// ======= 工具：创建编辑按钮（含铅笔 SVG） =======
  function createEditButton(onClick) {
    const btn = document.createElement('button');
    btn.type = 'button';
    btn.className = 'edit-btn';
    btn.setAttribute('aria-label', '编辑标题');
    btn.innerHTML = `
      <svg viewBox="0 0 24 24" aria-hidden="true">
        <i class="fas fa-pencil-alt"></i>
      </svg>
    `;
    btn.addEventListener('click', (e) => {
      e.stopPropagation();
      onClick && onClick();
    });
    return btn;
  }
// ======= 模态框：打开标题编辑器 =======
  function openTitleEditor({ title = '修改标题', initialValue = '', onSubmit }) {
    const backdrop = document.createElement('div');
    backdrop.className = 'title_change_modal-backdrop';

    const title_change_modal = document.createElement('div');
    title_change_modal.className = 'title_change_modal';
    title_change_modal.setAttribute('role', 'dialog');
    title_change_modal.setAttribute('aria-title_change_modal', 'true');

    title_change_modal.innerHTML = `
      <h3 id="dialog-title">${title}</h3>
      <div class="field">
        <label for="title-input" class="sr-only">标题</label>
        <input id="title-input" type="text" placeholder="请输入标题" value="${escapeHtmlAttr(initialValue)}" />
        <div class="error" id="title-error"></div>
      </div>
      <div class="actions">
        <button type="button" class="btn" id="cancel-btn">取消</button>
        <button type="button" class="btn primary" id="ok-btn">确定</button>
      </div>
    `;
    backdrop.appendChild(title_change_modal);
    document.body.appendChild(backdrop);

    const input = title_change_modal.querySelector('#title-input');
    const okBtn  = title_change_modal.querySelector('#ok-btn');
    const cancelBtn = title_change_modal.querySelector('#cancel-btn');
    const errBox = title_change_modal.querySelector('#title-error');
    const prevFocus = document.activeElement;

    const close = () => {
      document.body.removeChild(backdrop);
      if (prevFocus && prevFocus.focus) prevFocus.focus();
    };

    const submit = () => {
      const raw = input.value;
      const result = onSubmit ? onSubmit(raw) : { ok: true };
      if (result && result.ok) {
        close();
      } else if (result && result.message) {
        errBox.textContent = result.message;
        input.setAttribute('aria-invalid', 'true');
        input.focus();
      }
    };

    okBtn.addEventListener('click', submit);
    cancelBtn.addEventListener('click', close);
    backdrop.addEventListener('click', (e) => {
      if (e.target === backdrop) close(); // 点击遮罩关闭
    });
    title_change_modal.addEventListener('keydown', (e) => {
      if (e.key === 'Escape') close();
      if (e.key === 'Enter') submit();
    });

    // 初始聚焦
    setTimeout(() => input.focus(), 0);
  }

  // ======= 验证与规范化 =======
  function validateTitle(raw) {
    if (typeof raw !== 'string') return { ok: false, message: '标题格式不正确' };

    // 1) 去掉 Markdown 井号前缀（若用户手动输入了 ### ）
    let t = raw.replace(/^#+\s*/, '');

    // 2) 替换换行为单空格（标题单行）
    t = t.replace(/\r?\n+/g, ' ');

    // 3) 去首尾空白 & 折叠多空格
    t = t.trim().replace(/\s{2,}/g, ' ');

    // 4) 基础规则
    if (t.length === 0) return { ok: false, message: '标题不能为空' };
    if (t.length > 80)  return { ok: false, message: '标题不能超过 80 个字符' };

    // 5) 可选：禁止只包含标点
    if (!/[0-9A-Za-z\u4e00-\u9fa5]/.test(t)) {
      return { ok: false, message: '标题需包含字母/数字/中文' };
    }

    return { ok: true, value: t };
  }

  // 显示时的规范化（比如初始渲染）
  function normalizeTitle(s) {
    if (!s) return '';
    return s.replace(/^#+\s*/, '').replace(/\r?\n+/g, ' ').trim().replace(/\s{2,}/g, ' ');
  }

  // 简单转义，避免把初始值插进 input 时破坏属性
  function escapeHtmlAttr(s) {
    return String(s).replace(/&/g,'&amp;').replace(/"/g,'&quot;').replace(/</g,'&lt;').replace(/>/g,'&gt;');
  }