/* roulang page: index */
:root {
      --primary: #1A5FDC;
      --primary-dark: #0F3D8C;
      --bg: #F8FAFC;
      --card-bg: #FFFFFF;
      --accent: #F59E0B;
      --success: #10B981;
      --text-heading: #0F172A;
      --text-body: #475569;
      --text-muted: #94A3B8;
      --border: #E2E8F0;
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-tag: 6px;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.04), 0 6px 16px rgba(0,0,0,0.06);
      --shadow-hover: 0 8px 24px rgba(0,0,0,0.10);
      --transition: 0.2s ease;
      --max-width: 1280px;
      --header-height: 72px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
      background: var(--bg);
      color: var(--text-body);
      line-height: 1.7;
      font-size: 1rem;
      padding-top: var(--header-height);
    }
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    img {
      max-width: 100%;
      display: block;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      transition: var(--transition);
      border: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
    }
    h1, h2, h3, h4 {
      color: var(--text-heading);
    }
    h1 {
      font-size: 2.75rem;
      font-weight: 700;
      letter-spacing: -0.02em;
      line-height: 1.2;
    }
    h2 {
      font-size: 2rem;
      font-weight: 700;
      margin-bottom: 1rem;
    }
    h3 {
      font-size: 1.25rem;
      font-weight: 600;
    }
    .section {
      padding: 80px 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 48px;
    }
    .section-title p {
      color: var(--text-muted);
      max-width: 600px;
      margin: 0 auto;
    }

    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: #fff;
      height: var(--header-height);
      z-index: 1000;
      box-shadow: 0 1px 0 var(--border);
      transition: box-shadow 0.2s;
    }
    .header.scrolled {
      box-shadow: 0 2px 8px rgba(0,0,0,0.05);
    }
    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
    }
    .logo {
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--primary);
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .logo i {
      font-size: 1.8rem;
      color: var(--accent);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--text-body);
      transition: color 0.2s;
      font-size: 0.95rem;
    }
    .nav-links a:hover {
      color: var(--primary);
    }
    .btn-nav {
      background: var(--primary);
      color: white !important;
      padding: 10px 22px;
      border-radius: var(--radius-btn);
      font-weight: 600;
    }
    .btn-nav:hover {
      background: var(--primary-dark);
    }
    .hamburger {
      display: none;
      font-size: 1.8rem;
      background: none;
      border: none;
      color: var(--text-heading);
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: var(--header-height);
      left: 0;
      width: 100%;
      background: white;
      flex-direction: column;
      padding: 24px;
      box-shadow: 0 10px 20px rgba(0,0,0,0.08);
      z-index: 999;
      gap: 16px;
    }
    .mobile-menu a {
      font-size: 1.2rem;
      font-weight: 500;
      padding: 8px 0;
      border-bottom: 1px solid var(--border);
    }
    .mobile-menu .btn-nav {
      text-align: center;
      margin-top: 8px;
    }

    /* 按钮体系 */
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 1rem;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
    }
    .btn-outline {
      background: transparent;
      border: 1px solid var(--primary);
      color: var(--primary);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
    }
    .btn-accent {
      background: var(--accent);
      color: #0F172A;
      font-weight: 700;
    }
    .btn-accent:hover {
      background: #d97706;
    }

    /* Hero */
    .hero {
      background: linear-gradient(135deg, #F0F5FF 0%, #FFFFFF 100%);
      border-radius: 0 0 40px 40px;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-content h1 {
      margin-bottom: 16px;
    }
    .hero-content .subtitle {
      font-size: 1.2rem;
      color: var(--text-body);
      margin-bottom: 32px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image img {
      border-radius: 24px;
      box-shadow: 0 20px 35px rgba(26,95,220,0.15);
    }

    /* 卡片通用 */
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      padding: 32px 24px;
      transition: all 0.2s;
      border: 1px solid var(--border);
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }

    /* 特色 */
    .feature-card {
      text-align: center;
    }
    .feature-icon {
      font-size: 2.5rem;
      color: var(--primary);
      margin-bottom: 20px;
    }

    /* 产品卡片 */
    .product-card {
      display: flex;
      flex-direction: column;
    }
    .product-img {
      border-radius: 12px;
      margin-bottom: 20px;
      height: 200px;
      object-fit: cover;
      background: #f1f5f9;
    }
    .feature-list {
      list-style: none;
      margin: 16px 0;
    }
    .feature-list li {
      display: flex;
      align-items: center;
      gap: 10px;
      margin-bottom: 10px;
      color: var(--text-body);
    }
    .feature-list i {
      color: var(--success);
    }

    /* 案例 */
    .case-card {
      background: #fff;
      border-radius: var(--radius-card);
      padding: 24px;
    }
    .case-tag {
      background: #EFF6FF;
      color: var(--primary);
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 0.8rem;
      font-weight: 600;
      display: inline-block;
      margin-bottom: 12px;
    }
    .case-number {
      font-size: 2rem;
      font-weight: 700;
      color: var(--accent);
    }

    /* 价格 */
    .pricing-card {
      text-align: center;
      position: relative;
    }
    .pricing-card.recommended {
      border: 2px solid var(--primary);
      box-shadow: var(--shadow-hover);
    }
    .badge {
      background: var(--accent);
      color: #0F172A;
      font-weight: 700;
      padding: 4px 16px;
      border-radius: 20px;
      font-size: 0.8rem;
      position: absolute;
      top: -12px;
      left: 50%;
      transform: translateX(-50%);
      white-space: nowrap;
    }
    .price {
      font-size: 2.5rem;
      font-weight: 800;
      color: var(--text-heading);
      margin: 20px 0;
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border);
      padding: 18px 0;
    }
    .faq-question {
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      font-size: 1.1rem;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-body);
      padding-right: 40px;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-top: 12px;
    }

    /* CTA */
    .cta-band {
      background: var(--primary);
      border-radius: 24px;
      text-align: center;
      padding: 60px 24px;
      color: white;
    }
    .cta-band h2 {
      color: white;
    }

    /* 页脚 */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer-bottom {
      background: #0F172A;
      color: var(--text-muted);
      padding: 20px 0;
      margin-top: 40px;
      text-align: center;
    }

    @media (max-width: 1024px) {
      h1 { font-size: 2.2rem; }
      .grid-3 { grid-template-columns: repeat(2,1fr); }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: block; }
      .hero-grid { grid-template-columns: 1fr; }
      .grid-3, .grid-2, .footer-grid { grid-template-columns: 1fr; }
      h1 { font-size: 2rem; }
      h2 { font-size: 1.5rem; }
      .section { padding: 60px 0; }
    }
    @media (max-width: 520px) {
      .container { padding: 0 16px; }
    }