/* roulang page: index */
:root {
      --primary: #4E6EF2;
      --primary-hover: #3A5CE4;
      --primary-light: rgba(78,110,242,0.08);
      --success: #00B578;
      --warning: #FF9F0A;
      --error: #FA5151;
      --bg: #F5F6FA;
      --surface: #FFFFFF;
      --text-primary: #1F2329;
      --text-secondary: #86909C;
      --border-light: #E5E8EF;
      --shadow-card: 0 2px 8px rgba(0,0,0,0.04);
      --shadow-hover: 0 8px 24px rgba(0,0,0,0.06);
      --radius-md: 12px;
      --radius-pill: 24px;
      --space-xs: 8px;
      --space-sm: 16px;
      --space-md: 24px;
      --space-lg: 40px;
      --space-xl: 80px;
      --container: 1200px;
      --header-height: 64px;
      --transition: 200ms ease;
    }

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

    body {
      font-family: "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
      background-color: var(--bg);
      color: var(--text-primary);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      outline: none;
      transition: background var(--transition), box-shadow var(--transition), transform var(--transition);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      font-weight: 500;
    }

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

    /* 导航 */
    .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 rgba(0,0,0,0.04);
      z-index: 1000;
      display: flex;
      align-items: center;
    }

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

    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--text-primary);
      letter-spacing: -0.5px;
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .logo span {
      color: var(--primary);
    }

    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }

    .nav-links a {
      font-size: 16px;
      color: var(--text-primary);
      font-weight: 500;
      transition: color var(--transition);
      white-space: nowrap;
    }

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

    .nav-cta {
      background: var(--primary);
      color: white !important;
      padding: 10px 24px;
      border-radius: var(--radius-md);
      font-weight: 600;
      transition: background var(--transition), box-shadow var(--transition);
    }
    .nav-cta:hover {
      background: var(--primary-hover);
      box-shadow: 0 4px 12px rgba(78,110,242,0.3);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--text-primary);
      border-radius: 2px;
      transition: var(--transition);
    }

    /* 移动端导航抽屉 */
    .mobile-menu {
      position: fixed;
      top: var(--header-height);
      left: 0;
      width: 100%;
      background: white;
      box-shadow: 0 12px 24px rgba(0,0,0,0.06);
      padding: var(--space-md) 0;
      display: none;
      flex-direction: column;
      gap: 8px;
      z-index: 999;
      backdrop-filter: blur(12px);
    }
    .mobile-menu a {
      padding: 12px var(--space-md);
      font-size: 18px;
      font-weight: 500;
      color: var(--text-primary);
      border-radius: var(--radius-md);
    }
    .mobile-menu a:hover {
      background: var(--primary-light);
      color: var(--primary);
    }
    .mobile-menu .nav-cta-mobile {
      background: var(--primary);
      color: white;
      margin: 8px var(--space-md);
      text-align: center;
      border-radius: var(--radius-md);
      font-weight: 600;
      padding: 12px;
    }

    /* Hero */
    .hero {
      padding: calc(var(--header-height) + 48px) 0 80px;
      background: var(--surface);
      display: flex;
      align-items: center;
      min-height: 90vh;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-left h1 {
      font-size: 44px;
      font-weight: 700;
      line-height: 1.3;
      color: var(--text-primary);
      margin-bottom: 16px;
    }
    .hero-left .subtitle {
      font-size: 18px;
      color: var(--text-secondary);
      line-height: 1.6;
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-md);
      font-weight: 600;
      font-size: 16px;
      box-shadow: 0 4px 12px rgba(78,110,242,0.25);
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      transform: translateY(-1px);
      box-shadow: 0 8px 20px rgba(78,110,242,0.35);
    }
    .btn-secondary {
      background: transparent;
      border: 1px solid var(--border-light);
      color: var(--text-primary);
      padding: 14px 32px;
      border-radius: var(--radius-md);
      font-weight: 500;
    }
    .btn-secondary:hover {
      background: #F0F1F5;
      border-color: #ccc;
    }
    .hero-right img {
      width: 100%;
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-hover);
      aspect-ratio: 4/3;
      object-fit: cover;
    }

    /* 亮点网格 */
    .features {
      padding: var(--space-xl) 0;
    }
    .section-title {
      font-size: 32px;
      font-weight: 600;
      margin-bottom: 48px;
      text-align: center;
      color: var(--text-primary);
    }
    .features-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }
    .feature-card {
      background: var(--surface);
      padding: 32px 24px;
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      transition: box-shadow var(--transition), transform var(--transition);
      text-align: left;
    }
    .feature-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }
    .feature-icon {
      font-size: 32px;
      color: var(--primary);
      margin-bottom: 20px;
      display: block;
    }
    .feature-card h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 8px;
    }
    .feature-card p {
      font-size: 14px;
      color: var(--text-secondary);
      line-height: 1.5;
    }

    /* 案例瀑布流 */
    .cases {
      padding: var(--space-xl) 0;
    }
    .masonry {
      columns: 3;
      column-gap: 24px;
    }
    .case-card {
      background: var(--surface);
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      margin-bottom: 24px;
      break-inside: avoid;
      transition: box-shadow var(--transition);
    }
    .case-card:hover {
      box-shadow: var(--shadow-hover);
    }
    .case-card img {
      width: 100%;
      display: block;
      object-fit: cover;
      height: auto;
      aspect-ratio: 16/10;
    }
    .case-content {
      padding: 20px;
    }
    .case-content h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 6px;
    }
    .case-content p {
      font-size: 14px;
      color: var(--text-secondary);
      margin-bottom: 12px;
    }
    .tag {
      display: inline-block;
      background: var(--primary-light);
      color: var(--primary);
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 12px;
      font-weight: 500;
    }

    /* 方案对比 */
    .compare {
      padding: var(--space-xl) 0;
    }
    .compare-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
      align-items: start;
    }
    .compare-card {
      background: var(--surface);
      padding: 32px 24px;
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      text-align: center;
      position: relative;
    }
    .compare-card.recommend {
      background: #EEF1FD;
      border: 1px solid var(--primary);
      box-shadow: 0 8px 24px rgba(78,110,242,0.08);
    }
    .compare-card h3 {
      font-size: 22px;
      font-weight: 600;
      margin-bottom: 12px;
    }
    .compare-list {
      list-style: none;
      margin: 20px 0;
      text-align: left;
    }
    .compare-list li {
      padding: 8px 0;
      font-size: 14px;
      color: var(--text-secondary);
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .compare-list li::before {
      content: "✓";
      color: var(--success);
      font-weight: bold;
    }

    /* FAQ */
    .faq {
      padding: var(--space-xl) 0;
    }
    .faq-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 24px;
    }
    .faq-item {
      background: var(--surface);
      border-radius: var(--radius-md);
      padding: 20px 24px;
      box-shadow: var(--shadow-card);
      cursor: pointer;
      transition: background var(--transition);
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      font-size: 16px;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      font-size: 14px;
      color: var(--text-secondary);
      margin-top: 0;
    }
    .faq-item.active .faq-answer {
      max-height: 150px;
      margin-top: 12px;
    }
    .faq-icon {
      transition: transform 0.2s;
      font-size: 18px;
      color: var(--primary);
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }

    /* CTA 横幅 */
    .cta-banner {
      background: var(--primary);
      padding: 80px 0;
      text-align: center;
      color: white;
      border-radius: 0;
    }
    .cta-banner h2 {
      font-size: 36px;
      font-weight: 700;
      margin-bottom: 12px;
    }
    .cta-banner p {
      font-size: 18px;
      opacity: 0.9;
      margin-bottom: 32px;
    }
    .btn-white {
      background: white;
      color: var(--primary);
      padding: 16px 40px;
      border-radius: var(--radius-md);
      font-weight: 700;
      font-size: 18px;
    }
    .btn-white:hover {
      background: #f0f4ff;
      transform: scale(1.02);
    }

    /* 页脚 */
    .footer {
      background: var(--surface);
      padding: 60px 0 24px;
      color: var(--text-secondary);
      font-size: 14px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      margin-bottom: 40px;
    }
    .footer-brand .logo {
      font-size: 22px;
      margin-bottom: 12px;
    }
    .footer-links h4 {
      font-weight: 600;
      color: var(--text-primary);
      margin-bottom: 16px;
    }
    .footer-links a {
      display: block;
      margin-bottom: 10px;
      color: var(--text-secondary);
    }
    .footer-links a:hover {
      color: var(--primary);
    }
    .copyright {
      border-top: 1px solid var(--border-light);
      padding-top: 24px;
      text-align: center;
      font-size: 13px;
    }

    /* 响应式 */
    @media (max-width: 1024px) {
      .features-grid { grid-template-columns: repeat(2, 1fr); }
      .masonry { columns: 2; }
      .compare-grid { grid-template-columns: 1fr; max-width: 500px; margin: 0 auto; }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero-grid { grid-template-columns: 1fr; }
      .hero-left h1 { font-size: 36px; }
      .features-grid { grid-template-columns: 1fr; }
      .masonry { columns: 1; }
      .faq-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }
    @media (max-width: 520px) {
      .hero-buttons .btn { width: 100%; justify-content: center; }
      .footer-grid { grid-template-columns: 1fr; }
    }