}
           {showLineNumbers && (
-          <div className="absolute left-0 top-0 bottom-0 w-12 select-none"
+            <div
+              className="flex-shrink-0 w-12 select-none py-4 px-2 text-right"
               style={{
                 backgroundColor: 'var(--color-code-bg)',
                 borderRight: '1px solid var(--color-code-line-border)'
-               }}>
+              }}
-            <div className="py-4 px-2 text-right">
+            >
-              {lines.map((_, index) => (
+              {displayLines.map((_, index) => (
                 <div
                   key={index}
-                  className="text-sm font-mono leading-6"
+                  className="font-mono leading-6"
                   style={{ color: 'var(--color-code-line-number)' }}
                 >
                   {index + 1}
                 </div>
               ))}
             </div>
-          </div>
           )}
+          {/* 代码列 */}
           <pre
-          className={cn(
+            className="flex-1 p-4 overflow-x-auto"
-            'p-4 overflow-x-auto',
-            showLineNumbers && 'pl-16'
-          )}
             style={{ margin: 0, background: 'transparent' }}
           >
             <code
-            className={`language-${normalizedLanguage} text-sm leading-6`}
+              className={`language-${normalizedLanguage} leading-6`}
               style={{ color: 'var(--color-code-text)' }}
               dangerouslySetInnerHTML={{ __html: highlightedCode }}
             />
           </pre>
         </div>
 
+        {/* 渐变遮罩和展开按钮（仅在折叠状态下显示） */}
+        {shouldCollapse && !isExpanded && (
+          <>
+            {/* 渐变遮罩 */}
+            <div
+              className="h-16 -mt-16 pointer-events-none relative z-10"
+              style={{
+                background: `linear-gradient(to bottom, transparent, var(--color-code-bg))`
+              }}
+            />
+            {/* 展开按钮 */}
+            <div
+              className="py-3 text-center cursor-pointer transition-colors hover:opacity-80"
+              style={{ backgroundColor: 'var(--color-code-bg)' }}
+              onClick={toggleExpand}
+            >
+              <button
+                className="inline-flex items-center gap-2 px-4 py-2 rounded-lg text-[0.9em] font-medium transition-colors"
+                style={{
+                  color: 'var(--color-primary)',
+                  backgroundColor: 'var(--color-primary-alpha)'
+                }}
+              >
+                <ChevronDown size={16} />
+                <span>展开剩余 {remainingLines} 行代码</span>
+              </button>
+            </div>
+          </>
+        )}
+
+        {/* 收起按钮（仅在展开状态下显示） */}
+        {shouldCollapse && isExpanded && (
+          <div
+            className="py-3 text-center cursor-pointer transition-colors"
+            style={{
+              backgroundColor: 'var(--color-code-bg)',
+              borderTop: '1px solid var(--color-code-line-border)'
+            }}
+            onClick={toggleExpand}
+          >
+            <button
+              className="inline-flex items-center gap-2 px-4 py-2 rounded-lg text-[0.9em] font-medium transition-colors"
+              style={{
+                color: 'var(--color-code-toolbar-text)'
+              }}
+            >
+              <ChevronUp size={16} />
+              <span>收起代码</span>
+            </button>
+          </div>
+        )}
+      </div>
+
       {/* HTML 预览模态框 */}
       {isHtmlPreviewable && (
         <HtmlPreviewModal

src/components/markdown/MarkdownRenderer.tsx

@@ -48,31 +48,31 @@ const markdownComponents = {
     );
   },
 
-  // 标题
+  // 标题 - 使用相对单位保持与全局字体的比例
   h1({ children }: { children?: React.ReactNode }) {
     return (
-      <h1 className="text-lg font-bold mt-5 mb-3 text-[var(--color-text-primary)]">
+      <h1 className="text-[1.25em] font-bold mt-5 mb-3 text-[var(--color-text-primary)]">
         {children}
       </h1>
     );
   },
   h2({ children }: { children?: React.ReactNode }) {
     return (
-      <h2 className="text-base font-bold mt-4 mb-2 text-[var(--color-text-primary)]">
+      <h2 className="text-[1.125em] font-bold mt-4 mb-2 text-[var(--color-text-primary)]">
         {children}
       </h2>
     );
   },
   h3({ children }: { children?: React.ReactNode }) {
     return (
-      <h3 className="text-sm font-semibold mt-3 mb-2 text-[var(--color-text-primary)]">
+      <h3 className="text-[1em] font-semibold mt-3 mb-2 text-[var(--color-text-primary)]">
         {children}
       </h3>
     );
   },
   h4({ children }: { children?: React.ReactNode }) {
     return (
-      <h4 className="text-sm font-semibold mt-2 mb-1 text-[var(--color-text-primary)]">
+      <h4 className="text-[1em] font-semibold mt-2 mb-1 text-[var(--color-text-primary)]">
         {children}
       </h4>
     );
@@ -95,7 +95,7 @@ const markdownComponents = {
   },
   li({ children }: { children?: React.ReactNode }) {
     return (
-      <li className="leading-relaxed text-sm">
+      <li className="leading-relaxed">
         {children}
       </li>
     );
@@ -136,7 +136,7 @@ const markdownComponents = {
   // 引用
   blockquote({ children }: { children?: React.ReactNode }) {
     return (
-      <blockquote className="border-l-3 border-[var(--color-primary)] pl-3 my-3 italic text-sm text-[var(--color-text-secondary)]">
+      <blockquote className="border-l-3 border-[var(--color-primary)] pl-3 my-3 italic text-[var(--color-text-secondary)]">
         {children}
       </blockquote>
     );
@@ -153,7 +153,7 @@ const markdownComponents = {
   table({ children }: { children?: React.ReactNode }) {
     return (
       <div className="overflow-x-auto my-3">
-        <table className="min-w-full border border-[var(--color-border)] rounded-lg overflow-hidden text-sm">
+        <table className="min-w-full border border-[var(--color-border)] rounded-lg overflow-hidden text-[0.9em]">
           {children}
         </table>
       </div>
@@ -182,14 +182,14 @@ const markdownComponents = {
   },
   th({ children }: { children?: React.ReactNode }) {
     return (
-      <th className="px-3 py-1.5 text-left text-xs font-semibold text-[var(--color-text-primary)]">
+      <th className="px-3 py-1.5 text-left text-[0.85em] font-semibold text-[var(--color-text-primary)]">
         {children}
       </th>
     );
   },
   td({ children }: { children?: React.ReactNode }) {
     return (
-      <td className="px-3 py-1.5 text-xs text-[var(--color-text-secondary)]">
+      <td className="px-3 py-1.5 text-[0.85em] text-[var(--color-text-secondary)]">
         {children}
       </td>
     );

src/components/ui/HtmlPreviewModal.tsx

@@ -1,6 +1,6 @@
 'use client';
 
-import { useState, useCallback, useEffect, useRef } from 'react';
+import { useState, useCallback, useEffect, useRef, useMemo } from 'react';
 import {
   X,
   Monitor,
@@ -83,6 +83,29 @@ export function HtmlPreviewModal({
   // 获取当前设备配置
   const currentDevice = deviceConfigs.find((d) => d.type === device) || deviceConfigs[0];
 
+  // 处理 HTML 代码，注入 <base target="_blank"> 防止链接影响父窗口
+  const processedHtmlCode = useMemo(() => {
+    const baseTag = '<base target="_blank">';
+
+    // 检查是否已经有 <base> 标签
+    if (/<base\s/i.test(htmlCode)) {
+      return htmlCode;
+    }
+
+    // 尝试在 <head> 标签后注入
+    if (/<head[^>]*>/i.test(htmlCode)) {
+      return htmlCode.replace(/<head[^>]*>/i, `$&\n    ${baseTag}`);
+    }
+
+    // 尝试在 <html> 标签后注入
+    if (/<html[^>]*>/i.test(htmlCode)) {
+      return htmlCode.replace(/<html[^>]*>/i, `$&\n  <head>\n    ${baseTag}\n  </head>`);
+    }
+
+    // 如果都没有，在最前面添加
+    return `<head>${baseTag}</head>\n${htmlCode}`;
+  }, [htmlCode]);
+
   // ESC 关闭 / F11 全屏切换
   useEffect(() => {
     if (!isOpen) return;
@@ -348,7 +371,7 @@ export function HtmlPreviewModal({
                 {/* iframe 预览 */}
                 <iframe
                   key={iframeKey}
-                  srcDoc={htmlCode}
+                  srcDoc={processedHtmlCode}
                   sandbox="allow-scripts allow-same-origin"
                   className="w-full bg-white"
                   style={{