/* roulang page: index */
:root {
      --bg-dark: #070B19;
      --card-bg: rgba(15, 23, 42, 0.72);
      --card-border: rgba(59, 130, 246, 0.22);
      --card-border-hover: rgba(6, 182, 212, 0.55);
      --text-main: #F8FAFC;
      --text-muted: #94A3B8;
      --glow-blue: 0 0 25px rgba(37, 99, 235, 0.45);
      --glow-cyan: 0 0 25px rgba(6, 182, 212, 0.5);
    }

    body {
      background-color: var(--bg-dark);
      color: #94A3B8;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      overflow-x: hidden;
      line-height: 1.65;
    }

    .glass-card {
      background: var(--card-bg);
      backdrop-filter: blur(16px);
      -webkit-backdrop-filter: blur(16px);
      border: 1px solid var(--card-border);
      box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }

    .glass-card:hover {
      border-color: var(--card-border-hover);
      transform: translateY(-4px);
      box-shadow: 0 16px 40px -10px rgba(6, 182, 212, 0.25);
    }

    .btn-glow {
      background: linear-gradient(135deg, #06B6D4 0%, #2563EB 100%);
      box-shadow: var(--glow-cyan);
      transition: all 0.3s ease;
    }

    .btn-glow:hover {
      box-shadow: 0 0 35px rgba(6, 182, 212, 0.75);
      transform: translateY(-2px);
    }

    .btn-outline-glow {
      background: rgba(13, 21, 45, 0.6);
      border: 1.5px solid rgba(59, 130, 246, 0.5);
      box-shadow: 0 0 15px rgba(37, 99, 235, 0.2);
      transition: all 0.3s ease;
    }

    .btn-outline-glow:hover {
      border-color: #06B6D4;
      background: rgba(37, 99, 235, 0.18);
      box-shadow: 0 0 25px rgba(6, 182, 212, 0.4);
      transform: translateY(-2px);
    }

    .tech-grid-bg {
      background-image: radial-gradient(rgba(59, 130, 246, 0.12) 1px, transparent 1px);
      background-size: 32px 32px;
    }

    .gradient-text {
      background: linear-gradient(135deg, #FFFFFF 20%, #93C5FD 70%, #06B6D4 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    /* 手风琴平滑展开与旋转 */
    .faq-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease-out, padding 0.35s ease;
    }
    .faq-item.active .faq-content {
      max-height: 280px;
    }
    .faq-item.active .faq-icon {
      transform: rotate(180deg);
      color: #06B6D4;
    }
    .faq-item.active {
      border-color: rgba(6, 182, 212, 0.5);
      background: rgba(15, 23, 42, 0.85);
    }

    input:focus, select:focus, textarea:focus {
      outline: none;
      box-shadow: 0 0 0 2px #06B6D4, 0 0 20px rgba(6, 182, 212, 0.35);
      border-color: #06B6D4;
    }