/* roulang page: index */
/* 自定义设计变量与全局样式 */
    :root {
      --primary-neon: #8B00FF;
      --accent-cyan: #00F0FF;
      --bg-deep: #0A0E17;
      --bg-card: #111827;
      --bg-card-hover: #1A1F2E;
      --text-primary: #F9FAFB;
      --text-secondary: #B0B8C4;
      --text-muted: #9CA3AF;
      --border-dim: rgba(255,255,255,0.08);
      --border-active: #00F0FF;
      --shadow-glow: 0 0 20px rgba(0,240,255,0.3);
      --radius-md: 12px;
      --radius-sm: 8px;
      --transition-base: all 0.25s ease;
    }

    * {
      box-sizing: border-box;
    }

    body {
      margin: 0;
      font-family: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', system-ui, -apple-system, sans-serif;
      background-color: var(--bg-deep);
      color: var(--text-primary);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      scroll-behavior: smooth;
    }

    .container {
      max-width: 1200px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 20px;
      padding-right: 20px;
    }

    @media (min-width: 768px) {
      .container {
        padding-left: 40px;
        padding-right: 40px;
      }
    }

    /* 霓虹按钮 */
    .btn-primary {
      background: linear-gradient(135deg, #8B00FF 0%, #A020F0 100%);
      color: white;
      border: none;
      padding: 12px 28px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 1rem;
      cursor: pointer;
      transition: var(--transition-base);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      box-shadow: 0 4px 12px rgba(139,0,255,0.3);
      letter-spacing: 0.5px;
    }
    .btn-primary:hover {
      filter: brightness(1.2);
      box-shadow: 0 0 18px rgba(139,0,255,0.7);
      transform: translateY(-2px);
    }

    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--accent-cyan);
      color: var(--accent-cyan);
      padding: 12px 28px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 1rem;
      cursor: pointer;
      transition: var(--transition-base);
      display: inline-flex;
      align-items: center;
      gap: 8px;
    }
    .btn-outline:hover {
      background: rgba(0,240,255,0.1);
      box-shadow: 0 0 14px rgba(0,240,255,0.5);
      transform: translateY(-2px);
    }

    /* 导航 */
    .header-nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 64px;
      background: rgba(10, 14, 23, 0.85);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(255,255,255,0.08);
      z-index: 50;
      display: flex;
      align-items: center;
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      font-size: 1.6rem;
      font-weight: 800;
      letter-spacing: 2px;
      background: linear-gradient(to right, #fff, #e0e0ff);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .logo i {
      background: none;
      -webkit-text-fill-color: var(--accent-cyan);
      font-size: 1.8rem;
    }
    .menu-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .menu-links a {
      color: #CCD0D8;
      text-decoration: none;
      font-size: 0.9rem;
      font-weight: 500;
      transition: color 0.2s;
      position: relative;
    }
    .menu-links a:hover,
    .menu-links a.active {
      color: var(--accent-cyan);
    }
    .menu-links a.active::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 100%;
      height: 2px;
      background: var(--accent-cyan);
    }
    .nav-cta {
      background: var(--primary-neon);
      color: white;
      padding: 8px 20px;
      border-radius: 6px;
      font-size: 0.9rem;
      font-weight: 600;
      text-decoration: none;
      transition: 0.2s;
    }
    .nav-cta:hover {
      box-shadow: 0 0 12px var(--primary-neon);
    }
    .hamburger {
      display: none;
      font-size: 1.8rem;
      color: white;
      background: none;
      border: none;
      cursor: pointer;
    }
    .mobile-menu {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100vh;
      background: rgba(8, 12, 20, 0.96);
      backdrop-filter: blur(20px);
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 40px;
      transform: translateY(-100%);
      transition: 0.35s ease;
      z-index: 45;
    }
    .mobile-menu.open {
      transform: translateY(0);
    }
    .mobile-menu a {
      color: white;
      font-size: 1.5rem;
      font-weight: 600;
      text-decoration: none;
    }
    .close-menu {
      position: absolute;
      top: 20px;
      right: 30px;
      font-size: 2rem;
      background: none;
      border: none;
      color: white;
    }

    @media (max-width: 768px) {
      .menu-links, .nav-cta.desktop-only {
        display: none;
      }
      .hamburger {
        display: block;
      }
    }

    /* 卡片发光效果 */
    .card-glow {
      background: var(--bg-card);
      border: 1px solid var(--border-dim);
      border-radius: var(--radius-md);
      padding: 28px 24px;
      transition: all 0.3s ease;
    }
    .card-glow:hover {
      border-color: var(--accent-cyan);
      box-shadow: 0 0 24px rgba(0,240,255,0.25);
      transform: translateY(-6px);
      background: #1A1F2E;
    }

    .price-card-highlight {
      border: 2px solid var(--primary-neon);
      box-shadow: 0 0 22px rgba(139,0,255,0.45);
      transform: scale(1.03);
    }

    .faq-item {
      background: #1A1F2E;
      border-radius: 10px;
      margin-bottom: 12px;
      overflow: hidden;
    }
    .faq-question {
      padding: 18px 24px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      background: #222838;
      color: #B0B8C4;
      padding: 0 24px;
      border-left: 3px solid var(--accent-cyan);
    }
    .faq-answer.open {
      max-height: 160px;
      padding: 16px 24px;
    }

    footer {
      background: #060A10;
      color: #9CA3AF;
    }
    .social-icon {
      color: #6B7280;
      transition: 0.2s;
      font-size: 1.4rem;
    }
    .social-icon:hover {
      color: var(--accent-cyan);
    }