/* roulang page: index */
/* ========== 设计变量与重置 ========== */
    :root {
      --primary: #1A3A5C;
      --primary-light: #2A4F73;
      --accent: #D4A843;
      --accent-hover: #B8912F;
      --bg: #F7F9FC;
      --card-bg: #FFFFFF;
      --text: #2C3E50;
      --text-strong: #0F2440;
      --text-muted: #6B7B8D;
      --border-light: #E8ECF0;
      --shadow-sm: 0 2px 12px rgba(26, 58, 92, 0.08);
      --shadow-md: 0 8px 24px rgba(26, 58, 92, 0.12);
      --shadow-lg: 0 16px 32px rgba(26, 58, 92, 0.15);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --font-number: "Inter", "Segoe UI", "Helvetica Neue", Arial, sans-serif;
    }
    
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    
    html {
      scroll-behavior: smooth;
      scroll-padding-top: 80px;
    }
    
    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    
    a {
      text-decoration: none;
      color: var(--primary);
      transition: color 0.2s ease;
    }
    
    a:hover {
      color: var(--accent);
      text-decoration: underline;
    }
    
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      outline: none;
      transition: all 0.2s ease;
    }
    
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    
    /* ========== 导航栏 ========== */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: #FFFFFF;
      box-shadow: 0 2px 16px rgba(0,0,0,0.06);
      height: 72px;
      display: flex;
      align-items: center;
    }
    
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    
    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-size: 24px;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: 0.5px;
      white-space: nowrap;
    }
    
    .logo i {
      color: var(--accent);
      font-size: 28px;
    }
    
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    
    .nav-link {
      font-size: 16px;
      font-weight: 500;
      color: var(--text);
      position: relative;
      padding: 8px 0;
      transition: color 0.2s;
    }
    
    .nav-link:hover {
      color: var(--primary);
      text-decoration: none;
    }
    
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent);
      transition: width 0.2s ease;
    }
    
    .nav-link:hover::after {
      width: 100%;
    }
    
    .btn-primary {
      background: var(--accent);
      color: #FFFFFF;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      box-shadow: 0 4px 10px rgba(212, 168, 67, 0.3);
      transition: all 0.2s ease;
    }
    
    .btn-primary:hover {
      background: var(--accent-hover);
      transform: scale(1.02);
      box-shadow: 0 6px 14px rgba(184, 145, 47, 0.4);
      text-decoration: none;
      color: #fff;
    }
    
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      display: inline-flex;
      align-items: center;
      gap: 8px;
    }
    
    .btn-outline:hover {
      background: var(--primary);
      color: #fff;
      text-decoration: none;
    }
    
    .mobile-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 28px;
      color: var(--primary);
    }
    
    /* 移动端导航 */
    @media (max-width: 1023px) {
      .nav-menu {
        display: none;
        position: fixed;
        top: 72px;
        left: 0;
        width: 100%;
        background: #FFFFFF;
        flex-direction: column;
        padding: 32px 24px;
        gap: 24px;
        box-shadow: var(--shadow-md);
        z-index: 999;
      }
      
      .nav-menu.active {
        display: flex;
      }
      
      .mobile-toggle {
        display: block;
      }
      
      .header-cta-desktop {
        display: none;
      }
    }
    
    @media (min-width: 1024px) {
      .mobile-toggle {
        display: none;
      }
      .header-cta-mobile {
        display: none;
      }
    }
    
    /* ========== Hero 首屏 ========== */
    .hero {
      background: linear-gradient(135deg, #F7F9FC 0%, #FFFFFF 100%);
      padding: 80px 0 100px;
      display: flex;
      align-items: center;
    }
    
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }
    
    .hero-content h1 {
      font-size: 48px;
      font-weight: 700;
      color: var(--text-strong);
      line-height: 1.25;
      letter-spacing: -0.5px;
      margin-bottom: 20px;
    }
    
    .hero-content .subtitle {
      font-size: 18px;
      color: #5A6B7C;
      margin-bottom: 36px;
      max-width: 480px;
    }
    
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    
    .hero-image {
      background: #E8ECF0;
      border-radius: 16px;
      overflow: hidden;
      box-shadow: var(--shadow-lg);
      aspect-ratio: 5 / 4;
      display: flex;
      align-items: center;
      justify-content: center;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
    }
    
    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 40px;
      }
      .hero-content h1 {
        font-size: 36px;
      }
      .hero-image {
        aspect-ratio: 4/3;
        order: -1;
      }
      .hero {
        padding: 40px 0 60px;
      }
    }
    
    /* ========== 板块通用 ========== */
    .section {
      padding: 100px 0;
    }
    
    .section-heading {
      text-align: center;
      margin-bottom: 60px;
    }
    
    .section-heading h2 {
      font-size: 36px;
      font-weight: 600;
      color: var(--text-strong);
      margin-bottom: 12px;
    }
    
    .section-heading p {
      font-size: 18px;
      color: var(--text-muted);
      max-width: 600px;
      margin: 0 auto;
    }
    
    @media (max-width: 768px) {
      .section {
        padding: 60px 0;
      }
      .section-heading h2 {
        font-size: 30px;
      }
    }
    
    /* 卡片网格 */
    .card-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-sm);
      transition: all 0.25s ease;
      display: flex;
      flex-direction: column;
    }
    
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    
    .card-icon {
      font-size: 32px;
      color: var(--accent);
      margin-bottom: 20px;
    }
    
    .card h3 {
      font-size: 22px;
      font-weight: 600;
      margin-bottom: 8px;
      color: var(--text-strong);
    }
    
    .card p {
      color: var(--text-muted);
      font-size: 15px;
      line-height: 1.6;
    }
    
    @media (max-width: 1023px) {
      .card-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    
    @media (max-width: 640px) {
      .card-grid {
        grid-template-columns: 1fr;
      }
    }
    
    /* 产品卡片带图片 */
    .product-card img {
      width: 100%;
      aspect-ratio: 16/9;
      object-fit: cover;
      border-radius: 8px;
      margin-bottom: 20px;
      background: #E8ECF0;
    }
    
    /* 场景交替布局 */
    .scene-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
      margin-bottom: 80px;
    }
    
    .scene-row.reverse {
      direction: rtl;
    }
    
    .scene-row.reverse .scene-text {
      direction: ltr;
    }
    
    .scene-text h3 {
      font-size: 28px;
      font-weight: 600;
      color: var(--text-strong);
      margin-bottom: 16px;
    }
    
    .scene-text ul {
      list-style: none;
      margin-top: 16px;
    }
    
    .scene-text li {
      margin-bottom: 10px;
      display: flex;
      align-items: center;
      gap: 10px;
    }
    
    .scene-text li i {
      color: var(--accent);
    }
    
    .scene-img {
      background: #E8ECF0;
      border-radius: 12px;
      aspect-ratio: 4/3;
      background-size: cover;
      background-position: center;
    }
    
    @media (max-width: 768px) {
      .scene-row, .scene-row.reverse {
        grid-template-columns: 1fr;
        direction: ltr;
        gap: 24px;
      }
    }
    
    /* 数据卡片 */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      text-align: center;
    }
    
    .stat-item {
      background: #F0F4F8;
      border-radius: var(--radius-card);
      padding: 32px 16px;
    }
    
    .stat-number {
      font-size: 48px;
      font-weight: 700;
      color: var(--accent);
      font-family: var(--font-number);
    }
    
    .stat-label {
      color: var(--text-muted);
      margin-top: 8px;
    }
    
    @media (max-width: 768px) {
      .stats-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 20px 0;
      cursor: pointer;
    }
    
    .faq-question {
      font-size: 18px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-muted);
      padding-top: 0;
    }
    
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-top: 16px;
    }
    
    /* CTA Banner */
    .cta-banner {
      background: var(--primary);
      padding: 80px 0;
      text-align: center;
      color: white;
    }
    
    .cta-banner h2 {
      color: white;
      font-size: 36px;
      margin-bottom: 12px;
    }
    
    /* 页脚 */
    .site-footer {
      background: #0F2440;
      color: #AAB7C4;
      padding: 60px 0 30px;
    }
    
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr;
      gap: 40px;
    }
    
    .footer-logo {
      font-size: 24px;
      font-weight: 700;
      color: white;
      margin-bottom: 12px;
    }
    
    .copyright {
      text-align: center;
      margin-top: 40px;
      font-size: 14px;
      color: #7C8B9A;
    }
    
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }
    
    button:active {
      transform: scale(0.97);
    }