/* roulang page: index */
:root {
      --primary: #1A3A5C;
      --primary-dark: #0F2A44;
      --accent: #E85D04;
      --accent-dark: #C94A00;
      --bg: #F7F9FC;
      --card-bg: #FFFFFF;
      --text: #2C3E50;
      --text-secondary: #5A6F7E;
      --border: #E1E8EE;
      --radius-card: 16px;
      --radius-btn: 8px;
      --radius-img: 8px;
      --shadow-card: 0 8px 28px rgba(26, 58, 92, 0.06);
      --shadow-card-hover: 0 14px 36px rgba(26, 58, 92, 0.12);
      --shadow-btn: 0 4px 12px rgba(232, 93, 4, 0.25);
      --shadow-btn-hover: 0 6px 18px rgba(232, 93, 4, 0.4);
      --font-sans: -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --transition: 0.3s ease;
      --container-max: 1200px;
      --section-gap: 88px;
    }

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

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

    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }

    img {
      max-width: 100%;
      display: block;
      height: auto;
      border-radius: var(--radius-img);
    }

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

    button, .btn {
      cursor: pointer;
      font-family: var(--font-sans);
      border: none;
      background: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      font-weight: 600;
      transition: var(--transition);
      border-radius: var(--radius-btn);
    }

    /* 导航栏 */
    #header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255, 255, 255, 0.92);
      backdrop-filter: blur(12px);
      box-shadow: 0 2px 12px rgba(0,0,0,0.02);
      transition: var(--transition);
    }
    #header.scrolled {
      box-shadow: 0 8px 24px rgba(0,0,0,0.06);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 70px;
    }
    .logo {
      font-size: 1.8rem;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: 1px;
    }
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-link {
      font-size: 1rem;
      font-weight: 500;
      color: var(--text);
      position: relative;
      padding: 6px 0;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 50%;
      width: 0;
      height: 2px;
      background: var(--accent);
      transition: 0.25s ease;
      transform: translateX(-50%);
    }
    .nav-link:hover::after {
      width: 100%;
    }
    .nav-link:hover {
      color: var(--accent);
    }
    .btn-primary {
      background: var(--accent);
      color: white;
      padding: 10px 26px;
      box-shadow: var(--shadow-btn);
    }
    .btn-primary:hover {
      background: var(--accent-dark);
      box-shadow: var(--shadow-btn-hover);
      transform: translateY(-1px);
    }
    .btn-outline {
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 10px 26px;
      background: transparent;
    }
    .btn-outline:hover {
      background: rgba(26,58,92,0.06);
      border-color: var(--accent);
      color: var(--accent);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
    }
    .hamburger span {
      width: 26px;
      height: 2px;
      background: var(--primary);
      transition: 0.3s;
    }

    /* Hero */
    #hero {
      display: flex;
      align-items: center;
      gap: 50px;
      padding: 40px 0 60px;
      min-height: 85vh;
    }
    .hero-content {
      flex: 1 1 50%;
    }
    .hero-content h1 {
      font-size: 3.4rem;
      font-weight: 700;
      line-height: 1.2;
      color: var(--primary);
      margin-bottom: 24px;
    }
    .hero-sub {
      font-size: 1.2rem;
      color: var(--text-secondary);
      margin-bottom: 36px;
      max-width: 500px;
    }
    .hero-buttons {
      display: flex;
      gap: 18px;
      flex-wrap: wrap;
    }
    .hero-image {
      flex: 1 1 45%;
      position: relative;
      border-radius: 24px;
      overflow: hidden;
      box-shadow: var(--shadow-card);
    }
    .hero-image img {
      width: 100%;
      height: auto;
      object-fit: cover;
      border-radius: 24px;
      aspect-ratio: 4/3;
    }

    /* 区块标题 */
    .section-title {
      font-size: 2rem;
      font-weight: 600;
      color: var(--primary);
      margin-bottom: 16px;
      padding-left: 16px;
      border-left: 5px solid var(--accent);
    }
    .section-desc {
      color: var(--text-secondary);
      margin-bottom: 48px;
      font-size: 1.1rem;
    }

    /* 卡片网格 */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 28px;
    }
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 32px 28px;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
      display: flex;
      flex-direction: column;
    }
    .card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-card-hover);
    }
    .card-icon {
      font-size: 2.6rem;
      color: var(--accent);
      margin-bottom: 20px;
    }
    .card h3 {
      font-size: 1.5rem;
      font-weight: 600;
      color: var(--primary);
      margin-bottom: 12px;
    }
    .card p {
      color: var(--text-secondary);
      font-size: 0.98rem;
    }
    .product-card img {
      height: 200px;
      object-fit: cover;
      width: 100%;
      border-radius: 12px 12px 0 0;
    }
    .product-card .card-body {
      padding: 24px;
    }
    .tag {
      display: inline-block;
      background: transparent;
      border: 1px solid var(--accent);
      color: var(--accent);
      font-size: 0.8rem;
      padding: 4px 12px;
      border-radius: 20px;
      margin-right: 6px;
      margin-bottom: 10px;
    }

    /* 场景 */
    .scenario-row {
      display: flex;
      align-items: center;
      gap: 40px;
      margin-bottom: 60px;
    }
    .scenario-text {
      flex: 1;
    }
    .scenario-img {
      flex: 1;
      border-radius: 20px;
      overflow: hidden;
    }

    /* 案例数字 */
    .case-stat {
      font-size: 2.8rem;
      font-weight: 700;
      color: var(--accent);
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border);
      padding: 20px 0;
    }
    .faq-question {
      font-weight: 600;
      font-size: 1.1rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--primary);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: 0.4s ease;
      color: var(--text-secondary);
      padding-top: 0;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-top: 14px;
    }

    /* CTA 横幅 */
    #cta {
      background: var(--primary);
      padding: 70px 0;
      text-align: center;
      border-radius: 32px;
      margin: 40px 0;
      color: white;
    }

    /* Footer */
    #footer {
      background: #1A2B3C;
      color: #CBD5E1;
      padding: 50px 0 25px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr;
      gap: 40px;
    }

    @media (max-width: 1024px) {
      .grid-3 { grid-template-columns: repeat(2, 1fr); }
      #hero { flex-direction: column; text-align: center; }
      .hero-content h1 { font-size: 2.6rem; }
    }
    @media (max-width: 768px) {
      .nav-menu { display: none; }
      .hamburger { display: flex; }
      .grid-3, .grid-2 { grid-template-columns: 1fr; }
      .scenario-row { flex-direction: column; }
      .footer-grid { grid-template-columns: 1fr; }
      .section-title { font-size: 1.7rem; }
    }