/* roulang page: index */
/* 自定义CSS变量与全局样式 */
    :root {
      --primary-cyan: #00F5D4;
      --accent-red: #E63946;
      --energy-orange: #FF6B35;
      --bg-deep: #0B0E14;
      --card-bg: rgba(26, 31, 43, 0.75);
      --card-border: rgba(0, 245, 212, 0.18);
      --text-ice: #E0E6ED;
      --text-dim: rgba(224, 230, 237, 0.7);
      --glass-blur: blur(14px);
      --radius-card: 16px;
      --radius-btn: 10px;
      --shadow-glow: 0 0 18px rgba(0, 245, 212, 0.35);
      --transition-smooth: all 0.25s ease;
    }
    * {
      box-sizing: border-box;
    }
    body {
      margin: 0;
      font-family: 'Inter', system-ui, -apple-system, 'Microsoft YaHei', sans-serif;
      background-color: var(--bg-deep);
      color: var(--text-ice);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    button, input, textarea {
      font-family: inherit;
    }
    .container {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 24px;
      padding-right: 24px;
    }
    /* 玻璃拟态卡片 */
    .glass-card {
      background: var(--card-bg);
      backdrop-filter: var(--glass-blur);
      -webkit-backdrop-filter: var(--glass-blur);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-card);
      box-shadow: 0 10px 28px -8px rgba(0,0,0,0.5);
    }
    /* 发光按钮 */
    .btn-glow {
      background: var(--primary-cyan);
      color: #0B0E14;
      font-weight: 700;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      border: none;
      cursor: pointer;
      transition: var(--transition-smooth);
      box-shadow: 0 4px 14px rgba(0,245,212,0.3);
      letter-spacing: 0.5px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }
    .btn-glow:hover {
      box-shadow: 0 0 24px rgba(0,245,212,0.7), 0 8px 20px rgba(0,0,0,0.5);
      transform: translateY(-2px);
    }
    .btn-ghost {
      background: transparent;
      border: 1.5px solid var(--primary-cyan);
      color: var(--primary-cyan);
      font-weight: 600;
      padding: 13px 30px;
      border-radius: var(--radius-btn);
      cursor: pointer;
      transition: var(--transition-smooth);
      backdrop-filter: blur(8px);
    }
    .btn-ghost:hover {
      background: rgba(0,245,212,0.1);
      box-shadow: 0 0 18px rgba(0,245,212,0.4);
      border-color: #00f5d4;
    }
    /* 区块标题装饰线 */
    .section-title {
      font-size: 2rem;
      font-weight: 700;
      letter-spacing: -0.3px;
      display: flex;
      align-items: center;
      gap: 12px;
      margin-bottom: 2.5rem;
    }
    .section-title::before {
      content: '';
      display: inline-block;
      width: 6px;
      height: 28px;
      background: var(--primary-cyan);
      border-radius: 4px;
      box-shadow: 0 0 12px var(--primary-cyan);
    }
    .metric-number {
      font-family: 'JetBrains Mono', monospace;
      font-weight: 800;
      font-size: 3rem;
      color: var(--primary-cyan);
      text-shadow: 0 0 14px rgba(0,245,212,0.5);
    }
    /* 导航激活条 */
    .nav-link {
      position: relative;
      font-weight: 500;
      transition: color 0.2s;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -6px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--primary-cyan);
      box-shadow: 0 0 8px var(--primary-cyan);
      transition: width 0.3s ease;
    }
    .nav-link:hover::after,
    .nav-link.active::after {
      width: 100%;
    }
    /* FAQ手风琴效果 */
    .faq-item {
      border-left: 3px solid transparent;
      transition: border 0.2s, background 0.2s;
    }
    .faq-item.active {
      border-left-color: var(--primary-cyan);
      background: rgba(0,245,212,0.05);
    }
    /* 移动端菜单 */
    .mobile-menu {
      display: none;
      flex-direction: column;
      background: rgba(11,14,20,0.96);
      backdrop-filter: blur(24px);
      position: absolute;
      top: 64px;
      left: 0;
      width: 100%;
      padding: 20px;
      border-bottom: 1px solid var(--primary-cyan);
    }
    @media (max-width: 768px) {
      .container {
        padding-left: 20px;
        padding-right: 20px;
      }
      .section-title {
        font-size: 1.7rem;
      }
      .metric-number {
        font-size: 2.4rem;
      }
    }