/* roulang page: index */
:root {
      --deep-space: #0B0E2A;
      --star-cyan: #00E5FF;
      --competition-orange: #FF6B35;
      --jade-green: #00C9A7;
      --glass-bg: rgba(26, 29, 58, 0.65);
      --glass-border: rgba(0, 229, 255, 0.18);
      --text-primary: #F0F2F8;
      --text-secondary: #8A8FA8;
      --card-shadow: 0 8px 32px rgba(0, 0, 0, 0.4), inset 0 0 0 1px rgba(0, 229, 255, 0.08);
      --glow-orange: 0 0 20px rgba(255, 107, 53, 0.5);
      --glow-cyan: 0 0 12px rgba(0, 229, 255, 0.3);
      --radius-card: 16px;
      --radius-btn: 10px;
      --font-title: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
      --font-body: 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
      --font-data: 'Inter', 'SF Mono', 'PingFang SC', monospace;
    }

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

    body {
      font-family: var(--font-body);
      background-color: var(--deep-space);
      color: var(--text-primary);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      background-image: radial-gradient(circle at 20% 20%, rgba(0, 229, 255, 0.04) 0%, transparent 40%),
                        radial-gradient(circle at 80% 70%, rgba(255, 107, 53, 0.04) 0%, transparent 50%);
      background-attachment: fixed;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 导航栏 */
    .glass-nav {
      background: rgba(11, 14, 42, 0.25);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-bottom: 1px solid rgba(0, 229, 255, 0.12);
      transition: background 0.4s ease, box-shadow 0.4s ease;
      z-index: 50;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
    }
    .glass-nav.scrolled {
      background: rgba(11, 14, 42, 0.88);
      box-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
      border-bottom-color: rgba(0, 229, 255, 0.25);
    }
    .nav-link {
      color: #e0e4f0;
      font-weight: 500;
      transition: color 0.2s, text-shadow 0.2s;
      position: relative;
    }
    .nav-link:hover,
    .nav-link.active {
      color: var(--star-cyan);
      text-shadow: 0 0 8px rgba(0, 229, 255, 0.4);
    }
    .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: -6px;
      left: 50%;
      transform: translateX(-50%);
      width: 20px;
      height: 2px;
      background: var(--star-cyan);
      box-shadow: 0 0 10px var(--star-cyan);
    }

    /* 按钮 */
    .btn-primary {
      background: var(--competition-orange);
      color: white;
      font-weight: 600;
      border-radius: var(--radius-btn);
      padding: 12px 28px;
      box-shadow: var(--glow-orange);
      transition: all 0.3s ease;
      border: none;
      cursor: pointer;
      display: inline-block;
      text-align: center;
      letter-spacing: 0.3px;
    }
    .btn-primary:hover {
      box-shadow: 0 0 30px rgba(255, 107, 53, 0.8);
      transform: scale(1.03);
      background: #ff7a4d;
    }
    .btn-ghost {
      background: transparent;
      border: 1.5px solid var(--star-cyan);
      color: var(--star-cyan);
      font-weight: 600;
      border-radius: var(--radius-btn);
      padding: 12px 28px;
      transition: all 0.3s ease;
      cursor: pointer;
      display: inline-block;
      text-align: center;
    }
    .btn-ghost:hover {
      background: rgba(0, 229, 255, 0.12);
      box-shadow: 0 0 14px rgba(0, 229, 255, 0.4);
    }

    /* 玻璃卡片 */
    .glass-card {
      background: var(--glass-bg);
      backdrop-filter: blur(16px);
      -webkit-backdrop-filter: blur(16px);
      border: 1px solid var(--glass-border);
      border-radius: var(--radius-card);
      box-shadow: var(--card-shadow);
      transition: transform 0.3s ease, border-color 0.3s, box-shadow 0.3s;
    }
    .glass-card:hover {
      transform: translateY(-6px);
      border-color: rgba(0, 229, 255, 0.35);
      box-shadow: 0 12px 36px rgba(0, 0, 0, 0.5), 0 0 0 1px rgba(0, 229, 255, 0.2);
    }

    /* HERO 粒子动画 */
    @keyframes float {
      0% { transform: translateY(0px) scale(1); opacity: 0.7; }
      50% { transform: translateY(-20px) scale(1.05); opacity: 1; }
      100% { transform: translateY(0px) scale(1); opacity: 0.7; }
    }
    .particle {
      animation: float 6s infinite ease-in-out;
    }

    /* FAQ 手风琴 */
    .faq-item {
      border-bottom: 1px solid rgba(0, 229, 255, 0.15);
    }
    .faq-question {
      cursor: pointer;
      transition: color 0.2s;
    }
    .faq-question:hover {
      color: var(--star-cyan);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .faq-item.open .faq-answer {
      max-height: 250px;
    }

    /* 响应式 */
    @media (max-width: 1024px) {
      .container { padding: 0 20px; }
      h1 { font-size: 40px; line-height: 1.2; }
    }
    @media (max-width: 768px) {
      .container { padding: 0 16px; }
      h1 { font-size: 32px; }
      h2 { font-size: 28px; }
      .mobile-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: rgba(11, 14, 42, 0.95);
        backdrop-filter: blur(20px);
        padding: 24px;
        flex-direction: column;
        gap: 20px;
        border-bottom: 1px solid rgba(0,229,255,0.2);
      }
      .mobile-menu.open { display: flex; }
    }