/* roulang page: index */
:root {
      --primary: #d4af37;
      --primary-glow: #fbbf24;
      --secondary: #0f172a;
      --accent: #c026d3;
      --dark-bg: #020617;
      --card-bg: #0f172ab3;
      --text: #f1f5f9;
      --text-muted: #94a3b8;
      --border: #334155;
      --radius-lg: 1.5rem;
      --radius-md: 1rem;
      --shadow-glow: 0 8px 32px rgba(212, 175, 55, 0.25);
      --shadow-card: 0 20px 40px rgba(0, 0, 0, 0.6);
      --neon-line: #d4af37;
    }

    * {
      box-sizing: border-box;
    }

    body {
      margin: 0;
      font-family: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
      background-color: var(--dark-bg);
      color: var(--text);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }

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

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

    button, input {
      font-family: inherit;
    }

    /* 自定义滚动条 */
    ::-webkit-scrollbar {
      width: 6px;
    }
    ::-webkit-scrollbar-track {
      background: #0f172a;
    }
    ::-webkit-scrollbar-thumb {
      background: #d4af37;
      border-radius: 8px;
    }

    /* 导航发光效果 */
    .nav-link {
      position: relative;
      transition: color 0.2s ease;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: -4px;
      width: 0%;
      height: 2px;
      background: var(--neon-line);
      box-shadow: 0 0 12px var(--primary-glow);
      transition: width 0.3s ease;
    }
    .nav-link:hover::after,
    .nav-link.active::after {
      width: 100%;
    }
    .nav-link.active {
      color: var(--primary);
    }

    /* 卡片悬停 */
    .feature-card {
      transition: transform 0.25s ease, box-shadow 0.3s ease, border-color 0.2s;
    }
    .feature-card:hover {
      transform: translateY(-8px);
      box-shadow: var(--shadow-glow);
      border-color: var(--primary);
    }

    /* 按钮辉光 */
    .btn-primary {
      background: linear-gradient(135deg, #d4af37 0%, #fbbf24 100%);
      border: none;
      color: #0f172a;
      font-weight: 700;
      padding: 0.75rem 2rem;
      border-radius: 2rem;
      box-shadow: 0 4px 18px rgba(212, 175, 55, 0.5);
      transition: all 0.25s;
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }
    .btn-primary:hover {
      box-shadow: 0 10px 28px rgba(251, 191, 36, 0.7);
      transform: scale(1.02);
      color: #000;
    }

    .btn-outline-neon {
      border: 1px solid var(--primary);
      background: transparent;
      color: var(--primary);
      padding: 0.65rem 2rem;
      border-radius: 2rem;
      transition: all 0.25s;
    }
    .btn-outline-neon:hover {
      background: var(--primary);
      color: #020617;
      box-shadow: 0 0 20px var(--primary-glow);
    }

    /* 背景叠加 */
    .hero-backdrop {
      background: radial-gradient(circle at 20% 20%, rgba(212, 175, 55, 0.15) 0%, transparent 50%);
    }

    /* FAQ 手风琴效果 */
    .faq-item {
      border-bottom: 1px solid var(--border);
    }
    .faq-question {
      cursor: pointer;
      transition: color 0.2s;
    }
    .faq-question:hover {
      color: var(--primary);
    }

    @media (max-width: 768px) {
      .mobile-menu {
        display: none;
      }
      .mobile-menu.open {
        display: flex;
        flex-direction: column;
        background: #0f172af0;
        backdrop-filter: blur(12px);
        position: absolute;
        top: 70px;
        left: 0;
        width: 100%;
        padding: 1.5rem;
        gap: 1.2rem;
        border-bottom: 2px solid var(--primary);
      }
    }