/* roulang page: index */
/* ----- 设计变量 & 重置 ----- */
    :root {
      --primary: #FF5C00;
      --primary-dark: #E05200;
      --primary-light: #FFF0E8;
      --secondary: #0B1A2F;
      --accent: #00E0B8;
      --bg-warm: #F7F4F0;
      --bg-white: #FFFFFF;
      --text-primary: #1A2332;
      --text-secondary: #4A5568;
      --text-light: #CBD5E0;
      --border-light: #E2E8F0;
      --shadow-sm: 0 4px 20px rgba(11, 26, 47, 0.06);
      --shadow-md: 0 8px 30px rgba(11, 26, 47, 0.12);
      --shadow-lg: 0 20px 40px rgba(11, 26, 47, 0.15);
      --radius-md: 12px;
      --radius-sm: 8px;
      --transition: 0.25s ease;
      --font-sans: "Inter", "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --container-max: 1280px;
      --section-gap: 100px;
      --inner-gap: 48px;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-warm);
      color: var(--text-primary);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

    img {
      max-width: 100%;
      height: auto;
      display: block;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }

    button, .btn {
      cursor: pointer;
      font-family: var(--font-sans);
      border: none;
      background: none;
    }

    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 32px;
    }

    /* ----- 导航系统：沉浸式半透明头部 ----- */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: rgba(11, 26, 47, 0.88);
      backdrop-filter: blur(14px);
      -webkit-backdrop-filter: blur(14px);
      border-bottom: 1px solid rgba(255, 255, 255, 0.08);
      transition: var(--transition);
    }

    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }

    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 1.6rem;
      color: #FFFFFF;
      letter-spacing: -0.3px;
    }
    .logo i {
      font-size: 2rem;
      color: var(--primary);
    }
    .logo span {
      color: var(--primary);
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
    }

    .nav-link {
      color: #E2E8F0;
      font-weight: 500;
      font-size: 1rem;
      position: relative;
      padding: 6px 0;
    }

    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width 0.2s ease;
    }

    .nav-link:hover,
    .nav-link.active {
      color: #FFFFFF;
    }
    .nav-link:hover::after,
    .nav-link.active::after {
      width: 100%;
    }

    .mobile-toggle {
      display: none;
      background: transparent;
      color: white;
      font-size: 1.8rem;
      border: none;
      cursor: pointer;
    }

    /* ----- 按钮系统 ----- */
    .btn-primary {
      background: var(--primary);
      color: white;
      font-weight: 600;
      padding: 12px 32px;
      border-radius: var(--radius-sm);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: all 0.25s;
      box-shadow: 0 4px 12px rgba(255, 92, 0, 0.3);
      font-size: 1rem;
      letter-spacing: 0.3px;
    }
    .btn-primary:hover {
      background: #FF7025;
      box-shadow: 0 8px 20px rgba(255, 92, 0, 0.45);
      transform: translateY(-1px);
    }

    .btn-outline {
      border: 2px solid var(--primary);
      color: var(--primary);
      font-weight: 600;
      padding: 10px 30px;
      border-radius: var(--radius-sm);
      background: transparent;
      transition: all 0.25s;
    }
    .btn-outline:hover {
      background: var(--primary-light);
      border-color: var(--primary-dark);
      color: var(--primary-dark);
    }

    /* 主内容区块通用间距 */
    section {
      padding: var(--section-gap) 0;
    }

    .section-title {
      font-size: 2.2rem;
      font-weight: 700;
      margin-bottom: 16px;
      color: var(--secondary);
      letter-spacing: -0.5px;
    }
    .section-sub {
      color: var(--text-secondary);
      max-width: 700px;
      margin-bottom: 48px;
      font-size: 1.1rem;
    }

    /* ----- Hero 首屏 ----- */
    .hero {
      padding: 160px 0 120px;
      background: linear-gradient(135deg, #0B1A2F 0%, #132B44 100%);
      position: relative;
      overflow: hidden;
      color: white;
    }
    .hero::before {
      content: '';
      position: absolute;
      right: -10%;
      top: 10%;
      width: 55%;
      height: 90%;
      background: url('/assets/images/backpic/back-1.webp') no-repeat center/contain;
      opacity: 0.28;
      filter: drop-shadow(0 0 30px rgba(255,92,0,0.4));
      pointer-events: none;
    }
    .hero .container {
      position: relative;
      z-index: 2;
      display: flex;
      align-items: center;
      gap: 40px;
    }
    .hero-content {
      flex: 1;
    }
    .hero h1 {
      font-size: 3.5rem;
      font-weight: 700;
      line-height: 1.15;
      margin-bottom: 24px;
      color: white;
      text-shadow: 0 4px 20px rgba(0,0,0,0.5);
    }
    .hero h1 span {
      color: var(--primary);
    }
    .hero p {
      font-size: 1.2rem;
      margin-bottom: 36px;
      color: rgba(255,255,255,0.85);
      max-width: 500px;
    }
    .hero-actions {
      display: flex;
      gap: 18px;
      flex-wrap: wrap;
    }

    /* 核心优势 非对称布局 */
    .features-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr;
      gap: 28px;
      margin-top: 24px;
    }
    .feature-card {
      background: var(--bg-white);
      border-radius: var(--radius-md);
      padding: 32px 28px;
      box-shadow: var(--shadow-sm);
      transition: all 0.25s;
      border: 1px solid rgba(0,0,0,0.02);
    }
    .feature-card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-5px);
    }
    .feature-card.large {
      grid-row: span 1;
      display: flex;
      flex-direction: column;
      justify-content: center;
    }
    .feature-icon {
      font-size: 2.4rem;
      color: var(--primary);
      margin-bottom: 20px;
    }
    .feature-card h3 {
      font-size: 1.5rem;
      margin-bottom: 14px;
    }

    /* 产品分组 可切换标签 */
    .product-tabs {
      display: flex;
      gap: 16px;
      margin-bottom: 40px;
      flex-wrap: wrap;
    }
    .tab-btn {
      padding: 10px 24px;
      border-radius: 40px;
      background: white;
      border: 1px solid var(--border-light);
      font-weight: 600;
      color: var(--text-secondary);
      transition: 0.2s;
    }
    .tab-btn.active {
      background: var(--primary);
      color: white;
      border-color: var(--primary);
    }
    .product-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .product-card {
      background: white;
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: 0.25s;
    }
    .product-card:hover {
      box-shadow: var(--shadow-md);
    }
    .product-img {
      height: 180px;
      background-size: cover;
      background-position: center;
    }
    .product-info {
      padding: 22px;
    }

    /* 使用场景 */
    .scenario-block {
      display: flex;
      align-items: center;
      gap: 60px;
      background: white;
      border-radius: 24px;
      overflow: hidden;
      box-shadow: var(--shadow-sm);
    }
    .scenario-text {
      padding: 48px;
      flex: 1;
    }
    .scenario-visual {
      flex: 1;
      min-height: 360px;
      background: url('/assets/images/backpic/back-2.webp') center/cover;
    }

    /* 数据看板 */
    .stats-board {
      display: flex;
      justify-content: space-around;
      background: var(--secondary);
      border-radius: 20px;
      padding: 40px 30px;
      color: white;
      margin-bottom: 40px;
      flex-wrap: wrap;
    }
    .stat-item {
      text-align: center;
    }
    .stat-number {
      font-size: 2.8rem;
      font-weight: 700;
      color: var(--accent);
    }
    .case-cards {
      display: flex;
      gap: 24px;
      overflow-x: auto;
    }
    .case-card {
      min-width: 260px;
      background: white;
      border-radius: var(--radius-md);
      padding: 20px;
    }

    /* FAQ 手风琴 */
    .faq-item {
      background: white;
      border-radius: var(--radius-md);
      margin-bottom: 16px;
      border: 1px solid var(--border-light);
      transition: 0.2s;
    }
    .faq-question {
      padding: 20px 28px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }
    .faq-answer {
      padding: 0 28px 20px;
      display: none;
    }
    .faq-item.open {
      border-color: var(--primary);
    }
    .faq-item.open .faq-answer {
      display: block;
    }

    /* CTA band */
    .cta-band {
      background: linear-gradient(135deg, #0B1A2F, #1D3B56);
      border-radius: 28px;
      padding: 70px 40px;
      text-align: center;
      color: white;
    }

    .footer {
      background: var(--secondary);
      color: var(--text-light);
      padding: 60px 0 30px;
    }

    /* 响应式 */
    @media (max-width: 1024px) {
      .features-grid { grid-template-columns: 1fr 1fr; }
      .product-grid { grid-template-columns: repeat(2,1fr); }
      .scenario-block { flex-direction: column; }
    }
    @media (max-width: 768px) {
      .nav-menu { display: none; }
      .mobile-toggle { display: block; }
      .hero h1 { font-size: 2.4rem; }
      .features-grid, .product-grid { grid-template-columns: 1fr; }
      .container { padding: 0 20px; }
      section { padding: 70px 0; }
    }