/* roulang page: index */
:root {
      --primary-dark: #1A1A1A;
      --gold-accent: #C8A45C;
      --gold-deep: #B8933E;
      --gold-light: #E8D5A3;
      --sand-bg: #F5F0E8;
      --warm-gray: #3D3830;
      --off-white: #FAFAFA;
      --card-border: #E8E3DB;
      --shadow-sm: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 28px rgba(0,0,0,0.08);
      --gold-glow: 0 4px 14px rgba(200,164,92,0.3);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
      --transition-smooth: 0.3s ease;
      --nav-width: 72px;
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--off-white);
      color: var(--primary-dark);
      line-height: 1.7;
      display: flex;
      min-height: 100vh;
      overflow-x: hidden;
    }

    /* 左侧竖向导航 (桌面端) */
    .side-nav {
      position: fixed;
      left: 0;
      top: 0;
      width: var(--nav-width);
      height: 100vh;
      background-color: var(--primary-dark);
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      padding: 24px 0;
      z-index: 1000;
      transition: var(--transition-smooth);
    }

    .logo-area {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 8px;
      width: 100%;
    }

    .logo-icon {
      font-size: 28px;
      font-weight: 700;
      color: var(--gold-accent);
      letter-spacing: 2px;
      writing-mode: vertical-rl;
      text-orientation: mixed;
      line-height: 1.2;
    }

    .nav-links {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 28px;
      width: 100%;
    }

    .nav-item {
      writing-mode: vertical-rl;
      text-orientation: mixed;
      color: #9e9e9e;
      font-size: 13px;
      font-weight: 500;
      letter-spacing: 1px;
      text-decoration: none;
      padding: 8px 0;
      position: relative;
      transition: color 0.2s;
    }

    .nav-item:hover,
    .nav-item.active {
      color: var(--gold-accent);
    }

    .nav-item.active::before {
      content: '';
      position: absolute;
      left: -8px;
      top: 4px;
      bottom: 4px;
      width: 3px;
      background-color: var(--gold-accent);
      border-radius: 2px;
    }

    .social-placeholder {
      display: flex;
      flex-direction: column;
      gap: 16px;
      color: #5a5a5a;
      font-size: 18px;
    }

    /* 移动端顶部导航 */
    .mobile-header {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 56px;
      background-color: var(--primary-dark);
      align-items: center;
      justify-content: space-between;
      padding: 0 20px;
      z-index: 1100;
    }

    .mobile-logo {
      font-size: 20px;
      font-weight: 700;
      color: var(--gold-accent);
    }

    .hamburger {
      background: none;
      border: none;
      color: var(--gold-accent);
      font-size: 24px;
      cursor: pointer;
      transition: 0.2s;
    }

    .mobile-menu {
      position: fixed;
      top: 56px;
      left: 0;
      width: 100%;
      background-color: rgba(26,26,26,0.98);
      backdrop-filter: blur(8px);
      flex-direction: column;
      padding: 24px 0;
      display: none;
      z-index: 1050;
      border-top: 1px solid var(--gold-accent);
    }

    .mobile-menu.open {
      display: flex;
    }

    .mobile-menu a {
      color: #ccc;
      padding: 14px 32px;
      text-decoration: none;
      font-weight: 500;
      border-bottom: 1px solid #333;
      transition: 0.2s;
    }

    .mobile-menu a:hover {
      color: var(--gold-accent);
      background-color: #222;
    }

    /* 主内容区 */
    .main-content {
      margin-left: var(--nav-width);
      width: calc(100% - var(--nav-width));
      background-color: var(--off-white);
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 40px;
    }

    section {
      padding: 80px 0;
    }

    h2 {
      font-size: 40px;
      font-weight: 700;
      text-align: center;
      margin-bottom: 48px;
      color: var(--primary-dark);
      letter-spacing: -0.5px;
    }

    /* Hero */
    .hero {
      background-color: var(--primary-dark);
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      background-blend-mode: overlay;
      min-height: 100vh;
      display: flex;
      align-items: center;
      position: relative;
      padding: 0 40px;
    }

    .hero::before {
      content: '';
      position: absolute;
      inset: 0;
      background: radial-gradient(circle at 20% 50%, rgba(200,164,92,0.08) 0%, transparent 60%);
      pointer-events: none;
    }

    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 800px;
    }

    .hero h1 {
      font-size: 56px;
      font-weight: 700;
      color: white;
      line-height: 1.1;
      margin-bottom: 20px;
    }

    .hero-sub {
      font-size: 18px;
      color: #d4c5b0;
      margin-bottom: 40px;
    }

    .hero-stats {
      display: flex;
      gap: 48px;
      margin-bottom: 40px;
      flex-wrap: wrap;
    }

    .stat-item .stat-number {
      font-size: 36px;
      font-weight: 700;
      color: var(--gold-accent);
    }

    .stat-label {
      font-size: 14px;
      color: #aaa;
    }

    .btn-group {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }

    .btn-primary {
      background: var(--gold-accent);
      color: white;
      border: none;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      cursor: pointer;
      transition: var(--transition-smooth);
      text-decoration: none;
      display: inline-block;
    }

    .btn-primary:hover {
      background: var(--gold-deep);
      box-shadow: var(--gold-glow);
    }

    .btn-ghost {
      background: transparent;
      border: 1px solid var(--gold-accent);
      color: var(--gold-accent);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      cursor: pointer;
      transition: var(--transition-smooth);
      text-decoration: none;
    }

    .btn-ghost:hover {
      background: rgba(200,164,92,0.1);
    }

    /* 卡片通用 */
    .card {
      background: var(--off-white);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-sm);
      transition: var(--transition-smooth);
    }

    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }

    /* 优势四列 */
    .advantages-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }

    .adv-card i {
      font-size: 32px;
      color: var(--gold-accent);
      margin-bottom: 16px;
    }

    /* 功能矩阵不对称 */
    .features-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr;
      gap: 24px;
    }

    .feature-large {
      grid-row: span 2;
    }

    .tag {
      display: inline-block;
      background: #f0ede6;
      color: var(--warm-gray);
      font-size: 12px;
      padding: 4px 12px;
      border-radius: 20px;
      margin-right: 6px;
    }

    /* 场景卡片 */
    .scenarios-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .scene-img {
      width: 100%;
      aspect-ratio: 16/9;
      object-fit: cover;
      border-radius: var(--radius-card);
      transition: transform 0.4s;
    }

    .scene-card:hover .scene-img {
      transform: scale(1.03);
    }

    /* 案例 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .data-wall {
      display: flex;
      justify-content: space-around;
      margin-bottom: 48px;
      flex-wrap: wrap;
      gap: 24px;
    }

    /* 价格 */
    .pricing-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .pricing-card.recommended {
      border: 2px solid var(--gold-accent);
      box-shadow: var(--shadow-md);
      transform: scale(1.02);
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--card-border);
      padding: 20px 0;
      cursor: pointer;
    }

    .faq-question {
      display: flex;
      justify-content: space-between;
      font-weight: 600;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--warm-gray);
    }

    .faq-item.open .faq-answer {
      max-height: 300px;
      margin-top: 12px;
    }

    /* CTA 区块 */
    .cta-block {
      background: var(--primary-dark);
      background-image: url('/assets/images/backpic/back-2.webp');
      background-size: cover;
      background-blend-mode: overlay;
      text-align: center;
      padding: 80px 20px;
    }

    /* 页脚 */
    .footer {
      background: var(--primary-dark);
      color: #aaa;
      padding: 48px 0 24px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }

    @media (max-width: 1024px) {
      .advantages-grid { grid-template-columns: repeat(2, 1fr); }
      .features-grid { grid-template-columns: 1fr 1fr; }
      .feature-large { grid-row: auto; }
    }

    @media (max-width: 768px) {
      .side-nav { display: none; }
      .mobile-header { display: flex; }
      .main-content { margin-left: 0; width: 100%; }
      .container { padding: 0 24px; }
      .hero { padding: 0 24px; min-height: 90vh; }
      .hero h1 { font-size: 40px; }
      .advantages-grid, .scenarios-grid, .cases-grid, .pricing-grid { grid-template-columns: 1fr; }
      .features-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
    }

    .fade-up {
      opacity: 0;
      transform: translateY(20px);
      transition: 0.6s ease;
    }
    .fade-up.visible {
      opacity: 1;
      transform: translateY(0);
    }