/* roulang page: index */
:root {
      --brand-burgundy: #7A1A2B;
      --brand-burgundy-dark: #5C0F1A;
      --accent-sky: #7FB3D8;
      --accent-sky-light: #A3CDE0;
      --gold: #C8A96E;
      --gold-hover: #D4BA85;
      --warm-white: #F7F4F2;
      --charcoal: #1E1D1B;
      --charcoal-light: #2A2927;
      --text-primary: #1A1917;
      --text-secondary: #4A4845;
      --text-on-dark: #E8E6E1;
      --text-muted: #6B6966;
      --border-light: #E0DBD5;
      --border-soft: #D1CCC5;
      --radius-card: 12px;
      --radius-btn: 6px;
      --shadow-card: 0 4px 20px rgba(0,0,0,0.06);
      --shadow-hover: 0 8px 30px rgba(0,0,0,0.12);
      --font-heading: 'Inter', 'Noto Sans SC', 'Source Han Sans CN', system-ui, -apple-system, sans-serif;
      --font-body: 'Inter', 'Noto Serif SC', 'Source Han Serif CN', Georgia, 'Times New Roman', serif;
      --transition-smooth: all 0.25s ease;
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: var(--font-body);
      background-color: var(--warm-white);
      color: var(--text-primary);
      line-height: 1.7;
      display: flex;
      min-height: 100vh;
      overflow-x: hidden;
    }
    /* 左侧导航 App Shell */
    .app-sidebar {
      width: 240px;
      background-color: var(--charcoal);
      color: var(--text-on-dark);
      display: flex;
      flex-direction: column;
      position: fixed;
      top: 0;
      left: 0;
      height: 100vh;
      z-index: 40;
      box-shadow: 2px 0 15px rgba(0,0,0,0.2);
      transition: transform 0.3s ease;
    }
    .sidebar-brand {
      padding: 2rem 1.5rem 1.5rem;
      border-bottom: 1px solid rgba(255,255,255,0.1);
      display: flex;
      align-items: center;
      gap: 0.75rem;
    }
    .brand-icon {
      background: linear-gradient(135deg, var(--brand-burgundy) 0%, #5a0e1e 100%);
      width: 40px;
      height: 40px;
      border-radius: 10px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 1.5rem;
      color: white;
      box-shadow: 0 4px 10px rgba(122,26,43,0.4);
    }
    .brand-text {
      font-family: var(--font-heading);
      font-weight: 700;
      font-size: 1.1rem;
      letter-spacing: 0.5px;
      color: white;
      line-height: 1.3;
    }
    .brand-text small {
      display: block;
      font-size: 0.7rem;
      font-weight: 400;
      color: var(--accent-sky-light);
      letter-spacing: 1px;
    }
    .sidebar-nav {
      flex: 1;
      padding: 2rem 1rem;
      display: flex;
      flex-direction: column;
      gap: 0.5rem;
    }
    .nav-item {
      color: #b0ada7;
      padding: 0.8rem 1.2rem;
      border-radius: 8px;
      font-family: var(--font-heading);
      font-weight: 500;
      font-size: 0.95rem;
      display: flex;
      align-items: center;
      gap: 0.8rem;
      transition: var(--transition-smooth);
      text-decoration: none;
      border-left: 3px solid transparent;
    }
    .nav-item i {
      width: 20px;
      text-align: center;
      font-size: 1.1rem;
    }
    .nav-item:hover {
      background-color: rgba(255,255,255,0.08);
      color: #f0ede7;
      border-left-color: var(--accent-sky);
    }
    .nav-item.active {
      background-color: rgba(255,255,255,0.12);
      color: white;
      font-weight: 600;
      border-left-color: var(--accent-sky);
    }
    .sidebar-footer {
      padding: 1.5rem;
      font-size: 0.75rem;
      color: #8a8882;
      border-top: 1px solid rgba(255,255,255,0.1);
    }
    /* 主内容区 */
    .main-content {
      margin-left: 240px;
      flex: 1;
      width: calc(100% - 240px);
      background-color: var(--warm-white);
    }
    /* 移动端导航 */
    .mobile-header {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 56px;
      background-color: var(--charcoal);
      z-index: 45;
      align-items: center;
      padding: 0 1rem;
      box-shadow: 0 2px 12px rgba(0,0,0,0.3);
    }
    .hamburger {
      font-size: 1.6rem;
      color: white;
      background: transparent;
      border: none;
      margin-right: 1rem;
    }
    .mobile-brand {
      font-family: var(--font-heading);
      font-weight: 700;
      color: white;
      font-size: 1rem;
    }
    .drawer-overlay {
      display: none;
      position: fixed;
      inset: 0;
      background: rgba(0,0,0,0.6);
      z-index: 44;
    }
    /* 容器与排版 */
    .container-custom {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 2rem;
    }
    section {
      padding: 5rem 0;
      scroll-margin-top: 20px;
    }
    .section-margin {
      margin-bottom: 1.5rem;
    }
    h1, h2, h3 {
      font-family: var(--font-heading);
      font-weight: 700;
      letter-spacing: -0.3px;
    }
    h2 {
      font-size: 2.4rem;
      margin-bottom: 2rem;
      color: var(--charcoal);
      position: relative;
      display: inline-block;
    }
    h2::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: -8px;
      width: 60px;
      height: 4px;
      background: var(--brand-burgundy);
      border-radius: 2px;
    }
    .btn-primary {
      background-color: var(--brand-burgundy);
      color: white;
      font-family: var(--font-heading);
      font-weight: 600;
      padding: 0.85rem 2rem;
      border-radius: var(--radius-btn);
      border: none;
      transition: var(--transition-smooth);
      display: inline-flex;
      align-items: center;
      gap: 0.5rem;
      box-shadow: 0 4px 12px rgba(122,26,43,0.3);
    }
    .btn-primary:hover {
      background-color: var(--brand-burgundy-dark);
      box-shadow: 0 8px 18px rgba(122,26,43,0.4);
      transform: translateY(-1px);
      color: white;
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--accent-sky);
      color: var(--charcoal);
      font-weight: 600;
      padding: 0.8rem 1.9rem;
      border-radius: var(--radius-btn);
      transition: var(--transition-smooth);
      font-family: var(--font-heading);
    }
    .btn-outline:hover {
      background-color: var(--accent-sky);
      color: white;
      border-color: var(--accent-sky);
    }
    .btn-gold {
      background-color: var(--gold);
      color: #1E1D1B;
      font-weight: 700;
      border: none;
      padding: 0.9rem 2.2rem;
      border-radius: var(--radius-btn);
      transition: var(--transition-smooth);
      box-shadow: 0 6px 14px rgba(200,169,110,0.25);
    }
    .btn-gold:hover {
      background-color: var(--gold-hover);
      transform: scale(1.02);
    }
    .card-custom {
      background: white;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      transition: var(--transition-smooth);
      overflow: hidden;
      height: 100%;
    }
    .card-custom:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }
    .bg-dark-section {
      background-color: var(--charcoal);
      color: var(--text-on-dark);
    }
    .bg-dark-section h2 {
      color: white;
    }
    .text-accent {
      color: var(--accent-sky);
    }
    .divider-light {
      height: 1px;
      background: var(--border-light);
      margin: 2rem 0;
    }
    /* 响应式 */
    @media screen and (max-width: 1024px) {
      .app-sidebar {
        transform: translateX(-100%);
      }
      .app-sidebar.mobile-open {
        transform: translateX(0);
      }
      .main-content {
        margin-left: 0;
        width: 100%;
      }
      .mobile-header {
        display: flex;
      }
      .drawer-overlay.active {
        display: block;
      }
      section {
        padding: 3.5rem 0;
      }
      h2 {
        font-size: 2rem;
      }
    }
    @media screen and (max-width: 640px) {
      .container-custom {
        padding: 0 1.2rem;
      }
      .hero-left h1 {
        font-size: 2.4rem;
      }
      .grid-cards {
        grid-template-columns: 1fr;
      }
      .comparison-table {
        flex-direction: column;
      }
    }