/* roulang page: index */
:root {
      --primary: #0A9E5A;
      --primary-hover: #087A45;
      --secondary: #1E2A38;
      --bg: #F9FAFB;
      --card-bg: #FFFFFF;
      --accent: #E67E22;
      --success: #27AE60;
      --text-primary: #1E2A38;
      --text-secondary: #2C3E50;
      --text-body: #4A5568;
      --text-muted: #A0AEC0;
      --border-light: #E2E8F0;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
      --shadow-md: 0 4px 12px rgba(0,0,0,0.08), 0 2px 4px rgba(0,0,0,0.04);
      --radius-lg: 12px;
      --radius-md: 8px;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
      --font-number: 'Inter', -apple-system, sans-serif;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text-body);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }

    h1, h2, h3, h4 {
      font-weight: 700;
      color: var(--text-primary);
    }

    h1 {
      font-size: clamp(2rem, 5vw, 3rem);
      line-height: 1.3;
    }

    h2 {
      font-size: clamp(1.8rem, 4vw, 2.4rem);
      margin-bottom: 1rem;
    }

    h3 {
      font-size: 1.25rem;
      font-weight: 600;
      color: var(--text-secondary);
    }

    p {
      color: var(--text-body);
      font-weight: 400;
    }

    .container {
      max-width: 1200px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }

    /* 导航 */
    .navbar {
      position: sticky;
      top: 0;
      background: white;
      box-shadow: 0 1px 3px rgba(0,0,0,0.04);
      z-index: 50;
      height: 64px;
      display: flex;
      align-items: center;
      transition: box-shadow 0.2s ease;
    }

    .navbar.scrolled {
      box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    }

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

    .logo {
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--secondary);
      text-decoration: none;
      display: flex;
      align-items: center;
      gap: 0.25rem;
    }

    .logo span {
      color: var(--primary);
    }

    .nav-links {
      display: flex;
      gap: 2rem;
      align-items: center;
    }

    .nav-links a {
      text-decoration: none;
      color: var(--text-body);
      font-weight: 500;
      font-size: 0.95rem;
      transition: color 0.2s;
      position: relative;
      padding-bottom: 4px;
    }

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

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

    .btn-primary {
      background: var(--primary);
      color: white;
      border: none;
      padding: 0.7rem 1.8rem;
      border-radius: var(--radius-md);
      font-weight: 600;
      font-size: 0.95rem;
      cursor: pointer;
      transition: all 0.2s ease;
      display: inline-block;
      text-decoration: none;
      box-shadow: 0 2px 4px rgba(10,158,90,0.2);
    }

    .btn-primary:hover {
      background: var(--primary-hover);
      transform: translateY(-1px);
      box-shadow: 0 6px 14px rgba(10,158,90,0.25);
    }

    .btn-secondary {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      padding: 0.65rem 1.6rem;
      border-radius: var(--radius-md);
      font-weight: 600;
      text-decoration: none;
      display: inline-block;
      transition: all 0.2s ease;
    }

    .btn-secondary:hover {
      background: rgba(10,158,90,0.08);
      border-color: var(--primary-hover);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
      padding: 4px;
    }

    .hamburger span {
      width: 24px;
      height: 2.5px;
      background: var(--secondary);
      border-radius: 2px;
      transition: 0.2s;
    }

    /* 移动端菜单 */
    .mobile-menu {
      display: none;
      position: fixed;
      top: 64px;
      left: 0;
      width: 100%;
      background: white;
      flex-direction: column;
      padding: 2rem;
      gap: 1.8rem;
      box-shadow: var(--shadow-md);
      z-index: 40;
      opacity: 0;
      transform: translateY(-10px);
      transition: opacity 0.2s, transform 0.2s;
    }

    .mobile-menu.active {
      display: flex;
      opacity: 1;
      transform: translateY(0);
    }

    .mobile-menu a {
      font-size: 1.2rem;
      font-weight: 600;
      color: var(--text-primary);
      text-decoration: none;
    }

    /* 卡片与区块 */
    .section {
      padding: 5rem 0;
    }

    .card {
      background: var(--card-bg);
      border-radius: var(--radius-lg);
      padding: 1.8rem;
      box-shadow: var(--shadow-sm);
      transition: all 0.2s ease;
    }

    .card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-2px);
    }

    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 1.5rem;
    }

    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 1.5rem;
    }

    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 1.5rem;
    }

    .icon-circle {
      width: 48px;
      height: 48px;
      background: var(--primary);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 1.5rem;
      margin-bottom: 1rem;
    }

    .stat-number {
      font-family: var(--font-number);
      font-size: 3rem;
      font-weight: 700;
      color: white;
    }

    .footer {
      background: var(--secondary);
      color: #CBD5E0;
      padding: 2.5rem 0;
    }

    @media (max-width: 1024px) {
      .grid-4 { grid-template-columns: repeat(2, 1fr); }
    }

    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
      .section { padding: 3.5rem 0; }
    }

    /* FAQ手风琴 */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      width: 100%;
      background: none;
      border: none;
      padding: 1.2rem 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      font-size: 1.1rem;
      color: var(--text-primary);
      cursor: pointer;
      text-align: left;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
    }
    .faq-answer p {
      padding-bottom: 1.2rem;
    }