/* roulang page: index */
:root {
      --primary-bg: #0D0B1E;
      --card-bg: rgba(26, 21, 48, 0.6);
      --glass-border: rgba(0, 240, 255, 0.15);
      --cyan: #00F0FF;
      --magenta: #FF006E;
      --text-primary: #E0E0E0;
      --text-secondary: #A0A0B0;
      --dark-surface: #1A1530;
      --deep-dark: #05030F;
      --radius-card: 16px;
      --radius-btn: 8px;
      --shadow-glow: 0 0 20px rgba(0, 240, 255, 0.4);
      --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.4);
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
      --font-mono: 'Inter', 'Roboto', sans-serif;
    }
    * {
      box-sizing: border-box;
    }
    body {
      margin: 0;
      font-family: var(--font-sans);
      background-color: var(--primary-bg);
      color: var(--text-primary);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 20px;
      padding-right: 20px;
    }
    /* 玻璃拟态卡片 */
    .glass-card {
      background: var(--card-bg);
      backdrop-filter: blur(12px);
      border: 1px solid var(--glass-border);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
    }
    /* 导航发光下划线 */
    .nav-link {
      position: relative;
      transition: color 0.2s;
      color: #E0E0E0;
      font-weight: 500;
    }
    .nav-link:hover {
      color: var(--cyan);
    }
    .nav-link::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: -4px;
      width: 0%;
      height: 2px;
      background: var(--cyan);
      box-shadow: 0 0 8px var(--cyan);
      transition: width 0.25s ease;
    }
    .nav-link:hover::after {
      width: 100%;
    }
    /* 按钮体系 */
    .btn-primary {
      background: var(--cyan);
      color: #0D0B1E;
      font-weight: 700;
      border-radius: var(--radius-btn);
      padding: 14px 32px;
      box-shadow: var(--shadow-glow);
      transition: all 0.25s;
      display: inline-block;
      text-align: center;
      border: none;
      cursor: pointer;
    }
    .btn-primary:hover {
      box-shadow: 0 0 30px rgba(0, 240, 255, 0.7);
      transform: translateY(-2px);
    }
    .btn-secondary {
      background: transparent;
      color: var(--cyan);
      border: 2px solid var(--cyan);
      font-weight: 600;
      border-radius: var(--radius-btn);
      padding: 14px 32px;
      transition: all 0.25s;
      display: inline-block;
      text-align: center;
      cursor: pointer;
    }
    .btn-secondary:hover {
      background: rgba(0, 240, 255, 0.1);
      transform: translateY(-2px);
    }
    /* 发光数字 */
    .glow-number {
      font-family: var(--font-mono);
      font-weight: 700;
      font-size: 56px;
      color: var(--cyan);
      text-shadow: 0 0 15px rgba(0, 240, 255, 0.6);
      line-height: 1.2;
    }
    /* 手风琴动画 */
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
    }
    .faq-icon {
      transition: transform 0.2s;
    }
    .faq-item.open .faq-icon {
      transform: rotate(180deg);
    }
    /* 装饰分割线 */
    .section-divider {
      width: 60px;
      height: 3px;
      background: linear-gradient(90deg, var(--cyan), var(--magenta));
      margin: 12px auto 32px;
      border-radius: 2px;
    }
    /* 移动端菜单 */
    @media (max-width: 768px) {
      .desktop-nav {
        display: none;
      }
      .mobile-menu-btn {
        display: block;
      }
      #mobileMenu {
        display: none;
        flex-direction: column;
        background: rgba(13, 11, 30, 0.95);
        backdrop-filter: blur(12px);
        position: absolute;
        top: 72px;
        left: 0;
        right: 0;
        padding: 20px;
        gap: 16px;
        border-bottom: 1px solid var(--glass-border);
      }
      #mobileMenu.active {
        display: flex;
      }
    }
    @media (min-width: 769px) {
      .mobile-menu-btn {
        display: none;
      }
      #mobileMenu {
        display: none;
      }
      .desktop-nav {
        display: flex;
      }
    }
    /* 背景纹理 */
    .hero-bg {
      background-image: radial-gradient(rgba(0,240,255,0.05) 1px, transparent 1px);
      background-size: 40px 40px;
    }
    .cta-banner {
      background: linear-gradient(135deg, #00F0FF 0%, #FF006E 100%);
      position: relative;
      overflow: hidden;
    }
    .cta-banner::after {
      content: '';
      position: absolute;
      inset: 0;
      background-image: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="100" height="100" viewBox="0 0 100 100"><circle cx="15" cy="20" r="1.5" fill="white" opacity="0.15"/><circle cx="85" cy="75" r="1" fill="white" opacity="0.1"/></svg>');
      pointer-events: none;
    }