/* roulang page: index */
:root {
      --track-black: #0B0C0E;
      --sprint-orange: #F04E23;
      --data-cyan: #00C2BA;
      --titanium-gray: #F5F5F7;
      --deep-charcoal: #1C1D21;
      --mist-white: #FAFAFC;
      --text-primary: #2D2E33;
      --text-secondary: #6A6C74;
      --border-light: #E0E0E0;
      --shadow-card: 0 1px 3px rgba(0,0,0,0.04), 0 4px 12px rgba(0,0,0,0.02);
      --shadow-card-hover: 0 8px 30px rgba(0,0,0,0.08);
      --shadow-orange-glow: 0 0 0 3px rgba(240,78,35,0.2);
      --radius-card: 12px;
      --radius-button: 8px;
      --radius-tag: 4px;
      --transition-smooth: 0.25s cubic-bezier(0.2, 0.0, 0, 1.0);
    }
    * {
      box-sizing: border-box;
    }
    body {
      margin: 0;
      font-family: 'PingFang SC', 'Microsoft YaHei', 'Inter', system-ui, -apple-system, sans-serif;
      background-color: var(--track-black);
      color: var(--text-primary);
      line-height: 1.7;
      font-size: 16px;
      font-weight: 400;
      -webkit-font-smoothing: antialiased;
    }
    h1, h2, h3, h4 {
      font-weight: 700;
      letter-spacing: -0.02em;
    }
    .font-mono-numbers {
      font-family: 'Inter', 'SF Pro Display', system-ui, monospace;
      font-feature-settings: "tnum";
      font-weight: 700;
    }
    .text-gradient-orange {
      background: linear-gradient(135deg, #F04E23 0%, #FF7A4D 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .bg-track {
      background-color: var(--track-black);
    }
    .bg-charcoal {
      background-color: var(--deep-charcoal);
    }
    .bg-titanium {
      background-color: var(--titanium-gray);
    }
    .text-cyan {
      color: var(--data-cyan);
    }
    .text-orange {
      color: var(--sprint-orange);
    }
    .border-cyan {
      border-color: var(--data-cyan);
    }
    .btn-primary {
      background-color: var(--sprint-orange);
      color: white;
      border-radius: var(--radius-button);
      padding: 14px 32px;
      font-weight: 600;
      font-size: 16px;
      transition: var(--transition-smooth);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border: none;
      cursor: pointer;
      box-shadow: 0 4px 12px rgba(240,78,35,0.3);
    }
    .btn-primary:hover {
      background-color: #D03A1A;
      box-shadow: var(--shadow-orange-glow), 0 6px 20px rgba(240,78,35,0.4);
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--data-cyan);
      color: var(--data-cyan);
      border-radius: var(--radius-button);
      padding: 14px 32px;
      font-weight: 600;
      font-size: 16px;
      transition: var(--transition-smooth);
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }
    .btn-outline:hover {
      background: rgba(0,194,186,0.05);
      border-color: #00E3D4;
      box-shadow: 0 0 12px rgba(0,194,186,0.15);
    }
    .card {
      background: var(--titanium-gray);
      border-radius: var(--radius-card);
      padding: 28px;
      box-shadow: var(--shadow-card);
      transition: var(--transition-smooth);
      border: 1px solid transparent;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
      border-color: var(--data-cyan);
    }
    .nav-sticky {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(12,13,15,0.92);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(255,255,255,0.05);
      transition: background 0.3s ease;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease-in-out, padding 0.3s ease;
    }
    .faq-item.active .faq-answer {
      max-height: 300px;
      padding-top: 12px;
    }
    .faq-item.active .faq-icon {
      transform: rotate(180deg);
      color: var(--data-cyan);
    }
    .pulse-dot {
      animation: pulse 2s infinite;
    }
    @keyframes pulse {
      0% { opacity: 0.4; transform: scale(0.8); }
      50% { opacity: 1; transform: scale(1.2); }
      100% { opacity: 0.4; transform: scale(0.8); }
    }
    .count-up {
      animation: countFlash 0.8s ease-out;
    }
    @keyframes countFlash {
      0% { opacity: 0; transform: translateY(4px); }
      50% { opacity: 1; color: var(--sprint-orange); }
      100% { opacity: 1; transform: translateY(0); }
    }
    /* 移动端汉堡菜单 */
    .mobile-menu {
      display: none;
      position: fixed;
      top: 64px;
      left: 0;
      width: 100%;
      background: rgba(12,13,15,0.98);
      backdrop-filter: blur(16px);
      padding: 24px;
      flex-direction: column;
      gap: 16px;
      z-index: 40;
      border-bottom: 1px solid rgba(255,255,255,0.05);
    }
    .mobile-menu.open {
      display: flex;
    }
    @media (max-width: 768px) {
      .desktop-nav-links {
        display: none;
      }
      .hamburger {
        display: block;
      }
      .hero-title {
        font-size: 36px;
      }
    }
    @media (min-width: 769px) {
      .hamburger {
        display: none;
      }
    }