/* roulang page: index */
:root {
      --deep-space: #0A0E27;
      --card-bg: #111640;
      --secondary-bg: #1A1F4E;
      --electric-cyan: #00F0FF;
      --magenta-pink: #FF3CAC;
      --white: #FFFFFF;
      --text-light: #B0C4DE;
      --text-muted: #6B7280;
      --border-subtle: rgba(0, 240, 255, 0.15);
      --radius-card: 12px;
      --shadow-glow: 0 0 20px rgba(0, 240, 255, 0.3);
      --font-mono: 'JetBrains Mono', monospace;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
      --nav-height: 72px;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--deep-space);
      color: var(--text-light);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
      background-image: 
        linear-gradient(rgba(0, 240, 255, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 240, 255, 0.03) 1px, transparent 1px);
      background-size: 40px 40px;
    }

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

    a {
      color: inherit;
      text-decoration: none;
    }

    button, input, textarea {
      font-family: inherit;
      outline: none;
    }

    .container {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }

    /* 导航 */
    #main-nav {
      position: sticky;
      top: 0;
      z-index: 50;
      background-color: rgba(10, 14, 39, 0.9);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-subtle);
      height: var(--nav-height);
      display: flex;
      align-items: center;
    }

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

    .logo {
      font-size: 1.8rem;
      font-weight: 800;
      color: var(--white);
      letter-spacing: 1px;
      position: relative;
      display: inline-block;
    }
    .logo::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 100%;
      height: 3px;
      background: var(--electric-cyan);
      box-shadow: 0 0 12px var(--electric-cyan);
    }

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

    .nav-links a {
      font-weight: 500;
      color: var(--text-light);
      transition: color 0.2s, border-bottom 0.2s;
      padding-bottom: 6px;
      border-bottom: 2px solid transparent;
      font-size: 1rem;
    }

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

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 6px;
      background: none;
      border: none;
      cursor: pointer;
    }
    .hamburger span {
      width: 28px;
      height: 3px;
      background: var(--white);
      border-radius: 2px;
      transition: 0.3s;
    }

    /* 按钮 */
    .btn-primary {
      background: var(--magenta-pink);
      color: white;
      font-weight: 700;
      padding: 0.85rem 2rem;
      border-radius: 40px;
      border: none;
      cursor: pointer;
      transition: background 0.25s, box-shadow 0.25s, transform 0.15s;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      box-shadow: 0 4px 14px rgba(255, 60, 172, 0.4);
      letter-spacing: 0.5px;
    }
    .btn-primary:hover {
      background: #ff5cbf;
      box-shadow: 0 8px 22px rgba(255, 60, 172, 0.6);
      transform: translateY(-2px);
    }

    .btn-outline {
      background: transparent;
      border: 2px solid var(--electric-cyan);
      color: var(--electric-cyan);
      font-weight: 700;
      padding: 0.8rem 2rem;
      border-radius: 40px;
      transition: all 0.25s;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      letter-spacing: 0.5px;
    }
    .btn-outline:hover {
      background: rgba(0, 240, 255, 0.08);
      box-shadow: 0 0 18px rgba(0, 240, 255, 0.4);
    }

    /* 卡片 */
    .card {
      background: var(--card-bg);
      border: 1px solid var(--border-subtle);
      border-radius: var(--radius-card);
      padding: 1.8rem;
      transition: all 0.3s ease;
    }
    .card:hover {
      border-color: var(--electric-cyan);
      box-shadow: var(--shadow-glow);
    }

    .stat-number {
      font-family: var(--font-mono);
      font-weight: 800;
      color: var(--electric-cyan);
    }

    .section-title {
      font-size: 2rem;
      font-weight: 800;
      color: var(--white);
      margin-bottom: 2.5rem;
      display: flex;
      align-items: center;
      gap: 1rem;
    }
    .section-title::before {
      content: '';
      width: 6px;
      height: 36px;
      background: var(--electric-cyan);
      box-shadow: 0 0 15px var(--electric-cyan);
      border-radius: 3px;
    }

    /* FAQ */
    .faq-item {
      border: 1px solid var(--border-subtle);
      border-radius: var(--radius-card);
      background: var(--card-bg);
      margin-bottom: 1rem;
      overflow: hidden;
      transition: all 0.2s;
    }
    .faq-item.active {
      border-color: var(--electric-cyan);
      background: #1A1F4E;
    }
    .faq-question {
      width: 100%;
      background: transparent;
      border: none;
      color: var(--white);
      font-weight: 700;
      font-size: 1.1rem;
      padding: 1.3rem 1.8rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
    }
    .faq-answer {
      padding: 0 1.8rem 1.5rem;
      color: var(--text-light);
      display: none;
    }
    .faq-item.active .faq-answer {
      display: block;
    }

    footer {
      background: var(--deep-space);
      border-top: 1px solid var(--border-subtle);
      padding: 3rem 0 2rem;
      color: var(--text-muted);
    }

    @media (max-width: 768px) {
      .nav-links {
        display: none;
        position: absolute;
        top: var(--nav-height);
        left: 0;
        width: 100%;
        background: rgba(10, 14, 39, 0.98);
        backdrop-filter: blur(18px);
        flex-direction: column;
        padding: 2rem;
        gap: 1.8rem;
        border-bottom: 1px solid var(--border-subtle);
      }
      .nav-links.open {
        display: flex;
      }
      .hamburger {
        display: flex;
      }
      .section-title {
        font-size: 1.8rem;
      }
    }