/* roulang page: index */
:root {
      --primary: #00F0FF;
      --accent: #FF006E;
      --deep-purple: #7000FF;
      --bg-deep: #0A0E1A;
      --card-bg: rgba(10, 14, 26, 0.6);
      --card-border: rgba(0, 240, 255, 0.15);
      --text-body: #B0C4DE;
      --text-muted: #6B7B8D;
      --white: #FFFFFF;
      --radius-card: 16px;
      --radius-btn: 8px;
    }

    * {
      box-sizing: border-box;
    }

    body {
      margin: 0;
      font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--bg-deep);
      color: var(--text-body);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }

    .data-font {
      font-family: "Inter", "SF Mono", "Menlo", monospace;
    }

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

    .glass-card:hover {
      border-color: rgba(0, 240, 255, 0.4);
      box-shadow: 0 8px 32px rgba(0, 240, 255, 0.12);
      transform: translateY(-4px);
    }

    .btn-primary {
      background: linear-gradient(135deg, #00F0FF, #7000FF);
      color: white;
      border: none;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      box-shadow: 0 0 20px rgba(0, 240, 255, 0.5);
      transition: all 0.3s ease;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
    }

    .btn-primary:hover {
      box-shadow: 0 0 35px rgba(0, 240, 255, 0.8);
      transform: translateY(-2px);
    }

    .btn-ghost {
      background: transparent;
      border: 1px solid rgba(0, 240, 255, 0.5);
      color: #00F0FF;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: all 0.3s ease;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
    }

    .btn-ghost:hover {
      border-color: #00F0FF;
      background: rgba(0, 240, 255, 0.08);
      box-shadow: 0 0 15px rgba(0, 240, 255, 0.25);
    }

    .section-spacing {
      padding: 120px 0;
    }

    @media (max-width: 768px) {
      .section-spacing {
        padding: 80px 0;
      }
      h1 {
        font-size: 36px !important;
        line-height: 1.3 !important;
      }
      h2 {
        font-size: 30px !important;
      }
    }

    .glow-text {
      background: linear-gradient(135deg, #00F0FF, #FF006E);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }

    .nav-blur {
      background: rgba(10, 14, 26, 0.75);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(0, 240, 255, 0.2);
    }

    .breathing-light {
      animation: breathe 2.5s infinite ease-in-out;
    }

    @keyframes breathe {
      0% { box-shadow: 0 0 18px rgba(0, 240, 255, 0.4); }
      50% { box-shadow: 0 0 30px rgba(0, 240, 255, 0.8); }
      100% { box-shadow: 0 0 18px rgba(0, 240, 255, 0.4); }
    }

    .float-animation {
      animation: float 3.5s infinite ease-in-out;
    }
    .float-delay-1 { animation-delay: 0s; }
    .float-delay-2 { animation-delay: 1.2s; }
    .float-delay-3 { animation-delay: 2.4s; }

    @keyframes float {
      0% { transform: translateY(0px); }
      50% { transform: translateY(-12px); }
      100% { transform: translateY(0px); }
    }

    .hero-card-stack {
      position: relative;
      width: 100%;
      height: 380px;
    }

    .stack-card {
      position: absolute;
      width: 100%;
      height: 220px;
      background: rgba(20, 28, 45, 0.8);
      backdrop-filter: blur(12px);
      border: 1px solid rgba(0, 240, 255, 0.25);
      border-radius: 20px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-weight: 600;
      box-shadow: 0 15px 30px rgba(0,0,0,0.4);
      transition: all 0.3s;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.45s cubic-bezier(0.4, 0, 0.2, 1);
    }

    .faq-item.active .faq-answer {
      max-height: 200px;
    }

    .faq-item.active .faq-icon {
      transform: rotate(180deg);
      color: #00F0FF;
    }

    .footer-link {
      color: #6B7B8D;
      transition: color 0.2s;
    }
    .footer-link:hover {
      color: #00F0FF;
    }

    input:focus {
      outline: none;
      border-color: #00F0FF;
      box-shadow: 0 0 10px rgba(0,240,255,0.4);
    }