/* roulang page: index */
:root {
      --primary: #0A9B94;
      --primary-dark: #078A85;
      --accent: #FF6B35;
      --accent-hover: #e55a2b;
      --bg-body: #F8FBFD;
      --text-main: #1A2A3A;
      --text-secondary: #5F6B7A;
      --text-light: #8B95A1;
      --border-light: #E9EDF2;
      --white: #FFFFFF;
      --footer-bg: #1A2A3A;
      --radius-card: 16px;
      --radius-btn: 12px;
      --radius-input: 10px;
      --shadow-card: 0 8px 24px rgba(0,0,0,0.04);
      --shadow-hover: 0 16px 36px rgba(0,0,0,0.08);
      --transition: all 0.25s ease;
      --max-width: 1200px;
      --nav-height: 76px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: "Inter", "PingFang SC", "Microsoft YaHei", "SF Pro Text", sans-serif;
      background-color: var(--bg-body);
      color: var(--text-main);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
      scroll-behavior: smooth;
    }
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 32px;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 20px;
      }
    }
    h1, h2, h3, h4 {
      font-weight: 600;
      line-height: 1.3;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }
    img {
      max-width: 100%;
      display: block;
    }
    button {
      font-family: inherit;
      cursor: pointer;
      border: none;
      background: transparent;
    }
    /* 导航样式 */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: var(--white);
      border-bottom: 1px solid var(--border-light);
      box-shadow: 0 4px 10px rgba(0,0,0,0.02);
      height: var(--nav-height);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 700;
      font-size: 22px;
      color: var(--primary);
    }
    .logo i {
      font-size: 28px;
      color: var(--primary);
    }
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 36px;
      list-style: none;
    }
    .nav-link {
      font-size: 16px;
      font-weight: 500;
      color: var(--text-main);
      position: relative;
      padding: 8px 0;
      transition: var(--transition);
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width 0.2s ease;
    }
    .nav-link:hover {
      color: var(--primary);
    }
    .nav-link:hover::after {
      width: 100%;
    }
    .btn-primary {
      background: var(--primary);
      color: var(--white);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: var(--transition);
      letter-spacing: 0.3px;
      font-size: 16px;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      box-shadow: 0 8px 18px rgba(10,155,148,0.25);
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: var(--transition);
    }
    .btn-outline:hover {
      background: rgba(10,155,148,0.06);
    }
    .mobile-toggle {
      display: none;
      font-size: 28px;
      color: var(--text-main);
    }
    @media (max-width: 992px) {
      .nav-menu {
        gap: 24px;
      }
    }
    @media (max-width: 768px) {
      .mobile-toggle {
        display: block;
      }
      .nav-menu {
        position: fixed;
        top: var(--nav-height);
        left: 0;
        width: 100%;
        background: var(--white);
        flex-direction: column;
        gap: 0;
        padding: 20px;
        box-shadow: 0 20px 30px rgba(0,0,0,0.06);
        transform: translateY(-120%);
        opacity: 0;
        transition: transform 0.3s ease, opacity 0.3s ease;
        z-index: 40;
      }
      .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
      }
      .nav-link {
        padding: 16px 0;
        border-bottom: 1px solid var(--border-light);
        width: 100%;
      }
      .header-cta {
        display: none;
      }
      .mobile-cta {
        display: block;
        margin-top: 20px;
        width: 100%;
      }
    }
    .header-cta .btn-primary {
      padding: 10px 24px;
      font-size: 15px;
    }
    /* Hero */
    .hero {
      padding: 60px 0 80px;
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-content {
      flex: 1;
    }
    .hero-content h1 {
      font-size: 44px;
      font-weight: 700;
      color: var(--text-main);
      margin-bottom: 20px;
      letter-spacing: -0.5px;
    }
    .hero-content .subtitle {
      font-size: 18px;
      color: var(--text-secondary);
      margin-bottom: 36px;
      line-height: 1.6;
    }
    .hero-buttons {
      display: flex;
      gap: 18px;
      flex-wrap: wrap;
    }
    .hero-image {
      flex: 1;
      position: relative;
    }
    .hero-image img {
      border-radius: 32px;
      box-shadow: 0 30px 50px rgba(10,155,148,0.15);
      width: 100%;
      height: auto;
      transform: perspective(800px) rotateY(-3deg);
      transition: var(--transition);
    }
    @media (max-width: 768px) {
      .hero {
        flex-direction: column;
        padding: 40px 0;
        gap: 40px;
      }
      .hero-content h1 {
        font-size: 36px;
      }
      .hero-buttons .btn-primary, .hero-buttons .btn-outline {
        width: 100%;
        justify-content: center;
      }
      .hero-image img {
        transform: none;
      }
    }
    /* 通用板块 */
    .section {
      padding: 90px 0;
    }
    .section-header {
      text-align: center;
      margin-bottom: 60px;
    }
    .section-header h2 {
      font-size: 34px;
      font-weight: 700;
      color: var(--text-main);
    }
    .section-header p {
      color: var(--text-secondary);
      margin-top: 12px;
      font-size: 17px;
    }
    /* 优势卡片 (左图标右文字) */
    .advantages-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }
    .adv-card {
      background: var(--white);
      padding: 32px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      display: flex;
      gap: 24px;
      align-items: flex-start;
      transition: var(--transition);
    }
    .adv-card:hover {
      box-shadow: var(--shadow-hover);
    }
    .adv-icon {
      font-size: 32px;
      color: var(--primary);
      flex-shrink: 0;
    }
    .adv-text h3 {
      font-size: 20px;
      margin-bottom: 8px;
    }
    .adv-text p {
      color: var(--text-secondary);
      font-size: 15px;
    }
    @media (max-width: 992px) {
      .advantages-grid {
        grid-template-columns: 1fr 1fr;
      }
    }
    @media (max-width: 600px) {
      .advantages-grid {
        grid-template-columns: 1fr;
      }
    }
    /* 功能交错布局 */
    .feature-row {
      display: flex;
      align-items: center;
      gap: 70px;
      margin-bottom: 100px;
    }
    .feature-row.reverse {
      flex-direction: row-reverse;
    }
    .feature-img {
      flex: 1;
    }
    .feature-img img {
      border-radius: 24px;
      box-shadow: 0 20px 35px rgba(0,0,0,0.06);
      width: 100%;
    }
    .feature-desc {
      flex: 1;
    }
    .feature-desc h3 {
      font-size: 28px;
      margin-bottom: 16px;
    }
    .feature-desc p {
      color: var(--text-secondary);
      margin-bottom: 20px;
    }
    .feature-desc ul {
      list-style: none;
    }
    .feature-desc li {
      margin-bottom: 10px;
      display: flex;
      align-items: center;
      gap: 10px;
      color: var(--text-main);
    }
    .feature-desc li i {
      color: var(--primary);
    }
    @media (max-width: 768px) {
      .feature-row, .feature-row.reverse {
        flex-direction: column;
        gap: 30px;
        margin-bottom: 70px;
      }
    }
    /* 场景卡片 */
    .scenarios-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 30px;
    }
    .scenario-card {
      background: var(--white);
      border-radius: 20px;
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
      background: #F0F4F8;
    }
    .scenario-card:hover {
      transform: translateY(-8px);
      box-shadow: var(--shadow-hover);
    }
    .scenario-img {
      height: 200px;
      background-size: cover;
      background-position: center;
      transition: transform 0.4s;
    }
    .scenario-card:hover .scenario-img {
      transform: scale(1.04);
    }
    .scenario-text {
      padding: 24px;
    }
    .scenario-text h4 {
      font-size: 20px;
      margin-bottom: 10px;
    }
    @media (max-width: 768px) {
      .scenarios-grid {
        grid-template-columns: 1fr;
      }
    }
    /* 案例/数据 */
    .stats-grid {
      display: flex;
      justify-content: space-around;
      flex-wrap: wrap;
      gap: 30px;
      margin: 30px 0 40px;
    }
    .stat-item {
      text-align: center;
    }
    .stat-number {
      font-size: 42px;
      font-weight: 700;
      color: var(--primary);
    }
    .stat-label {
      color: var(--text-secondary);
    }
    .logo-wall {
      display: flex;
      justify-content: center;
      flex-wrap: wrap;
      gap: 40px;
      margin-top: 40px;
      filter: grayscale(1);
      opacity: 0.7;
    }
    .logo-wall span {
      font-weight: 600;
      font-size: 18px;
      color: var(--text-main);
    }
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 24px 0;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      font-size: 18px;
      cursor: pointer;
      position: relative;
      padding-left: 16px;
    }
    .faq-question::before {
      content: '';
      position: absolute;
      left: 0;
      top: 4px;
      height: 24px;
      width: 4px;
      background: var(--primary);
      border-radius: 4px;
      transition: 0.2s;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-secondary);
      padding-left: 16px;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      margin-top: 16px;
    }
    .faq-item.active .faq-question::before {
      background: var(--primary);
      height: 28px;
    }
    /* CTA */
    .cta-band {
      background: rgba(10,155,148,0.06);
      text-align: center;
      padding: 80px 20px;
      border-radius: 32px;
      margin: 40px 0;
    }
    .download-btns {
      display: flex;
      justify-content: center;
      gap: 24px;
      margin-top: 32px;
      flex-wrap: wrap;
    }
    .btn-dark {
      background: #1A2A3A;
      color: white;
      padding: 14px 36px;
      border-radius: 40px;
      display: flex;
      align-items: center;
      gap: 12px;
      font-weight: 600;
    }
    /* Footer */
    .footer {
      background: var(--footer-bg);
      color: #CBD5E0;
      padding: 70px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer-logo {
      font-size: 24px;
      font-weight: 700;
      color: white;
      margin-bottom: 14px;
    }
    .footer a {
      color: #CBD5E0;
    }
    .footer a:hover {
      color: var(--primary);
    }
    .copyright {
      border-top: 1px solid #2D3A4A;
      margin-top: 50px;
      padding-top: 25px;
      text-align: center;
      font-size: 14px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
      .section {
        padding: 60px 0;
      }
    }