/* roulang page: index */
:root {
      --primary: #F04E23;
      --primary-hover: #D13E18;
      --secondary-dark: #1E1E24;
      --gray-bg: #E8ECF1;
      --white: #FFFFFF;
      --accent-yellow: #FFC107;
      --success-green: #0FA47A;
      --text-body: #4A4A55;
      --text-muted: #8C8C9A;
      --border-light: #E8ECF1;
      --shadow-sm: 0 4px 16px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
      --nav-height: 72px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
    }
    body {
      font-family: var(--font-family);
      background-color: var(--white);
      color: var(--text-body);
      line-height: 1.8;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }
    h1, h2, h3, h4 {
      color: var(--secondary-dark);
      font-weight: 600;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      outline: none;
    }
    /* 导航 */
    .main-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background: var(--white);
      border-bottom: 1px solid var(--border-light);
      z-index: 1000;
      display: flex;
      align-items: center;
      transition: box-shadow 0.25s ease;
    }
    .main-header.scrolled {
      box-shadow: 0 4px 12px rgba(0,0,0,0.04);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }
    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--secondary-dark);
      letter-spacing: 1px;
      white-space: nowrap;
    }
    .logo span {
      color: var(--primary);
    }
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }
    .nav-menu a {
      font-weight: 500;
      color: var(--secondary-dark);
      position: relative;
      padding: 8px 0;
      transition: color 0.2s;
      font-size: 15px;
    }
    .nav-menu a:hover,
    .nav-menu a.active {
      color: var(--primary);
    }
    .nav-menu a.active::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 100%;
      height: 3px;
      background: var(--primary);
      border-radius: 2px;
    }
    .nav-cta {
      background: var(--primary);
      color: white;
      padding: 10px 22px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: background 0.2s, box-shadow 0.2s;
      font-size: 15px;
      white-space: nowrap;
      margin-left: 16px;
    }
    .nav-cta:hover {
      background: var(--primary-hover);
      box-shadow: 0 4px 12px rgba(240,78,35,0.3);
    }
    .hamburger {
      display: none;
      font-size: 26px;
      color: var(--secondary-dark);
      background: none;
      border: none;
      cursor: pointer;
    }
    /* 移动端导航 */
    .mobile-menu {
      display: none;
      position: fixed;
      top: var(--nav-height);
      left: 0;
      width: 100%;
      background: var(--white);
      flex-direction: column;
      padding: 24px 20px;
      gap: 20px;
      box-shadow: 0 8px 20px rgba(0,0,0,0.08);
      z-index: 999;
      animation: fadeIn 0.25s ease;
    }
    .mobile-menu.open {
      display: flex;
    }
    .mobile-menu a {
      font-size: 18px;
      font-weight: 500;
      color: var(--secondary-dark);
      padding: 8px 0;
    }
    .mobile-menu .nav-cta {
      margin-left: 0;
      text-align: center;
      display: block;
      width: fit-content;
    }
    @keyframes fadeIn {
      from { opacity: 0; transform: translateY(-10px); }
      to { opacity: 1; transform: translateY(0); }
    }
    /* 板块通用 */
    section {
      padding: 80px 0;
    }
    .section-title {
      font-size: 36px;
      font-weight: 600;
      color: var(--secondary-dark);
      margin-bottom: 16px;
      text-align: center;
    }
    .section-title::after {
      content: '';
      display: block;
      width: 60px;
      height: 4px;
      background: var(--primary);
      margin: 12px auto 0;
      border-radius: 2px;
    }
    .section-sub {
      text-align: center;
      color: var(--text-muted);
      max-width: 680px;
      margin: 0 auto 48px;
      font-size: 17px;
    }
    /* Hero */
    .hero {
      padding: calc(var(--nav-height) + 60px) 0 60px;
      background: linear-gradient(180deg, #F8FAFC 0%, #FFFFFF 100%);
      min-height: 85vh;
      display: flex;
      align-items: center;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 48px;
    }
    .hero-content {
      flex: 1;
    }
    .hero-content h1 {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      letter-spacing: 1px;
      color: var(--secondary-dark);
    }
    .hero-content .highlight {
      color: var(--primary);
    }
    .hero-desc {
      font-size: 18px;
      color: var(--text-body);
      margin: 24px 0 32px;
      line-height: 1.7;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: all 0.25s;
      display: inline-block;
      text-align: center;
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      box-shadow: 0 6px 18px rgba(240,78,35,0.3);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: all 0.25s;
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
    }
    .hero-image {
      flex: 1;
      text-align: right;
    }
    .hero-image img {
      border-radius: 24px;
      box-shadow: var(--shadow-md);
      max-height: 420px;
      object-fit: cover;
    }
    /* 优势卡片 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
      margin-top: 24px;
    }
    .feature-card {
      background: var(--white);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-card);
      padding: 32px 24px;
      box-shadow: var(--shadow-sm);
      transition: all 0.25s ease;
      text-align: center;
    }
    .feature-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-md);
    }
    .feature-icon {
      font-size: 44px;
      color: var(--primary);
      margin-bottom: 20px;
    }
    .feature-card h3 {
      font-size: 20px;
      margin-bottom: 12px;
    }
    /* 产品矩阵 */
    .product-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .product-card {
      background: white;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: all 0.25s;
    }
    .product-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .product-card img {
      width: 100%;
      height: 180px;
      object-fit: cover;
    }
    .product-info {
      padding: 20px;
    }
    .product-info h3 {
      font-size: 20px;
      margin-bottom: 8px;
    }
    /* 场景交替 */
    .scene-row {
      display: flex;
      align-items: center;
      gap: 48px;
      margin-bottom: 80px;
    }
    .scene-row.reverse {
      flex-direction: row-reverse;
    }
    .scene-text {
      flex: 1;
    }
    .scene-text h3 {
      font-size: 28px;
      border-left: 4px solid var(--primary);
      padding-left: 16px;
      margin-bottom: 16px;
    }
    .scene-img {
      flex: 1;
      border-radius: 20px;
      overflow: hidden;
      box-shadow: var(--shadow-sm);
    }
    /* 数据背书 */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      text-align: center;
      margin: 32px 0;
    }
    .stat-number {
      font-size: 40px;
      font-weight: 700;
      color: var(--primary);
    }
    .stat-label {
      color: var(--text-muted);
      margin-top: 4px;
    }
    .trust-badges {
      display: flex;
      justify-content: center;
      gap: 40px;
      margin-top: 32px;
      filter: grayscale(1);
      opacity: 0.7;
      flex-wrap: wrap;
    }
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 20px 0;
    }
    .faq-question {
      font-weight: 600;
      font-size: 18px;
      display: flex;
      align-items: center;
      gap: 12px;
      cursor: pointer;
      color: var(--secondary-dark);
    }
    .faq-question i {
      color: var(--primary);
      font-size: 14px;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-body);
      margin-top: 8px;
      padding-left: 28px;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
    }
    /* CTA band */
    .cta-band {
      background: var(--primary);
      color: white;
      text-align: center;
      padding: 70px 20px;
    }
    .cta-band h2 {
      color: white;
      font-size: 36px;
    }
    .cta-band .btn-light {
      background: white;
      color: var(--primary);
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      margin-top: 24px;
      display: inline-block;
    }
    /* Footer */
    .main-footer {
      background: var(--secondary-dark);
      color: #ccc;
      padding: 48px 0 24px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    .footer-logo {
      font-size: 22px;
      font-weight: 700;
      color: white;
    }
    .footer-links a {
      display: block;
      color: #aaa;
      margin-bottom: 8px;
      transition: color 0.2s;
    }
    .footer-links a:hover { color: var(--primary); }
    .copyright {
      text-align: center;
      border-top: 1px solid #333;
      margin-top: 32px;
      padding-top: 20px;
      color: #888;
    }
    /* 响应式 */
    @media (max-width: 1024px) {
      .features-grid, .product-grid { grid-template-columns: repeat(2,1fr); }
      .stats-grid { grid-template-columns: repeat(2,1fr); }
    }
    @media (max-width: 768px) {
      .nav-menu { display: none; }
      .hamburger { display: block; }
      .hero-grid { flex-direction: column; }
      .hero-content h1 { font-size: 32px; }
      .section-title { font-size: 28px; }
      .features-grid, .product-grid { grid-template-columns: 1fr; }
      .scene-row, .scene-row.reverse { flex-direction: column; }
      .stats-grid { grid-template-columns: 1fr 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
      .btn-primary, .btn-outline { width: 100%; justify-content: center; }
    }