# 实现方案

## 修改文件
- `src/pages/ReportEditor.tsx`

## 修改 1：`confirmAiInjection` 保留撤销栈（约 line 981-998）

**原代码**：
```tsx
  const confirmAiInjection = (newHtml: string, regionId: string) => {
    if (!editorRef.current) return;
    const targetContent = editorRef.current.querySelector(`.ai-region[data-ai-id="${regionId}"] .ai-content`) as HTMLElement;
    if (targetContent) {
      targetContent.innerHTML = newHtml;
      targetContent.style.transition = 'background-color 0.3s ease';
      targetContent.style.backgroundColor = '#bfdbfe';
      setTimeout(() => {
        targetContent.style.backgroundColor = '#eff6ff';
        setTimeout(() => {
          targetContent.style.backgroundColor = 'transparent';
        }, 800);
      }, 400);
      contentRef.current = editorRef.current.innerHTML;
      saveDraftToStorage();
    }
    setDiffModal(null);
  };
```

**新代码**：
```tsx
  const confirmAiInjection = (newHtml: string, regionId: string) => {
    if (!editorRef.current) return;
    const targetContent = editorRef.current.querySelector(`.ai-region[data-ai-id="${regionId}"] .ai-content`) as HTMLElement;
    if (targetContent) {
      targetContent.focus();
      const sel = window.getSelection();
      const range = document.createRange();
      range.selectNodeContents(targetContent);
      sel?.removeAllRanges();
      sel?.addRange(range);
      document.execCommand('insertHTML', false, newHtml);
      targetContent.style.transition = 'background-color 0.3s ease';
      targetContent.style.backgroundColor = '#bfdbfe';
      setTimeout(() => {
        targetContent.style.backgroundColor = '#eff6ff';
        setTimeout(() => {
          targetContent.style.backgroundColor = 'transparent';
        }, 800);
      }, 400);
      contentRef.current = editorRef.current.innerHTML;
      saveDraftToStorage();
    }
    setDiffModal(null);
  };
```

**变更点**：
1. 去掉 `targetContent.innerHTML = newHtml;`
2. 增加 `targetContent.focus()`
3. 使用 `Range.selectNodeContents(targetContent)` 选中区域内所有旧内容
4. 使用 `document.execCommand('insertHTML', false, newHtml)` 执行替换
5. 浏览器撤销栈会记录这次替换，Ctrl+Z 可正常撤销

## 修改 2：`handleAIGenerate` 中 `<p>` 标签注入样式（约 line 955-970）

**原代码**：
```tsx
      if (responseJson.updatedHtml && aiModifyEnabled) {
        let cleanHtml = responseJson.updatedHtml;
        cleanHtml = cleanHtml.replace(/<br\s*\/?>/gi, '');
        cleanHtml = cleanHtml.replace(/<\/p>\s*<p>/gi, '</p><p>');
        cleanHtml = cleanHtml.trim();
        if (targetRegionEl) {
```

**新代码**：
```tsx
      if (responseJson.updatedHtml && aiModifyEnabled) {
        let cleanHtml = responseJson.updatedHtml;
        cleanHtml = cleanHtml.replace(/<br\s*\/?>/gi, '');
        cleanHtml = cleanHtml.replace(/<\/p>\s*<p>/gi, '</p><p>');
        cleanHtml = cleanHtml.trim();
        cleanHtml = cleanHtml.replace(/<p>/gi, '<p style="padding: 0px; font-family: SimSun; font-size: 12pt; line-height: 1.5;">');
        if (targetRegionEl) {
```

**变更点**：在 `cleanHtml.trim()` 后增加一行正则替换，将所有 `<p>` 标签替换为带标准内联样式的 `<p>` 标签。

**样式值说明**：
- `padding: 0px`：与原始段落一致
- `font-family: SimSun`：宋体
- `font-size: 12pt`：12pt 字号
- `line-height: 1.5`：1.5 倍行高