/* roulang page: index */
:root {
      --bg-deep: #0B0E14;
      --cyan: #00F0FF;
      --purple: #B44CFF;
      --card-bg: rgba(20, 24, 34, 0.8);
      --border-glow: rgba(0, 240, 255, 0.25);
      --text-dim: #9CA3AF;
      --section-gap: 5rem;
      --card-radius: 12px;
      --shadow-neon: 0 8px 32px rgba(0,0,0,0.6);
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Inter", sans-serif;
      background-color: var(--bg-deep);
      color: #e5e7eb;
      line-height: 1.6;
      margin: 0;
      overflow-x: hidden;
    }
    /* 网格背景 */
    .grid-bg {
      background-image: 
        linear-gradient(rgba(0, 240, 255, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 240, 255, 0.03) 1px, transparent 1px);
      background-size: 40px 40px;
      background-position: center center;
    }
    /* 玻璃拟态卡片 */
    .glass-card {
      background: var(--card-bg);
      backdrop-filter: blur(12px);
      border: 1px solid var(--border-glow);
      border-radius: var(--card-radius);
      box-shadow: var(--shadow-neon);
      transition: all 0.25s ease;
    }
    .glass-card:hover {
      border-color: rgba(0, 240, 255, 0.5);
      box-shadow: 0 12px 36px rgba(0, 240, 255, 0.2);
      transform: translateY(-4px);
    }
    /* 霓虹按钮 */
    .btn-primary {
      background: linear-gradient(135deg, #00F0FF 0%, #B44CFF 100%);
      border: none;
      color: white;
      font-weight: 600;
      padding: 0.8rem 2rem;
      border-radius: 8px;
      transition: all 0.3s ease;
      box-shadow: 0 4px 15px rgba(0, 240, 255, 0.3);
      letter-spacing: 0.5px;
    }
    .btn-primary:hover {
      filter: brightness(1.2);
      box-shadow: 0 0 25px rgba(0, 240, 255, 0.6);
      transform: translateY(-2px);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid #00F0FF;
      color: #00F0FF;
      font-weight: 600;
      padding: 0.8rem 2rem;
      border-radius: 8px;
      transition: all 0.3s ease;
    }
    .btn-outline:hover {
      background: rgba(0, 240, 255, 0.1);
      box-shadow: 0 0 20px rgba(0, 240, 255, 0.4);
    }
    /* 导航下划线动画 */
    .nav-link {
      position: relative;
      padding-bottom: 4px;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      width: 0;
      height: 2px;
      bottom: 0;
      left: 50%;
      background: #00F0FF;
      transition: all 0.3s ease;
      transform: translateX(-50%);
    }
    .nav-link:hover::after {
      width: 100%;
    }
    /* 数据看板装饰 */
    .progress-ring {
      stroke-dasharray: 251.2;
      stroke-dashoffset: 50;
      stroke: #00F0FF;
      filter: drop-shadow(0 0 6px #00F0FF);
    }
    /* FAQ 折叠动画模拟 */
    .faq-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
    }
    .faq-item.active .faq-content {
      max-height: 200px;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    /* 输入框底部线条 */
    .input-line {
      background: transparent;
      border: none;
      border-bottom: 1.5px solid #4B5563;
      border-radius: 0;
      padding: 0.8rem 0.5rem;
      color: white;
      transition: border-color 0.3s, box-shadow 0.3s;
      width: 100%;
    }
    .input-line:focus {
      outline: none;
      border-bottom-color: #00F0FF;
      box-shadow: 0 4px 12px -6px #00F0FF;
    }
    /* 扫描线按钮动画 */
    .btn-scan:hover {
      background: linear-gradient(135deg, #00F0FF 0%, #B44CFF 100%);
      position: relative;
      overflow: hidden;
    }
    .btn-scan:hover::after {
      content: "";
      position: absolute;
      top: 0;
      left: -100%;
      width: 100%;
      height: 100%;
      background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
      transition: left 0.5s;
      left: 100%;
    }
    @media (max-width: 768px) {
      :root {
        --section-gap: 3.5rem;
      }
    }