/* roulang page: index */
:root {
      --primary: #4E6EF2;
      --primary-dark: #3A53D1;
      --primary-soft: rgba(78, 110, 242, 0.08);
      --primary-hover-bg: rgba(78, 110, 242, 0.15);
      --accent: #6C5CE7;
      --green: #00B578;
      --orange: #FF9F0A;
      --red: #FA5151;
      --bg: #F5F6FA;
      --white: #FFFFFF;
      --text-primary: #1F2329;
      --text-secondary: #86909C;
      --border: #E5E8EF;
      --radius-lg: 12px;
      --radius-full: 999px;
      --shadow-sm: 0 2px 12px rgba(0, 0, 0, 0.04);
      --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.08);
      --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
      --transition: 200ms ease;
      --section-gap: 80px;
      --container-padding: 24px;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text-primary);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
    }

    img {
      max-width: 100%;
      height: auto;
      display: block;
    }

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

    button, input {
      font-family: inherit;
      outline: none;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 var(--container-padding);
    }

    /* 导航 */
    .site-header {
      background: var(--white);
      border-bottom: 1px solid var(--border);
      position: sticky;
      top: 0;
      z-index: 50;
      height: 64px;
      display: flex;
      align-items: center;
    }

    .header-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }

    .logo {
      font-size: 20px;
      font-weight: 700;
      color: var(--text-primary);
      letter-spacing: 0.5px;
    }
    .logo span {
      color: var(--primary);
    }

    .nav-links {
      display: flex;
      gap: 28px;
      align-items: center;
    }

    .nav-links a {
      font-size: 16px;
      color: var(--text-secondary);
      font-weight: 500;
      position: relative;
      padding: 4px 0;
    }

    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
    }

    .nav-links a.active::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 100%;
      height: 2px;
      background: var(--primary);
      border-radius: 2px;
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
      width: 28px;
      padding: 6px 0;
    }

    .hamburger span {
      display: block;
      height: 2px;
      background: var(--text-primary);
      border-radius: 2px;
      transition: var(--transition);
    }

    .mobile-menu {
      display: none;
      position: fixed;
      top: 0;
      right: 0;
      width: 75%;
      max-width: 320px;
      height: 100vh;
      background: var(--white);
      box-shadow: -8px 0 20px rgba(0,0,0,0.08);
      z-index: 100;
      flex-direction: column;
      padding: 24px;
      transform: translateX(100%);
      transition: transform 0.25s ease;
    }

    .mobile-menu.open {
      transform: translateX(0);
    }

    .mobile-menu .close-btn {
      align-self: flex-end;
      background: none;
      border: none;
      font-size: 28px;
      color: var(--text-primary);
      cursor: pointer;
    }

    .mobile-menu a {
      font-size: 20px;
      padding: 16px 0;
      border-bottom: 1px solid var(--border);
      color: var(--text-primary);
      font-weight: 500;
    }

    /* Hero */
    .hero {
      padding: 60px 0;
      background: var(--white);
      position: relative;
      overflow: hidden;
    }
    .hero .container {
      display: flex;
      align-items: center;
      gap: 40px;
    }
    .hero-left {
      flex: 1;
    }
    .hero-left h1 {
      font-size: 36px;
      font-weight: 700;
      line-height: 1.3;
      color: var(--text-primary);
      margin-bottom: 16px;
    }
    .hero-left .sub {
      font-size: 16px;
      color: var(--text-secondary);
      margin-bottom: 28px;
      max-width: 480px;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      border: none;
      padding: 12px 28px;
      border-radius: var(--radius-lg);
      font-weight: 600;
      font-size: 16px;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      transition: background 0.15s, transform 0.15s;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
    }
    .btn-primary:active {
      transform: scale(0.97);
    }
    .hero-right {
      flex: 1;
      display: flex;
      justify-content: center;
      align-items: center;
    }
    .hero-img-wrapper {
      background: radial-gradient(circle at 30% 40%, rgba(108,92,231,0.2), rgba(78,110,242,0.05));
      border-radius: 16px;
      padding: 20px;
    }
    .hero-img-wrapper img {
      border-radius: 16px;
      box-shadow: var(--shadow-md);
      max-height: 340px;
      object-fit: cover;
    }

    /* 板块通用 */
    .section {
      padding: var(--section-gap) 0;
    }
    .section-title {
      font-size: 28px;
      font-weight: 700;
      color: var(--text-primary);
      margin-bottom: 12px;
    }
    .section-sub {
      font-size: 16px;
      color: var(--text-secondary);
      margin-bottom: 40px;
    }

    /* 核心优势 - 左对齐横排卡片 */
    .features-grid {
      display: flex;
      flex-direction: column;
      gap: 24px;
    }
    .feature-row {
      display: flex;
      align-items: flex-start;
      gap: 20px;
      background: var(--white);
      padding: 24px;
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-sm);
      transition: all var(--transition);
    }
    .feature-row:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-2px);
    }
    .feature-icon {
      width: 48px;
      height: 48px;
      background: rgba(78,110,242,0.08);
      border-radius: var(--radius-lg);
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--primary);
      font-size: 24px;
      flex-shrink: 0;
    }
    .feature-text h3 {
      font-size: 20px;
      font-weight: 700;
      margin-bottom: 8px;
    }
    .feature-text p {
      color: var(--text-secondary);
      font-size: 16px;
      line-height: 1.5;
    }

    /* 解决方案交替布局 */
    .solution-block {
      display: flex;
      gap: 40px;
      align-items: center;
      margin-bottom: 48px;
    }
    .solution-block.reverse {
      flex-direction: row-reverse;
    }
    .solution-content {
      flex: 1;
    }
    .solution-content h3 {
      font-size: 22px;
      font-weight: 700;
      margin-bottom: 12px;
    }
    .solution-content p {
      color: var(--text-secondary);
      margin-bottom: 16px;
    }
    .solution-card {
      flex: 1;
      background: var(--white);
      border-radius: var(--radius-lg);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      border-left: 4px solid var(--accent);
    }
    .solution-card .metric {
      font-size: 28px;
      font-weight: 700;
      color: var(--accent);
    }

    /* 案例横向滑动 */
    .case-scroll {
      display: flex;
      gap: 24px;
      overflow-x: auto;
      padding-bottom: 16px;
      scroll-snap-type: x mandatory;
    }
    .case-card {
      min-width: 280px;
      background: var(--white);
      border-radius: var(--radius-lg);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      scroll-snap-align: start;
      transition: var(--transition);
    }
    .case-card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-2px);
    }
    .case-tag {
      display: inline-block;
      background: rgba(78,110,242,0.1);
      color: var(--primary);
      font-size: 14px;
      padding: 4px 12px;
      border-radius: var(--radius-full);
      margin-bottom: 12px;
    }
    .case-data {
      font-size: 28px;
      font-weight: 700;
      color: var(--accent);
      margin: 8px 0;
    }
    .case-quote {
      font-style: italic;
      color: var(--text-secondary);
      font-size: 14px;
    }

    /* FAQ */
    .faq-list {
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    .faq-item {
      background: var(--white);
      border-radius: var(--radius-lg);
      padding: 20px 24px;
      box-shadow: var(--shadow-sm);
      cursor: pointer;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 700;
      font-size: 16px;
    }
    .faq-icon {
      font-size: 20px;
      color: var(--primary);
      transition: transform 0.2s;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding-top 0.3s;
      color: var(--text-secondary);
      font-size: 16px;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-top: 16px;
    }

    /* CTA 区 */
    .cta-section {
      background: linear-gradient(135deg, #4E6EF2 0%, #6C5CE7 100%);
      padding: 70px 0;
      text-align: center;
    }
    .cta-section h2 {
      color: white;
      font-size: 28px;
      margin-bottom: 12px;
    }
    .cta-section .sub {
      color: rgba(255,255,255,0.8);
      margin-bottom: 28px;
    }
    .btn-ghost {
      background: transparent;
      border: 1.5px solid white;
      color: white;
      padding: 12px 32px;
      border-radius: var(--radius-lg);
      font-weight: 600;
      cursor: pointer;
      transition: background 0.2s;
    }
    .btn-ghost:hover {
      background: rgba(255,255,255,0.15);
    }

    /* 页脚 */
    .footer {
      background: #1F2329;
      color: #86909C;
      padding: 48px 0 24px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 30px;
    }
    .footer h4 {
      color: white;
      margin-bottom: 16px;
      font-size: 16px;
    }
    .footer a {
      color: #86909C;
      display: block;
      margin-bottom: 8px;
      font-size: 14px;
    }
    .copyright {
      margin-top: 32px;
      text-align: center;
      font-size: 12px;
      border-top: 1px solid #2E3238;
      padding-top: 20px;
    }

    @media (max-width: 1024px) {
      .hero .container {
        flex-direction: column;
      }
      .solution-block, .solution-block.reverse {
        flex-direction: column;
      }
      .footer-grid {
        grid-template-columns: repeat(2,1fr);
      }
    }

    @media (max-width: 768px) {
      :root {
        --section-gap: 48px;
      }
      .nav-links {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .mobile-menu {
        display: flex;
      }
      .hero-left h1 {
        font-size: 28px;
      }
      .section-title {
        font-size: 22px;
      }
      .feature-row {
        flex-direction: column;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
      .case-scroll {
        gap: 16px;
      }
    }