/* ===== 核心品牌色彩系统 (绝对统一) ===== */
    :root {
      --bg-primary: #e4e0dc;
      --bg-secondary: #f2f0ed;
      --bg-card: #ffffff;
      --bg-header: #3f2814;
      --bg-footer: #25160a;
      
      --accent: #dc9700;
      --accent-hover: #f0a800;
      --accent-gradient: linear-gradient(135deg, #fed107, #dd9800);
      --accent-light: rgba(220, 151, 0, 0.1);
      
      --text-main: #111827;
      --text-secondary: #374151;
      --text-muted: #6b7280;
      --text-white: #ffffff;

      --border: #d1d5db;
      --border-light: #e5e7eb;
      
      --shadow-soft: 0 4px 20px rgba(0,0,0,0.05);
      --shadow-card: 0 10px 30px rgba(63,40,20,0.08);
      --shadow-hover: 0 15px 35px rgba(63,40,20,0.15);
      
      --radius-xl: 20px;
      --radius-lg: 12px;
      --radius-sm: 6px;
      
      --max-width: 1200px;
      --font-base: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
    }

    *, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
    html { scroll-behavior: smooth; font-size: 16px; }
    body { font-family: var(--font-base); background: var(--bg-primary); color: var(--text-secondary); line-height: 1.7; -webkit-font-smoothing: antialiased; }
    a { color: var(--accent); text-decoration: none; transition: 0.3s; }
    a:hover { color: var(--bg-header); }
    ul, ol { list-style-position: inside; }

    /* ===== 按钮系统 ===== */
    .btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 12px 28px; border-radius: var(--radius-sm); font-weight: 700; cursor: pointer; transition: 0.3s; border: none; font-size: 1rem; text-align: center;}
    .btn-primary { background: var(--accent-gradient); color: var(--bg-header); box-shadow: 0 4px 10px rgba(220,151,0,0.3); }
    .btn-primary:hover { transform: translateY(-2px); box-shadow: 0 6px 15px rgba(220,151,0,0.4); color: var(--bg-header); }
    .btn-outline { background: transparent; color: var(--bg-header); border: 2px solid var(--bg-header); }
    .btn-outline:hover { background: var(--bg-header); color: var(--text-white); }
    .btn-large { padding: 16px 36px; font-size: 1.1rem; border-radius: 50px; }
    .btn-green { background: #16a34a; color: white; }
    .btn-green:hover { background: #15803d; color: white; transform: translateY(-2px); }

    /* ===== 统一导航 & 进度条 ===== */
    .nav { position: sticky; top: 0; background: var(--bg-header); border-bottom: 2px solid var(--accent); z-index: 1000; box-shadow: 0 2px 10px rgba(0,0,0,0.1); }
    .nav-container { max-width: 1200px; margin: 0 auto; padding: 0 24px; display: flex; align-items: center; justify-content: space-between; height: 70px; }
    .nav-logo { font-size: 1.5rem; font-weight: 800; color: var(--accent); }
    .nav-logo span { color: var(--text-white); }
    .nav-links { display: flex; gap: 24px; align-items: center; list-style: none; }
    .nav-links a { color: rgba(255,255,255,0.85); font-weight: 600; font-size: 0.95rem; }
    .nav-links a:hover, .nav-links a.active { color: var(--accent); }
    .nav-toggle { display: none; background: transparent; border: none; color: white; font-size: 1.5rem; cursor: pointer;}
    
    #progress-container { position: sticky; top: 70px; left: 0; width: 100%; background: transparent; z-index: 999; }
    #progress-bar { height: 100%; width: 0%; background: var(--accent-gradient); }

    /* ===== Hero 首屏 (FAQ专属) ===== */
    .hero { background: var(--bg-header); color: var(--text-white); padding: 80px 24px; text-align: center; position: relative; overflow: hidden; }
    .hero::before { content: ''; position: absolute; left: 50%; top: -50px; transform: translateX(-50%); width: 800px; height: 300px; background: radial-gradient(ellipse, rgba(220,151,0,0.15) 0%, transparent 70%); pointer-events: none; }
    .hero h1 { font-size: 2.8rem; font-weight: 800; margin-bottom: 16px; letter-spacing: -0.5px; position: relative; z-index: 1; }
    .hero p { font-size: 1.15rem; color: rgba(255,255,255,0.8); max-width: 600px; margin: 0 auto; position: relative; z-index: 1; }

    /* ===== 页面主架构 (带左侧粘性索引) ===== */
    .faq-layout { max-width: 1200px; margin: 40px auto 80px; padding: 0 24px; display: grid; grid-template-columns: 280px 1fr; gap: 60px; align-items: start; }

    /* 左侧粘性索引 */
    .sidebar-nav { position: sticky; top: 100px; background: var(--bg-card); border-radius: var(--radius-xl); padding: 30px; box-shadow: var(--shadow-card); border: 1px solid var(--border-light); }
    .sidebar-nav h4 { font-size: 1.1rem; color: var(--bg-header); margin-bottom: 20px; font-weight: 800; display: flex; align-items: center; gap: 8px; }
    .sidebar-nav h4::before { content: ''; width: 4px; height: 18px; background: var(--accent); border-radius: 4px; }
    .index-list { list-style: none; padding: 0; display: flex; flex-direction: column; gap: 12px; }
    .index-list a { color: var(--text-secondary); font-weight: 600; font-size: 0.95rem; display: flex; align-items: center; gap: 10px; padding: 10px 16px; border-radius: var(--radius-sm); transition: 0.3s; }
    .index-list a:hover { background: var(--bg-secondary); color: var(--bg-header); }
    .index-list a.active { background: var(--accent-light); color: var(--bg-header); border-left: 3px solid var(--accent); }
    .index-badge { background: var(--bg-primary); color: var(--text-muted); font-size: 0.75rem; padding: 2px 8px; border-radius: 12px; margin-left: auto; }

    /* ===== 右侧 FAQ 手风琴列表 ===== */
    .faq-group { margin-bottom: 50px; scroll-margin-top: 100px; }
    .faq-group-title { font-size: 1.8rem; color: var(--bg-header); margin-bottom: 12px; padding-bottom: 12px; border-bottom: 3px solid var(--bg-primary); }
    .faq-group-desc { color: var(--text-muted); margin-bottom: 24px; font-size: 0.95rem; }

    .faq-list { display: flex; flex-direction: column; gap: 16px; }
    .faq-item { background: var(--bg-card); border: 1px solid var(--border-light); border-radius: var(--radius-lg); overflow: hidden; transition: 0.3s; box-shadow: var(--shadow-soft); }
    .faq-item:hover { border-color: var(--accent); }
    
    .faq-q { padding: 24px; font-weight: 700; font-size: 1.05rem; cursor: pointer; display: flex; justify-content: space-between; align-items: center; color: var(--text-main); }
    .faq-q-content { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
    .faq-q::after { content: '+'; font-size: 1.8rem; color: var(--text-muted); transition: 0.3s; font-weight: 300; }
    
    .faq-item.open { border-color: var(--accent); box-shadow: var(--shadow-card); }
    .faq-item.open .faq-q { color: var(--bg-header); background: var(--accent-light); }
    .faq-item.open .faq-q::after { transform: rotate(45deg); color: var(--accent); }
    
    .faq-a { max-height: 0; overflow: hidden; padding: 0 24px; color: var(--text-secondary); transition: max-height 0.4s ease; line-height: 1.8; }
    .faq-item.open .faq-a { max-height: 800px; padding: 20px 24px 24px; }
    
    /* 答案内部元素格式化 */
    .faq-a ul, .faq-a ol { padding-left: 20px; margin: 12px 0; }
    .faq-a li { margin-bottom: 8px; }
    .faq-a strong { color: var(--bg-header); }

    /* 问题分类徽章 */
    .q-badge { font-size: 0.75rem; padding: 4px 10px; border-radius: 4px; font-weight: 600; white-space: nowrap; }
    .q-badge.tutorial { background: #f0fdf4; color: #16a34a; border: 1px solid #bbf7d0; }
    .q-badge.policy { background: #eff6ff; color: #2563eb; border: 1px solid #bfdbfe; }
    .q-badge.tech { background: #fdf4ff; color: #c026d3; border: 1px solid #f5d0fe; }

    /* ===== CTA 盒子 ===== */
    .cta-box { background: linear-gradient(135deg, var(--bg-header) 0%, #25160a 100%); color: var(--text-white); border-radius: var(--radius-xl); padding: 40px; text-align: center; margin: 40px 0; box-shadow: var(--shadow-card); }
    .cta-box h3 { margin-top: 0; color: var(--accent); font-size: 1.6rem; margin-bottom: 12px; }
    .cta-box p { margin-bottom: 24px; color: rgba(255,255,255,0.8); }

    /* ===== 相关文章网格 (Bento) ===== */
    .article-section { max-width: 1200px; margin: 0 auto 80px; padding: 0 24px; }
    .article-section h2 { text-align: center; font-size: 2rem; color: var(--bg-header); margin-bottom: 40px; }
    .article-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
    .article-card { background: var(--bg-card); border-radius: var(--radius-lg); padding: 30px; border: 1px solid var(--border-light); transition: 0.3s; display: block; position: relative; box-shadow: var(--shadow-soft); }
    .article-card:hover { transform: translateY(-5px); border-color: var(--accent); box-shadow: var(--shadow-hover); }
    .article-card h3 { font-size: 1.2rem; color: var(--text-main); margin: 16px 0 12px; }
    .article-card p { font-size: 0.95rem; color: var(--text-muted); margin: 0; }
    .article-tag { position: absolute; top: 20px; right: 20px; font-size: 0.75rem; font-weight: 800; padding: 4px 12px; border-radius: 20px; }
    .tag-guide { background: var(--bg-secondary); color: var(--bg-header); }

    /* ===== Footer (统一) ===== */
    .footer { background: var(--bg-footer); color: rgba(255,255,255,0.6); padding: 80px 0 30px; }
    .footer-grid { max-width: 1200px; margin: 0 auto; display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 60px; padding: 0 24px; margin-bottom: 60px; }
    .footer-col h4 { color: var(--text-white); font-size: 1.1rem; margin-bottom: 24px; font-weight: 700; }
    .footer-col p { line-height: 1.8; font-size: 0.95rem; }
    .footer-col ul { list-style: none; padding: 0; }
    .footer-col li { margin-bottom: 12px; }
    .footer-col a { color: rgba(255,255,255,0.6); font-size: 0.95rem; transition: 0.3s; }
    .footer-col a:hover { color: var(--accent); }
    .footer-bottom { border-top: 1px solid rgba(255,255,255,0.05); padding-top: 30px; text-align: center; font-size: 0.85rem; }

    /* ===== 响应式 ===== */
    @media (max-width: 1024px) {
      .faq-layout { grid-template-columns: 1fr; gap: 40px; }
      .sidebar-nav { position: static; display: flex; overflow-x: auto; padding: 15px; border-radius: var(--radius-lg); white-space: nowrap; }
      .sidebar-nav h4 { display: none; }
      .index-list { flex-direction: row; margin: 0; }
      .index-list a { padding: 8px 16px; }
      .index-badge { display: none; }
      .article-grid { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .nav-toggle { display: block; }
      .nav-links.open { display: flex; flex-direction: column; position: absolute; top: 70px; left: 0; right: 0; background: var(--bg-header); padding: 20px; border-top: 1px solid rgba(255,255,255,0.1); }
      
      .hero { padding: 60px 24px; }
      .hero h1 { font-size: 2.2rem; }
      
      .faq-q-content { flex-direction: column; align-items: flex-start; gap: 8px; }
      .article-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; gap: 40px; }
      .cta-box .btn { width: 100%; margin-bottom: 10px; }
    }