/* roulang page: index */
* {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    :root {
      --primary: #6C3CF0;
      --primary-glow: rgba(108, 60, 240, 0.6);
      --secondary: #00F0FF;
      --secondary-glow: rgba(0, 240, 255, 0.3);
      --bg-deep: #0A0E17;
      --bg-card: #141A26;
      --text-primary: #FFFFFF;
      --text-secondary: #B0B8C8;
      --text-muted: #6B7280;
      --border-dim: rgba(0, 240, 255, 0.15);
      --border-active: #00F0FF;
      --radius-lg: 16px;
      --radius-md: 12px;
      --radius-btn: 8px;
      --shadow-card: 0 12px 30px rgba(0, 0, 0, 0.5);
      --shadow-hover: 0 15px 25px rgba(0, 240, 255, 0.15);
      --transition-base: all 0.3s cubic-bezier(0.2, 0.8, 0.4, 1);
    }
    body {
      background-color: var(--bg-deep);
      font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      color: var(--text-secondary);
      line-height: 1.75;
      font-weight: 400;
      letter-spacing: 0.01em;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: 1280px;
      width: 100%;
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航栏 玻璃态固定头 */
    header.nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 50;
      background: rgba(10, 14, 23, 0.75);
      backdrop-filter: blur(14px);
      -webkit-backdrop-filter: blur(14px);
      border-bottom: 1px solid rgba(0, 240, 255, 0.15);
      transition: background 0.4s;
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-size: 1.5rem;
      font-weight: 700;
      color: var(--text-primary);
      text-decoration: none;
      letter-spacing: -0.02em;
    }
    .logo i {
      color: var(--secondary);
      font-size: 1.8rem;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 28px;
    }
    .nav-links a {
      color: var(--text-secondary);
      text-decoration: none;
      font-weight: 500;
      position: relative;
      transition: color 0.2s;
      font-size: 0.95rem;
    }
    .nav-links a:hover, .nav-links a.active {
      color: var(--secondary);
    }
    .btn-nav {
      background: var(--primary);
      color: white;
      padding: 10px 22px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: var(--transition-base);
      text-decoration: none;
      box-shadow: 0 4px 14px rgba(108,60,240,0.4);
    }
    .btn-nav:hover {
      background: #8450ff;
      box-shadow: 0 0 22px var(--primary-glow);
    }
    .mobile-toggle {
      display: none;
      background: transparent;
      border: none;
      color: var(--text-primary);
      font-size: 1.8rem;
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .mobile-toggle { display: block; }
      .nav-container { height: 64px; }
    }
    /* 通用板块 */
    section {
      padding: 120px 0;
    }
    @media (max-width: 768px) {
      section { padding: 80px 0; }
    }
    h2 {
      font-size: 2.6rem;
      font-weight: 700;
      letter-spacing: -0.02em;
      color: var(--text-primary);
      margin-bottom: 16px;
    }
    h3 {
      font-size: 1.6rem;
      font-weight: 600;
      color: var(--text-primary);
      margin-bottom: 12px;
    }
    /* 按钮系统 */
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      text-decoration: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      border: none;
      box-shadow: 0 8px 20px rgba(108,60,240,0.5);
      transition: var(--transition-base);
      letter-spacing: 0.3px;
    }
    .btn-primary:hover {
      background: #8458ff;
      box-shadow: 0 0 28px var(--primary-glow);
      transform: translateY(-2px);
    }
    .btn-outline {
      background: transparent;
      border: 1px solid var(--secondary);
      color: var(--secondary);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      text-decoration: none;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      transition: var(--transition-base);
    }
    .btn-outline:hover {
      background: var(--secondary);
      color: #0A0E17;
      box-shadow: 0 0 18px var(--secondary-glow);
    }
    /* 卡片通用 */
    .card {
      background: var(--bg-card);
      border: 1px solid var(--border-dim);
      border-radius: var(--radius-md);
      padding: 28px;
      transition: var(--transition-base);
    }
    .card:hover {
      transform: translateY(-6px);
      border-color: var(--border-active);
      box-shadow: var(--shadow-hover);
    }