/* roulang page: index */
:root {
      --primary: #0A6E7A;
      --primary-hover: #085B65;
      --accent: #F85C3B;
      --accent-hover: #d94a2e;
      --white: #FFFFFF;
      --gray-light: #F5F7FA;
      --gray-border: #E5E7EB;
      --text-dark: #111827;
      --text-body: #374151;
      --text-muted: #6B7280;
      --footer-bg: #1F2937;
      --radius-sm: 8px;
      --radius-md: 12px;
      --shadow-card: 0 1px 3px rgba(0,0,0,0.06), 0 4px 12px rgba(0,0,0,0.04);
      --shadow-hover: 0 8px 24px rgba(0,0,0,0.09), 0 2px 6px rgba(0,0,0,0.04);
      --transition: 0.3s ease;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Inter", "SF Pro Display", system-ui, -apple-system, sans-serif;
      --max-width: 1280px;
      --header-height: 64px;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--white);
      color: var(--text-body);
      line-height: 1.75;
      font-size: 16px;
      display: flex;
      flex-direction: column;
      min-height: 100vh;
    }

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

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

    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 按钮体系 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 12px 28px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 16px;
      cursor: pointer;
      border: 2px solid transparent;
      transition: all var(--transition);
      line-height: 1.2;
      text-align: center;
    }

    .btn-primary {
      background-color: var(--primary);
      color: var(--white);
      border-color: var(--primary);
      box-shadow: 0 2px 6px rgba(10,110,122,0.2);
    }

    .btn-primary:hover {
      background-color: var(--primary-hover);
      border-color: var(--primary-hover);
      transform: translateY(-1px);
      box-shadow: 0 6px 16px rgba(10,110,122,0.3);
    }

    .btn-outline {
      background: transparent;
      color: var(--primary);
      border-color: var(--primary);
    }

    .btn-outline:hover {
      background-color: rgba(10,110,122,0.06);
      color: var(--primary-hover);
    }

    .btn-accent {
      background-color: var(--accent);
      color: var(--white);
      border-color: var(--accent);
      padding: 14px 36px;
      font-size: 17px;
      box-shadow: 0 4px 12px rgba(248,92,59,0.25);
    }

    .btn-accent:hover {
      background-color: var(--accent-hover);
      border-color: var(--accent-hover);
      transform: translateY(-2px);
      box-shadow: 0 8px 20px rgba(248,92,59,0.35);
    }

    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--header-height);
      background: var(--white);
      box-shadow: 0 1px 3px rgba(0,0,0,0.04);
      z-index: 100;
      display: flex;
      align-items: center;
      transition: background var(--transition);
    }

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

    .logo {
      font-weight: 700;
      font-size: 24px;
      color: var(--text-dark);
      display: flex;
      align-items: center;
      gap: 8px;
      letter-spacing: -0.3px;
    }

    .logo span {
      color: var(--primary);
      font-weight: 800;
      background: linear-gradient(135deg, #0A6E7A 0%, #0f8b9c 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }

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

    .nav-links a {
      font-size: 16px;
      font-weight: 500;
      color: var(--text-body);
      padding: 8px 0;
      border-bottom: 2px solid transparent;
      transition: all 0.2s;
    }

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

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
      padding: 8px;
      z-index: 110;
    }

    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--text-dark);
      transition: 0.3s;
      display: block;
    }

    /* 移动端菜单 */
    .mobile-menu {
      position: fixed;
      top: 0;
      right: 0;
      width: 280px;
      height: 100vh;
      background: var(--white);
      box-shadow: -4px 0 20px rgba(0,0,0,0.08);
      transform: translateX(100%);
      transition: transform 0.3s ease;
      padding: 24px;
      display: flex;
      flex-direction: column;
      gap: 24px;
      z-index: 105;
    }

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

    .mobile-menu a {
      font-size: 18px;
      font-weight: 500;
      color: var(--text-dark);
      padding: 12px 0;
      border-bottom: 1px solid var(--gray-border);
    }

    /* 板块间距 */
    section {
      padding: 100px 0;
    }

    .section-title {
      font-size: 32px;
      font-weight: 600;
      color: var(--text-dark);
      margin-bottom: 16px;
      letter-spacing: -0.3px;
    }

    .section-subtitle {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 48px;
      max-width: 700px;
    }

    /* 卡片网格 */
    .grid-3, .grid-4 {
      display: grid;
      gap: 24px;
    }

    .grid-3 {
      grid-template-columns: repeat(3, 1fr);
    }
    .grid-4 {
      grid-template-columns: repeat(4, 1fr);
    }

    .card {
      background: var(--white);
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      overflow: hidden;
      transition: all var(--transition);
    }

    .card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }

    .card-img {
      width: 100%;
      height: 200px;
      object-fit: cover;
      background-color: #eef2f6;
    }

    .card-body {
      padding: 24px;
    }

    .card-title {
      font-size: 20px;
      font-weight: 600;
      color: var(--text-dark);
      margin-bottom: 8px;
    }

    .highlight-number {
      font-size: 36px;
      font-weight: 700;
      color: var(--accent);
      line-height: 1.2;
    }

    /* FAQ 手风琴 */
    .faq-item {
      border-bottom: 1px solid var(--gray-border);
    }
    .faq-question {
      width: 100%;
      background: transparent;
      border: none;
      padding: 20px 0;
      font-size: 18px;
      font-weight: 600;
      color: var(--text-dark);
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      text-align: left;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      font-size: 16px;
      color: var(--text-body);
      padding-bottom: 0;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }

    /* 页脚 */
    .footer {
      background: var(--footer-bg);
      color: #e5e7eb;
      padding: 60px 0 30px;
    }
    .footer a {
      color: #d1d5db;
    }
    .footer a:hover {
      color: white;
    }

    /* 响应式 */
    @media (max-width: 1024px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .grid-3 { grid-template-columns: repeat(2, 1fr); }
      .grid-4 { grid-template-columns: repeat(2, 1fr); }
      section { padding: 80px 0; }
      .section-title { font-size: 28px; }
    }

    @media (max-width: 640px) {
      .container { padding: 0 16px; }
      .grid-3, .grid-4 { grid-template-columns: 1fr; }
      .hero-title { font-size: 32px !important; }
      .btn { padding: 12px 24px; }
      section { padding: 60px 0; }
      .section-title { font-size: 26px; }
    }

    .hero-title {
      font-size: 48px;
      font-weight: 700;
      color: var(--text-dark);
      line-height: 1.25;
    }