/* roulang page: index */
:root {
      --bg-dark: #0B111E;
      --bg-sub: #10192D;
      --bg-card: rgba(22, 34, 56, 0.7);
      --tennis-volt: #CCFF00;
      --tennis-volt-glow: rgba(204, 255, 0, 0.45);
      --tech-cyan: #00F0FF;
      --text-main: #F8FAFC;
      --text-muted: #94A3B8;
      --border-line: rgba(255, 255, 255, 0.08);
    }
    
    html {
      scroll-behavior: smooth;
      background-color: var(--bg-dark);
      color: var(--text-main);
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    }

    /* 网球场域发球线微纹理背景 */
    .tennis-court-lines {
      background-image: 
        linear-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
      background-size: 60px 60px;
    }

    /* 玻璃拟态卡片 */
    .glass-panel {
      background: var(--bg-card);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border: 1px solid var(--border-line);
      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .glass-panel:hover {
      border-color: rgba(204, 255, 0, 0.35);
      transform: translateY(-2px);
      box-shadow: 0 12px 30px -10px rgba(0, 0, 0, 0.5), 0 0 15px rgba(204, 255, 0, 0.1);
    }

    /* 发光按钮 */
    .glow-btn-primary {
      background-color: var(--tennis-volt);
      color: #0B111E;
      font-weight: 700;
      transition: all 0.3s ease;
      box-shadow: 0 0 15px rgba(204, 255, 0, 0.25);
    }
    .glow-btn-primary:hover {
      background-color: #d9ff33;
      transform: translateY(-2px);
      box-shadow: 0 0 25px var(--tennis-volt-glow);
    }

    .glow-btn-outline {
      border: 1px solid rgba(204, 255, 0, 0.5);
      color: #CCFF00;
      transition: all 0.3s ease;
    }
    .glow-btn-outline:hover {
      background-color: rgba(204, 255, 0, 0.1);
      border-color: #CCFF00;
      box-shadow: 0 0 15px rgba(204, 255, 0, 0.2);
    }

    /* 手风琴状态 */
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease-out, opacity 0.3s ease;
      opacity: 0;
    }
    .faq-item.active .faq-answer {
      max-height: 240px;
      opacity: 1;
    }
    .faq-item.active .faq-icon {
      transform: rotate(180deg);
    }