/* roulang page: index */
/* 自定义 CSS 变量与全局重置 */
    :root {
      --bg-primary: #0B0A1A;
      --bg-card: rgba(26, 26, 46, 0.7);
      --text-primary: #F5F3FF;
      --text-secondary: #B0AEC6;
      --accent-purple: #A855F7;
      --accent-cyan: #22D3EE;
      --glass-blur: blur(18px);
      --border-glass: rgba(255, 255, 255, 0.08);
      --glow-purple: 0 0 18px rgba(168, 85, 247, 0.5);
      --glow-cyan: 0 0 18px rgba(34, 211, 238, 0.45);
      --radius-card: 20px;
      --radius-btn: 10px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Inter", system-ui, -apple-system, sans-serif;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-primary);
      color: var(--text-primary);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      scroll-behavior: smooth;
    }

    /* 背景纹理网格（极淡） */
    body::before {
      content: "";
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background-image: 
        linear-gradient(rgba(168, 85, 247, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(34, 211, 238, 0.02) 1px, transparent 1px);
      background-size: 50px 50px;
      pointer-events: none;
      z-index: -1;
    }

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }

    @media (max-width: 768px) {
      .container {
        padding: 0 16px;
      }
    }

    /* 玻璃拟态卡片基础 */
    .glass-card {
      background: rgba(26, 26, 46, 0.55);
      backdrop-filter: var(--glass-blur);
      -webkit-backdrop-filter: var(--glass-blur);
      border: 1px solid var(--border-glass);
      border-radius: var(--radius-card);
      box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4);
      transition: all 0.3s ease;
    }

    .glass-card:hover {
      border-color: rgba(168, 85, 247, 0.25);
      box-shadow: 0 12px 28px rgba(0, 0, 0, 0.6), 0 0 15px rgba(168, 85, 247, 0.15);
      transform: translateY(-4px);
    }

    /* 按钮样式 */
    .btn-primary {
      background: linear-gradient(135deg, #A855F7 0%, #7C3AED 100%);
      color: white;
      font-weight: 600;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      transition: all 0.3s ease;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      letter-spacing: 0.5px;
      border: 1px solid transparent;
      box-shadow: 0 4px 14px rgba(168, 85, 247, 0.4);
    }

    .btn-primary:hover {
      background: linear-gradient(135deg, #B36AF9 0%, #8B4FEF 100%);
      border-color: var(--accent-cyan);
      box-shadow: var(--glow-purple), 0 0 22px rgba(34, 211, 238, 0.4);
      transform: scale(1.02);
    }

    .btn-ghost {
      background: transparent;
      border: 1px solid rgba(34, 211, 238, 0.5);
      color: var(--accent-cyan);
      font-weight: 600;
      padding: 12px 32px;
      border-radius: var(--radius-btn);
      transition: all 0.3s ease;
      backdrop-filter: blur(8px);
    }

    .btn-ghost:hover {
      background: rgba(34, 211, 238, 0.08);
      border-color: var(--accent-cyan);
      box-shadow: 0 0 16px rgba(34, 211, 238, 0.5);
    }

    /* 导航栏固定 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: rgba(11, 10, 26, 0.8);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-bottom: 1px solid rgba(255, 255, 255, 0.06);
      z-index: 100;
      display: flex;
      align-items: center;
    }

    /* 分段标签导航 chip/tab */
    .nav-chip {
      padding: 8px 20px;
      border-radius: 40px;
      font-size: 0.95rem;
      font-weight: 500;
      transition: all 0.3s ease;
      border: 1px solid transparent;
      background: transparent;
      color: var(--text-secondary);
      cursor: pointer;
    }

    .nav-chip.active {
      background: var(--accent-purple);
      color: white;
      border-color: var(--accent-purple);
      box-shadow: 0 0 12px rgba(168, 85, 247, 0.6);
    }

    .nav-chip:not(.active):hover {
      border-color: rgba(168, 85, 247, 0.4);
      color: var(--text-primary);
      background: rgba(168, 85, 247, 0.08);
    }

    /* 移动端菜单 */
    .mobile-menu {
      transition: transform 0.3s ease;
    }

    @media (max-width: 768px) {
      .mobile-hidden {
        display: none;
      }
      .mobile-menu.open {
        transform: translateX(0);
      }
    }

    /* Hero 背景动画占位 */
    .hero-bg-animate {
      background: radial-gradient(circle at 30% 40%, rgba(168, 85, 247, 0.15) 0%, transparent 50%),
                  radial-gradient(circle at 70% 60%, rgba(34, 211, 238, 0.1) 0%, transparent 50%);
      position: absolute;
      inset: 0;
      z-index: 0;
    }

    /* 数字跳动暗示动画 */
    @keyframes subtlePulse {
      0% { opacity: 0.9; transform: scale(1); }
      50% { opacity: 1; transform: scale(1.02); }
      100% { opacity: 0.9; transform: scale(1); }
    }
    .stat-number {
      animation: subtlePulse 2s infinite ease-in-out;
    }

    /* FAQ 手风琴 */
    .faq-item {
      border-bottom: 1px solid rgba(255,255,255,0.06);
    }
    .faq-question {
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 20px 0;
      font-weight: 600;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.3s ease;
      color: var(--text-secondary);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }
    .faq-icon {
      transition: transform 0.3s ease;
      color: var(--accent-cyan);
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }