/* roulang page: index */
:root {
      --primary: #E60012;
      --primary-dark: #c4000f;
      --primary-light: #ff1a2e;
      --bg-white: #FFFFFF;
      --bg-light: #F5F6FA;
      --text-primary: #1F2329;
      --text-secondary: #86909C;
      --text-on-primary: #ffffff;
      --success: #00B578;
      --warning: #FF9F0A;
      --border: #e5e6eb;
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --shadow-sm: 0 4px 12px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.06);
      --shadow-lg: 0 12px 36px rgba(0,0,0,0.08);
      --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
      --container-max: 1200px;
      --header-height: 72px;
      --transition: 0.25s cubic-bezier(0.2, 0.0, 0.0, 1);
    }
    * { margin: 0; padding: 0; box-sizing: border-box; }
    html { scroll-behavior: smooth; }
    body {
      font-family: var(--font-sans);
      background: var(--bg-white);
      color: var(--text-primary);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    img { max-width: 100%; height: auto; display: block; }
    a { text-decoration: none; color: inherit; transition: color var(--transition); }
    ul { list-style: none; }
    button, .btn { cursor: pointer; font-family: inherit; border: none; background: none; }
    
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
      width: 100%;
    }
    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--header-height);
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      box-shadow: 0 1px 0 var(--border);
      z-index: 100;
      display: flex;
      align-items: center;
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      font-size: 1.8rem;
      font-weight: 700;
      color: var(--text-primary);
      letter-spacing: -0.5px;
    }
    .logo span {
      color: var(--primary);
    }
    .nav-links {
      display: flex;
      gap: 2rem;
      font-weight: 500;
      color: var(--text-secondary);
    }
    .nav-links a {
      position: relative;
      padding: 0.25rem 0;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width var(--transition);
    }
    .nav-links a:hover::after,
    .nav-links a.active::after { width: 100%; }
    .mobile-menu-btn {
      display: none;
      font-size: 1.8rem;
      color: var(--text-primary);
    }
    @media (max-width: 768px) {
      .nav-links {
        display: none;
        position: absolute;
        top: var(--header-height);
        left: 0;
        width: 100%;
        background: white;
        flex-direction: column;
        padding: 1.5rem 2rem;
        box-shadow: var(--shadow-md);
        gap: 1rem;
      }
      .nav-links.open { display: flex; }
      .mobile-menu-btn { display: block; }
    }
    /* 板块通用 */
    section {
      padding: 80px 0;
    }
    @media (max-width: 768px) {
      section { padding: 56px 0; }
    }
    .section-title {
      font-size: 2.2rem;
      font-weight: 700;
      margin-bottom: 0.75rem;
      color: var(--text-primary);
    }
    .section-sub {
      font-size: 1.1rem;
      color: var(--text-secondary);
      max-width: 640px;
      margin: 0 auto 3rem;
    }
    .text-center { text-align: center; }
    /* 按钮 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 0.75rem 2rem;
      border-radius: var(--radius-sm);
      font-weight: 600;
      transition: all var(--transition);
      font-size: 1rem;
    }
    .btn-primary {
      background: var(--primary);
      color: var(--text-on-primary);
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: translateY(-2px);
      box-shadow: 0 8px 18px rgba(230,0,18,0.25);
    }
    .btn-outline {
      border: 1.5px solid var(--border);
      color: var(--text-primary);
      background: transparent;
    }
    .btn-outline:hover {
      border-color: var(--primary);
      color: var(--primary);
      background: #fff5f5;
    }
    .btn-lg { padding: 0.9rem 2.5rem; font-size: 1.1rem; }
    /* Hero */
    .hero {
      padding: calc(var(--header-height) + 60px) 0 60px;
      background: var(--bg-light);
      position: relative;
      overflow: hidden;
    }
    .hero .container {
      display: flex;
      align-items: center;
      gap: 3rem;
    }
    .hero-content {
      flex: 1;
    }
    .hero h1 {
      font-size: 3.2rem;
      font-weight: 800;
      line-height: 1.2;
      margin-bottom: 1.25rem;
    }
    .hero h1 span {
      color: var(--primary);
    }
    .hero p {
      font-size: 1.2rem;
      color: var(--text-secondary);
      margin-bottom: 2rem;
      max-width: 480px;
    }
    .hero-buttons {
      display: flex;
      gap: 1rem;
      flex-wrap: wrap;
    }
    .hero-image {
      flex: 1;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: var(--radius-lg);
      min-height: 360px;
      box-shadow: var(--shadow-lg);
    }
    @media (max-width: 768px) {
      .hero .container {
        flex-direction: column;
        text-align: center;
      }
      .hero h1 { font-size: 2.4rem; }
      .hero-image { width: 100%; min-height: 280px; }
    }
    /* 优势卡片 */
    .card-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .advantage-card {
      background: white;
      padding: 2rem 1.5rem;
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-sm);
      transition: all var(--transition);
      text-align: center;
    }
    .advantage-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-md);
    }
    .advantage-icon {
      font-size: 2.5rem;
      color: var(--primary);
      margin-bottom: 1.25rem;
    }
    .advantage-card h3 {
      font-size: 1.3rem;
      margin-bottom: 0.5rem;
    }
    @media (max-width: 768px) {
      .card-grid { grid-template-columns: 1fr; }
    }
    /* 服务产品大卡片 */
    .service-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 28px;
    }
    .service-card {
      background: white;
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: all var(--transition);
    }
    .service-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-lg);
    }
    .service-img {
      height: 220px;
      background-size: cover;
      background-position: center;
    }
    .service-body {
      padding: 1.5rem;
    }
    .service-body h3 {
      font-size: 1.4rem;
      margin-bottom: 0.5rem;
    }
    .service-body p {
      color: var(--text-secondary);
      margin-bottom: 1rem;
    }
    .service-body .btn-outline {
      padding: 0.5rem 1.5rem;
    }
    @media (max-width: 768px) {
      .service-grid { grid-template-columns: 1fr; }
    }
    /* 使用场景/图文交错 */
    .scenario-row {
      display: flex;
      align-items: center;
      gap: 3rem;
      margin-bottom: 4rem;
    }
    .scenario-row.reverse {
      flex-direction: row-reverse;
    }
    .scenario-text {
      flex: 1;
    }
    .scenario-img {
      flex: 1;
      background-size: cover;
      background-position: center;
      border-radius: var(--radius-md);
      height: 280px;
    }
    @media (max-width: 768px) {
      .scenario-row, .scenario-row.reverse {
        flex-direction: column;
      }
      .scenario-img { width: 100%; }
    }
    /* 案例数据卡片 */
    .case-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .case-card {
      background: white;
      padding: 2rem;
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-sm);
      text-align: center;
      transition: var(--transition);
    }
    .case-card:hover { transform: translateY(-4px); }
    .badge-number {
      font-size: 2.8rem;
      font-weight: 800;
      color: var(--primary);
    }
    .badge-label {
      color: var(--text-secondary);
    }
    @media (max-width: 768px) {
      .case-grid { grid-template-columns: 1fr; }
    }
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border);
      padding: 1.2rem 0;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      font-size: 1.1rem;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-secondary);
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      margin-top: 0.75rem;
    }
    .faq-icon {
      font-size: 1.5rem;
      color: var(--primary);
    }
    /* 最终CTA */
    .cta-section {
      background: linear-gradient(135deg, #E60012 0%, #c4000f 100%);
      border-radius: var(--radius-lg);
      padding: 4rem 2rem;
      text-align: center;
      color: white;
    }
    .cta-section h2 {
      font-size: 2.2rem;
      margin-bottom: 1rem;
    }
    .footer {
      background: var(--bg-light);
      padding: 3rem 0;
      font-size: 0.95rem;
      color: var(--text-secondary);
    }
    .footer-grid {
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 2rem;
    }
    .footer-links {
      display: flex;
      gap: 2rem;
    }
    .footer-links a:hover { color: var(--primary); }