/* ===== 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;
      
      --font-base: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
      --font-mono: "SF Mono", "Cascadia Code", Consolas, monospace;
    }

    *, *::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-block { width: 100%; }

    /* ===== 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 (Guide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: 2.5rem; font-weight: 800; margin-bottom: 24px; letter-spacing: -0.5px; position: relative; z-index: 1; }
    .quick-answer { background: rgba(255,255,255,0.05); border: 1px solid rgba(255,255,255,0.15); padding: 24px 32px; border-radius: var(--radius-lg); font-size: 1.1rem; line-height: 1.8; margin: 0 auto 30px; max-width: 800px; color: rgba(255,255,255,0.9); font-style: italic; backdrop-filter: blur(5px); position: relative; z-index: 1; }

    /* 数据统计条 */
    .stats-row { display: flex; justify-content: center; gap: 40px; flex-wrap: wrap; margin-top: 20px; }
    .stat-item { text-align: center; }
    .stat-number { font-size: 1.8rem; font-weight: 800; color: var(--accent); }
    .stat-label { font-size: 0.85rem; color: rgba(255,255,255,0.6); margin-top: 4px; text-transform: uppercase; }

    /* ===== 沉浸式宽列容器 ===== */
    .reading-container { max-width: 900px; margin: 40px auto 80px; padding: 0 24px; position: relative; z-index: 10; }

    /* ===== 内联前置导航 (Bento TOC) ===== */
    .bento-toc { display: grid; grid-template-columns: 2fr 1fr; gap: 20px; margin-bottom: 60px; }
    .toc-card { background: var(--bg-card); border-radius: var(--radius-xl); padding: 30px; box-shadow: var(--shadow-card); border: 1px solid var(--border-light); }
    .toc-card h3 { font-size: 1.2rem; color: var(--bg-header); margin-bottom: 16px; font-weight: 800; display: flex; align-items: center; gap: 8px; }
    .toc-card h3::before { content: ''; width: 4px; height: 18px; background: var(--accent); border-radius: 4px; }
    .toc-links { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; list-style: none; padding: 0; }
    .toc-links a { color: var(--text-secondary); font-weight: 600; font-size: 0.95rem; display: block; padding: 8px 12px; background: var(--bg-secondary); border-radius: var(--radius-sm); transition: 0.3s; }
    .toc-links a:hover { background: var(--accent-light); color: var(--bg-header); transform: translateX(4px); }
    
    /* 快捷入口区块 */
    .quick-card { background: linear-gradient(135deg, var(--bg-header) 0%, #25160a 100%); color: var(--text-white); border-color: var(--bg-header); }
    .quick-card h3 { color: var(--accent); }
    .quick-card h3::before { display: none; }
    .quick-list { list-style: none; padding: 0; display: flex; flex-direction: column; gap: 10px; }
    .quick-list a { color: rgba(255,255,255,0.8); font-size: 0.95rem; font-weight: 500; display: flex; justify-content: space-between; border-bottom: 1px solid rgba(255,255,255,0.1); padding-bottom: 8px; }
    .quick-list a:hover { color: var(--accent); border-color: var(--accent); }

    /* ===== 正文区块 ===== */
    .main-section { background: var(--bg-card); border-radius: var(--radius-xl); padding: 45px; box-shadow: var(--shadow-card); border: 1px solid var(--border-light); margin-bottom: 40px; }
    .main-section h2 { font-size: 1.8rem; color: var(--bg-header); margin-bottom: 24px; padding-bottom: 16px; border-bottom: 3px solid var(--bg-primary); }
    .main-section h3 { font-size: 1.3rem; margin: 32px 0 16px; color: var(--bg-header); }
    .main-section p { margin-bottom: 20px; font-size: 1.05rem; }

    /* ===== 提示框系统 ===== */
    .alert { padding: 20px; border-radius: var(--radius-lg); margin: 24px 0; font-size: 0.95rem; display: flex; gap: 16px; align-items: flex-start; }
    .alert-icon { font-size: 1.4rem; line-height: 1; }
    .alert.info { background: var(--bg-secondary); border-left: 4px solid var(--bg-header); color: var(--text-secondary); }
    .alert.warning { background: #fef8eb; border-left: 4px solid var(--accent); color: #926400; }
    .alert.success { background: #f0fdf4; border-left: 4px solid #16a34a; color: #14532d; }

    /* ===== 品牌历史时间轴 (Grid版) ===== */
    .history-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; margin: 24px 0; }
    .history-card { background: var(--bg-secondary); border: 1px solid var(--border-light); padding: 24px; border-radius: var(--radius-lg); position: relative; overflow: hidden; }
    .history-card::before { content: ''; position: absolute; left: 0; top: 0; bottom: 0; width: 4px; background: var(--accent-light); }
    .history-card:hover::before { background: var(--accent); }
    .history-date { font-weight: 800; color: var(--bg-header); font-size: 1.2rem; margin-bottom: 8px; display: flex; align-items: center; gap: 8px; }
    .history-desc { font-size: 0.95rem; margin: 0; }

    /* ===== 套餐卡片 ===== */
    .plan-cards { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; margin: 24px 0; }
    .plan-card { border: 1px solid var(--border-light); border-radius: var(--radius-lg); padding: 24px; text-align: center; transition: 0.3s; background: var(--bg-card); }
    .plan-card:hover { border-color: var(--accent); box-shadow: var(--shadow-soft); transform: translateY(-4px); }
    .plan-card.hot { border: 2px solid var(--accent); }
    .card-badge { display: inline-block; padding: 4px 12px; border-radius: 20px; font-size: 0.8rem; font-weight: 700; margin-bottom: 16px; }
    .badge-hot { background: var(--accent-light); color: var(--bg-header); }
    .badge-cheap { background: var(--bg-secondary); color: var(--text-muted); }
    .badge-limited { background: rgba(37, 22, 10, 0.1); color: var(--bg-header); }
    .plan-price { font-size: 1.8rem; font-weight: 800; color: var(--bg-header); margin: 8px 0 16px; }
    .plan-price span { font-size: 0.9rem; color: var(--text-muted); }
    .plan-specs { list-style: none; padding: 0; margin-bottom: 24px; text-align: left; }
    .plan-specs li { font-size: 0.95rem; color: var(--text-secondary); padding: 8px 0; border-bottom: 1px dashed var(--border-light); display: flex; justify-content: space-between; }
    .plan-specs li:last-child { border-bottom: none; }

    /* ===== 优势网格 ===== */
    .adv-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; margin: 24px 0; }
    .adv-item { display: flex; gap: 16px; align-items: flex-start; }
    .adv-icon { font-size: 1.8rem; flex-shrink: 0; }
    .adv-item h4 { margin: 0 0 8px; font-size: 1.1rem; color: var(--bg-header); }
    .adv-item p { font-size: 0.95rem; margin: 0; line-height: 1.6; }

    /* ===== 适合人群卡片 ===== */
    .usecase-cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; margin: 24px 0; }
    .u-card { background: var(--bg-secondary); padding: 24px; border-radius: var(--radius-lg); text-align: center; border: 1px solid var(--border-light); }
    .u-icon { font-size: 2rem; margin-bottom: 16px; }
    .u-card h4 { font-size: 1.1rem; margin-bottom: 8px; color: var(--bg-header); }
    .u-card p { font-size: 0.9rem; margin-bottom: 16px; }
    .u-pick { font-weight: 800; color: var(--accent); font-size: 0.9rem; }

    /* ===== 现代表格 ===== */
    .table-wrapper { overflow-x: auto; margin: 24px 0; border-radius: var(--radius-lg); border: 1px solid var(--border-light); }
    .modern-table { width: 100%; border-collapse: separate; border-spacing: 0; min-width: 600px; text-align: left; background: var(--bg-card); }
    .modern-table th { background: var(--bg-secondary); padding: 16px 20px; font-weight: 700; font-size: 0.95rem; color: var(--bg-header); border-bottom: 1px solid var(--border-light); }
    .modern-table td { padding: 16px 20px; border-bottom: 1px solid var(--border-light); font-size: 0.95rem; }
    .modern-table tr:last-child td { border-bottom: none; }
    .modern-table .highlight-col { font-weight: 700; color: var(--bg-header); background: var(--accent-light); }

    /* ===== FAQ 手风琴 ===== */
    .faq-list { display: flex; flex-direction: column; gap: 12px; margin-top: 24px; }
    .faq-item { border: 1px solid var(--border-light); border-radius: var(--radius-sm); overflow: hidden; background: var(--bg-secondary); transition: 0.3s; }
    .faq-q { padding: 16px 20px; font-weight: 700; cursor: pointer; display: flex; justify-content: space-between; align-items: center; color: var(--text-main); }
    .faq-q::after { content: '+'; font-size: 1.5rem; color: var(--text-muted); transition: 0.3s; }
    .faq-item.open { border-color: var(--accent); background: var(--bg-card); box-shadow: var(--shadow-soft); }
    .faq-item.open .faq-q { color: var(--accent); }
    .faq-item.open .faq-q::after { transform: rotate(45deg); color: var(--accent); }
    .faq-a { max-height: 0; overflow: hidden; padding: 0 20px; color: var(--text-muted); transition: max-height 0.3s ease-out; line-height: 1.8;}
    .faq-item.open .faq-a { max-height: 400px; padding: 0 20px 20px; }

    /* ===== CTA 盒子 ===== */
    .cta-box { background: var(--bg-secondary); border: 1px solid var(--border-light); border-radius: var(--radius-lg); padding: 40px; text-align: center; margin: 40px 0; }
    .cta-box h3 { margin-top: 0; color: var(--bg-header); font-size: 1.4rem; margin-bottom: 12px; }
    .cta-box p { margin-bottom: 24px; color: var(--text-muted); }
    .btn-group { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

    /* ===== Footer (统一) ===== */
    .footer { background: var(--bg-footer); color: rgba(255,255,255,0.6); padding: 80px 0 30px; margin-top: 60px; }
    .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) {
      .bento-toc { grid-template-columns: 1fr; }
      .usecase-cards { 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 80px; }
      .hero h1 { font-size: 2.2rem; }
      .reading-container { margin-top: -40px; }
      .main-section { padding: 30px 20px; }
      
      .toc-links, .history-grid, .plan-cards, .adv-grid, .usecase-cards { grid-template-columns: 1fr; }
      .modern-table { display: block; overflow-x: auto; white-space: nowrap; }
      .footer-grid { grid-template-columns: 1fr; gap: 40px; }
    }