/* roulang page: index */
:root {
      --primary: #0A66C2;
      --primary-hover: #084D94;
      --accent: #F5A623;
      --accent-hover: #E09515;
      --bg: #F8FAFC;
      --surface: #FFFFFF;
      --text: #1E293B;
      --text-soft: #64748B;
      --border: #E2E8F0;
      --shadow-sm: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
      --radius: 12px;
      --radius-btn: 8px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --font-mono: "Inter", "SF Mono", monospace;
      --transition: 0.2s ease;
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }
    h1, h2, h3 {
      font-weight: 600;
      line-height: 1.3;
    }
    h1 { font-size: 2.25rem; font-weight: 700; }
    h2 { font-size: 1.75rem; }
    h3 { font-size: 1.25rem; }
    .text-mono {
      font-family: var(--font-mono);
    }
    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.96);
      backdrop-filter: blur(6px);
      z-index: 50;
      height: 64px;
      display: flex;
      align-items: center;
      transition: box-shadow 0.3s;
      border-bottom: 1px solid transparent;
    }
    .header.scrolled {
      box-shadow: 0 1px 8px rgba(0,0,0,0.06);
      border-bottom-color: var(--border);
    }
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo {
      font-weight: 700;
      font-size: 1.4rem;
      color: var(--primary);
      display: flex;
      align-items: center;
      gap: 6px;
      text-decoration: none;
    }
    .logo i {
      font-size: 1.5rem;
      color: var(--accent);
    }
    .nav-links {
      display: flex;
      gap: 2rem;
      align-items: center;
    }
    .nav-links a {
      text-decoration: none;
      color: #475569;
      font-weight: 500;
      font-size: 0.95rem;
      transition: color var(--transition);
      white-space: nowrap;
    }
    .nav-links a:hover {
      color: var(--primary);
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      text-decoration: none;
      display: inline-block;
      transition: background var(--transition), box-shadow var(--transition);
      border: none;
      cursor: pointer;
      font-size: 0.95rem;
      box-shadow: 0 2px 6px rgba(10,102,194,0.2);
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      box-shadow: 0 4px 12px rgba(10,102,194,0.3);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      text-decoration: none;
      display: inline-block;
      transition: all var(--transition);
      cursor: pointer;
    }
    .btn-outline:hover {
      background: #E8F1FB;
    }
    .btn-accent {
      background: var(--accent);
      color: white;
      border: none;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      cursor: pointer;
      transition: background var(--transition);
      box-shadow: 0 4px 10px rgba(245,166,35,0.25);
    }
    .btn-accent:hover {
      background: var(--accent-hover);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
      padding: 8px;
    }
    .hamburger span {
      display: block;
      width: 24px;
      height: 2px;
      background: var(--text);
      border-radius: 2px;
      transition: 0.3s;
    }
    .mobile-menu {
      position: fixed;
      top: 64px;
      left: 0;
      width: 100%;
      background: white;
      flex-direction: column;
      align-items: center;
      padding: 2rem;
      gap: 1.8rem;
      transform: translateY(-120%);
      opacity: 0;
      transition: 0.3s ease;
      box-shadow: 0 10px 20px rgba(0,0,0,0.05);
      display: flex;
      z-index: 40;
    }
    .mobile-menu.active {
      transform: translateY(0);
      opacity: 1;
    }
    /* 卡片与组件 */
    .card {
      background: var(--surface);
      border-radius: var(--radius);
      box-shadow: var(--shadow-sm);
      padding: 24px;
      transition: all 0.3s ease;
      height: 100%;
    }
    .card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-4px);
    }
    .data-number {
      font-size: 2.25rem;
      font-weight: 800;
      color: var(--primary);
      font-family: var(--font-mono);
    }
    .service-card {
      border: 1px solid transparent;
    }
    .service-card:hover {
      border-color: var(--primary);
    }
    .tag {
      background: #E8F1FB;
      color: var(--primary);
      padding: 2px 10px;
      border-radius: 4px;
      font-size: 0.75rem;
      font-weight: 500;
      display: inline-block;
    }
    .faq-item {
      border-bottom: 1px solid var(--border);
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 16px 0;
      cursor: pointer;
      font-weight: 600;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s;
      color: var(--text-soft);
      font-size: 0.95rem;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 16px;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    .faq-icon {
      transition: 0.3s;
      font-size: 1.2rem;
      color: var(--primary);
    }
    .comparison-list li {
      display: flex;
      align-items: center;
      gap: 10px;
      margin-bottom: 12px;
    }
    @media (max-width: 768px) {
      h1 { font-size: 1.75rem; }
      h2 { font-size: 1.4rem; }
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .container { padding: 0 16px; }
      .card { padding: 20px; }
    }