/* roulang page: index */
:root {
      --primary: #2B5F8A;
      --primary-light: #E8F0F7;
      --accent: #F47B3E;
      --accent-light: #FFF3EB;
      --text-primary: #1A1A1A;
      --text-secondary: #5C5C5C;
      --text-muted: #8C8C8C;
      --bg-white: #FFFFFF;
      --bg-light: #F7F9FB;
      --border: #E0E4E8;
      --shadow-sm: 0 2px 12px rgba(0,0,0,0.06);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.10);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Noto Sans SC", sans-serif;
      --font-number: "Inter", "Segoe UI", "Helvetica Neue", sans-serif;
      --transition: 0.3s ease;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      color: var(--text-primary);
      background: var(--bg-white);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s;
    }
    button, input, textarea {
      font-family: inherit;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 20px;
      }
    }

    /* 导航 */
    .nav {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: var(--bg-white);
      border-bottom: 1px solid transparent;
      transition: box-shadow 0.3s;
      height: 64px;
      display: flex;
      align-items: center;
    }
    .nav.scrolled {
      box-shadow: 0 2px 16px rgba(0,0,0,0.06);
      border-bottom-color: var(--border);
    }
    .nav .container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      font-size: 1.8rem;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: -0.5px;
      white-space: nowrap;
    }
    .logo span {
      color: var(--accent);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--text-secondary);
      font-size: 0.95rem;
      position: relative;
      padding: 4px 0;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--accent);
    }
    .nav-links a.active::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 100%;
      height: 2px;
      background: var(--accent);
      border-radius: 2px;
    }
    .nav-cta {
      background: var(--accent);
      color: white !important;
      padding: 10px 22px !important;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: background 0.2s, transform 0.2s;
      margin-left: 12px;
    }
    .nav-cta:hover {
      background: #E0692F;
      transform: scale(1.03);
      color: white !important;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      z-index: 1001;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--text-primary);
      transition: 0.3s;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: white;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      gap: 28px;
      z-index: 999;
    }
    .mobile-menu a {
      font-size: 1.4rem;
      font-weight: 600;
      color: var(--text-primary);
    }
    .mobile-menu .nav-cta {
      margin-left: 0;
      font-size: 1.2rem;
      padding: 12px 32px;
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .mobile-menu.active { display: flex; }
      .nav { height: 56px; }
    }

    /* 板块间距 */
    section {
      padding: 100px 0;
    }
    @media (max-width: 768px) {
      section { padding: 60px 0; }
    }

    /* Hero */
    .hero {
      background: var(--bg-white);
      min-height: 80vh;
      display: flex;
      align-items: center;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-content h1 {
      font-size: 44px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--text-primary);
      margin-bottom: 20px;
    }
    .hero-content p {
      font-size: 18px;
      color: var(--text-secondary);
      margin-bottom: 32px;
      max-width: 400px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--accent);
      color: white;
      border: none;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      cursor: pointer;
      transition: 0.2s;
      display: inline-block;
      text-align: center;
    }
    .btn-primary:hover {
      background: #E0692F;
      transform: scale(1.03);
    }
    .btn-secondary {
      background: transparent;
      color: var(--primary);
      border: 2px solid var(--primary);
      padding: 12px 30px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      cursor: pointer;
      transition: 0.2s;
      display: inline-block;
    }
    .btn-secondary:hover {
      background: var(--primary);
      color: white;
    }
    .hero-image img {
      border-radius: 16px;
      box-shadow: var(--shadow-md);
    }
    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        text-align: center;
      }
      .hero-content h1 {
        font-size: 32px;
      }
      .hero-content p {
        max-width: 100%;
      }
      .hero-buttons {
        justify-content: center;
      }
      .hero-image {
        order: -1;
      }
    }

    /* 价值主张 */
    .value-props {
      background: var(--bg-light);
    }
    .value-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 60px;
      text-align: center;
    }
    .value-item {
      display: flex;
      flex-direction: column;
      align-items: center;
    }
    .value-number {
      font-family: var(--font-number);
      font-size: 56px;
      font-weight: 700;
      color: var(--accent);
      line-height: 1;
      margin-bottom: 12px;
    }
    .value-keyword {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 8px;
    }
    .value-desc {
      color: var(--text-secondary);
      font-size: 15px;
      max-width: 220px;
    }
    .value-divider {
      width: 40px;
      height: 2px;
      background: var(--primary);
      margin: 16px auto;
    }
    @media (max-width: 768px) {
      .value-grid {
        grid-template-columns: 1fr;
        gap: 48px;
      }
    }

    /* 功能 */
    .section-title {
      text-align: center;
      font-size: 34px;
      font-weight: 600;
      margin-bottom: 16px;
    }
    .section-subtitle {
      text-align: center;
      color: var(--text-secondary);
      margin-bottom: 48px;
      font-size: 17px;
    }
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .feature-card {
      background: var(--bg-white);
      border-radius: var(--radius-card);
      padding: 28px;
      box-shadow: var(--shadow-sm);
      border: 1px solid var(--border);
      transition: var(--transition);
      display: flex;
      flex-direction: column;
      align-items: flex-start;
    }
    .feature-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .feature-icon {
      width: 52px;
      height: 52px;
      background: var(--primary-light);
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary);
      font-size: 24px;
    }
    .feature-card h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 10px;
    }
    .feature-card p {
      color: var(--text-secondary);
      font-size: 15px;
      line-height: 1.6;
    }
    @media (max-width: 1024px) {
      .features-grid { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 768px) {
      .features-grid { grid-template-columns: 1fr; }
    }

    /* 场景 */
    .scenarios {
      background: var(--primary-light);
    }
    .scenario-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .scenario-card {
      background: white;
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }
    .scenario-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .scenario-img {
      height: 180px;
      background-size: cover;
      background-position: center;
    }
    .scenario-text {
      padding: 20px;
    }
    .scenario-text h4 {
      font-weight: 600;
      font-size: 18px;
      margin-bottom: 6px;
    }
    .scenario-text p {
      color: var(--text-secondary);
      font-size: 14px;
    }
    @media (max-width: 768px) {
      .scenario-grid { grid-template-columns: 1fr; }
    }

    /* 案例/数据 */
    .cases-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .case-list {
      display: flex;
      flex-direction: column;
      gap: 24px;
    }
    .case-item {
      border-left: 4px solid var(--accent);
      padding-left: 20px;
    }
    .case-item h5 {
      font-weight: 600;
      font-size: 18px;
    }
    .case-item p {
      color: var(--text-secondary);
      font-size: 15px;
    }
    .data-metrics {
      display: flex;
      flex-direction: column;
      gap: 28px;
    }
    .metric {
      display: flex;
      align-items: baseline;
      gap: 8px;
    }
    .metric-number {
      font-family: var(--font-number);
      font-size: 48px;
      font-weight: 700;
      color: var(--accent);
      line-height: 1;
    }
    .metric-unit {
      font-size: 20px;
      color: var(--text-secondary);
    }
    @media (max-width: 768px) {
      .cases-grid { grid-template-columns: 1fr; }
    }

    /* 价格 */
    .pricing-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .pricing-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-sm);
      border: 1px solid var(--border);
      text-align: center;
      transition: var(--transition);
      display: flex;
      flex-direction: column;
    }
    .pricing-card.featured {
      border: 2px solid var(--primary);
      background: var(--primary-light);
    }
    .pricing-card h4 {
      font-size: 22px;
      margin-bottom: 12px;
    }
    .price {
      font-family: var(--font-number);
      font-size: 42px;
      font-weight: 700;
      color: var(--primary);
      margin: 16px 0;
    }
    .pricing-card ul {
      list-style: none;
      margin: 24px 0;
      text-align: left;
      color: var(--text-secondary);
      flex: 1;
    }
    .pricing-card li {
      margin-bottom: 10px;
      font-size: 15px;
    }
    .btn-price {
      background: var(--primary);
      color: white;
      padding: 12px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      margin-top: auto;
      transition: 0.2s;
    }
    .btn-price:hover {
      background: var(--accent);
    }
    @media (max-width: 768px) {
      .pricing-grid { grid-template-columns: 1fr; }
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border);
    }
    .faq-question {
      background: white;
      padding: 20px 0;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
      font-size: 17px;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-secondary);
      padding-right: 20px;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 16px;
    }
    .faq-icon {
      transition: transform 0.3s;
    }
    .faq-item.active .faq-icon {
      transform: rotate(180deg);
    }

    /* 联系 CTA */
    .contact-cta {
      background: var(--primary-light);
      text-align: center;
    }
    .contact-form {
      max-width: 500px;
      margin: 32px auto 0;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    .contact-form input,
    .contact-form textarea {
      padding: 12px 16px;
      border: 1px solid var(--border);
      border-radius: var(--radius-btn);
      font-size: 16px;
    }
    .contact-form button {
      align-self: center;
    }

    /* 页脚 */
    .footer {
      background: #1A1A1A;
      color: #B0B0B0;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      margin-bottom: 40px;
    }
    .footer h5 {
      color: white;
      margin-bottom: 16px;
      font-size: 16px;
    }
    .footer a {
      color: #B0B0B0;
      display: block;
      margin-bottom: 8px;
      font-size: 14px;
    }
    .footer a:hover {
      color: var(--accent);
    }
    .copyright {
      border-top: 1px solid #333;
      padding-top: 24px;
      text-align: center;
      font-size: 14px;
    }
    @media (max-width: 768px) {
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }