/* roulang page: index */
/* ----- 设计变量 ----- */
    :root {
      --primary: #7B2FFF;
      --primary-hover: #6933CC;
      --secondary: #FF6B35;
      --secondary-hover: #E55A2B;
      --bg-dark: #0D0D0D;
      --surface: #1A1A1A;
      --surface-light: #141414;
      --border: #2E2E2E;
      --text-primary: #FFFFFF;
      --text-secondary: #B0B0B0;
      --success: #00E676;
      --danger: #FF1744;
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --shadow-card: 0 8px 20px rgba(0,0,0,0.25);
      --shadow-glow: 0 8px 24px rgba(123,47,255,0.25);
      --shadow-orange: 0 8px 20px rgba(255,107,53,0.25);
      --transition: 0.3s ease;
      --font-system: "PingFang SC", "Microsoft YaHei", "Inter", "Roboto", system-ui, -apple-system, sans-serif;
      --container-max: 1200px;
      --section-gap: 100px;
    }

    /* ----- reset/base ----- */
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; }
    body {
      font-family: var(--font-system);
      background: var(--bg-dark);
      color: var(--text-primary);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    a { text-decoration: none; color: inherit; }
    img { max-width: 100%; height: auto; display: block; }
    button, input, textarea { font-family: inherit; }
    ul, ol { list-style: none; }

    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 20px;
      width: 100%;
    }

    /* 排版 */
    h1, h2, h3, .h1, .h2, .h3 { font-weight: 700; line-height: 1.2; }
    h1 { font-size: 48px; font-weight: 800; }
    h2 { font-size: 36px; }
    h3 { font-size: 24px; font-weight: 600; }
    .text-secondary { color: var(--text-secondary); }
    .text-primary { color: var(--primary); }
    .text-accent { color: var(--secondary); }

    /* 按钮系统 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border-radius: var(--radius-sm);
      font-weight: 600;
      transition: var(--transition);
      cursor: pointer;
      border: none;
      padding: 12px 28px;
      font-size: 16px;
      gap: 8px;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      box-shadow: 0 4px 12px rgba(123,47,255,0.2);
    }
    .btn-primary:hover { background: var(--primary-hover); box-shadow: var(--shadow-glow); transform: translateY(-2px); }
    .btn-cta {
      background: var(--secondary);
      color: white;
      padding: 16px 40px;
      font-weight: 700;
      box-shadow: 0 4px 12px rgba(255,107,53,0.2);
    }
    .btn-cta:hover { background: var(--secondary-hover); box-shadow: var(--shadow-orange); transform: translateY(-2px); }
    .btn-outline {
      background: transparent;
      border: 1px solid var(--primary);
      color: var(--primary);
    }
    .btn-outline:hover { background: rgba(123,47,255,0.1); border-color: var(--primary-hover); color: white; }

    /* 卡片 */
    .card {
      background: var(--surface);
      border: 1px solid var(--border);
      border-radius: var(--radius-md);
      padding: 24px;
      transition: var(--transition);
    }
    .card:hover {
      border-color: var(--primary);
      transform: translateY(-4px);
      box-shadow: 0 12px 24px rgba(123,47,255,0.15);
    }

    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: rgba(13,13,13,0.85);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--border);
      z-index: 1000;
      display: flex;
      align-items: center;
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      font-size: 28px;
      font-weight: 800;
      color: var(--primary);
      letter-spacing: 1px;
      white-space: nowrap;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--text-secondary);
      transition: color 0.2s;
      position: relative;
    }
    .nav-links a:hover, .nav-links a.active {
      color: var(--primary);
    }
    .nav-links a.active::after {
      content: '';
      position: absolute;
      bottom: -8px;
      left: 0;
      width: 100%;
      height: 2px;
      background: var(--primary);
      border-radius: 2px;
    }
    .menu-toggle {
      display: none;
      background: none;
      border: none;
      color: white;
      font-size: 28px;
      cursor: pointer;
    }

    /* Hero */
    .hero {
      min-height: 90vh;
      display: flex;
      align-items: center;
      background: radial-gradient(circle at 30% 50%, rgba(123,47,255,0.08) 0%, transparent 50%);
      position: relative;
      padding-top: 72px;
    }
    .hero-content {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }
    .hero-text h1 {
      text-shadow: 0 0 25px rgba(123,47,255,0.5);
      margin-bottom: 20px;
    }
    .hero-text p {
      font-size: 18px;
      color: var(--text-secondary);
      max-width: 500px;
      margin-bottom: 32px;
    }
    .hero-buttons { display: flex; gap: 16px; flex-wrap: wrap; }
    .hero-visual img {
      border-radius: var(--radius-lg);
      box-shadow: 0 20px 40px rgba(123,47,255,0.15);
      border: 1px solid var(--border);
    }

    /* 数据指示板 */
    .dashboard {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      margin-top: -40px;
      position: relative;
      z-index: 10;
    }
    .stat-card {
      background: var(--surface);
      border-radius: var(--radius-md);
      padding: 28px;
      text-align: center;
    }
    .stat-number {
      font-size: 56px;
      font-weight: 900;
      font-family: 'Inter', sans-serif;
      color: var(--secondary);
      line-height: 1;
    }
    .stat-label { color: var(--text-secondary); margin-top: 8px; }
    .trend-up { color: var(--success); }
    .trend-down { color: var(--danger); }

    /* 服务卡片 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .service-icon {
      width: 64px;
      height: 64px;
      margin-bottom: 20px;
      color: var(--primary);
    }
    .service-card h3 { margin-bottom: 12px; }

    /* 对比表 */
    .comparison-table {
      width: 100%;
      border-collapse: collapse;
      background: var(--surface);
      border-radius: var(--radius-md);
      overflow: hidden;
    }
    .comparison-table th {
      background: var(--primary);
      color: white;
      padding: 16px;
      font-weight: 600;
    }
    .comparison-table td, .comparison-table th {
      padding: 16px;
      border-bottom: 1px solid var(--border);
      text-align: center;
    }
    .highlight-col {
      border-left: 3px solid var(--secondary);
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      background: var(--surface);
      border-radius: var(--radius-sm);
      margin-bottom: 12px;
      border: 1px solid var(--border);
    }
    .faq-question {
      padding: 20px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      font-weight: 600;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      background: var(--surface-light);
      padding: 0 20px;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding: 20px;
    }

    /* 联系表单 */
    .contact-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
      align-items: center;
    }
    .contact-form input, .contact-form textarea {
      width: 100%;
      background: var(--surface);
      border: 1px solid var(--border);
      border-radius: var(--radius-sm);
      padding: 14px;
      color: white;
      margin-bottom: 16px;
      transition: 0.2s;
    }
    .contact-form input:focus, .contact-form textarea:focus {
      border-color: var(--primary);
      outline: none;
    }

    /* 页脚 */
    .footer {
      background: var(--bg-dark);
      border-top: 1px solid var(--border);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }

    @media (max-width: 1024px) {
      h1 { font-size: 40px; }
      .services-grid { grid-template-columns: repeat(2,1fr); }
      .dashboard { grid-template-columns: repeat(2,1fr); }
    }

    @media (max-width: 767px) {
      h1 { font-size: 32px; }
      h2 { font-size: 26px; }
      .container { padding: 0 16px; }
      .nav-links { display: none; position: absolute; top:72px; left:0; width:100%; background:var(--surface); flex-direction:column; padding:20px; }
      .nav-links.active { display: flex; }
      .menu-toggle { display: block; }
      .hero-content { grid-template-columns: 1fr; }
      .dashboard { grid-template-columns: 1fr; }
      .services-grid { grid-template-columns: 1fr; }
      .contact-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
      .comparison-table { display: block; overflow-x: auto; }
    }