/* roulang page: index */
:root {
      --bg-deep: #0A0E17;
      --bg-card: rgba(255, 255, 255, 0.03);
      --glass-bg: rgba(10, 14, 23, 0.85);
      --cyan: #00F0FF;
      --cyan-glow: rgba(0, 240, 255, 0.4);
      --purple: #B300FF;
      --text-primary: #EAECF0;
      --text-secondary: #9BA1B0;
      --text-muted: #6B7280;
      --border-subtle: rgba(0, 240, 255, 0.15);
      --border-hover: rgba(0, 240, 255, 0.5);
      --radius-lg: 16px;
      --radius-md: 12px;
      --radius-sm: 8px;
      --shadow-cyan: 0 0 24px rgba(0, 240, 255, 0.5);
      --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --transition-smooth: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      background-color: var(--bg-deep);
      color: var(--text-primary);
      font-family: var(--font-sans);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    img {
      max-width: 100%;
      display: block;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
    }
    /* 导航 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: var(--glass-bg);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-bottom: 1px solid rgba(0, 240, 255, 0.2);
      z-index: 100;
      transition: var(--transition-smooth);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .logo {
      font-size: 24px;
      font-weight: 800;
      color: var(--cyan);
      letter-spacing: -0.3px;
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .logo span {
      width: 3px;
      height: 20px;
      background: var(--purple);
      border-radius: 2px;
    }
    .nav-menu {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .nav-link {
      color: var(--text-secondary);
      font-weight: 500;
      font-size: 15px;
      position: relative;
      padding: 8px 0;
      transition: color 0.2s;
    }
    .nav-link:hover, .nav-link:focus-visible {
      color: var(--cyan);
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--cyan);
      box-shadow: 0 0 10px var(--cyan);
      transition: width 0.25s ease;
    }
    .nav-link:hover::after, .nav-link:focus-visible::after {
      width: 100%;
    }
    .btn-outline-sm {
      border: 1px solid var(--cyan);
      color: var(--cyan);
      padding: 10px 22px;
      border-radius: 30px;
      font-weight: 600;
      font-size: 14px;
      transition: var(--transition-smooth);
      background: transparent;
    }
    .btn-outline-sm:hover {
      background: rgba(0, 240, 255, 0.08);
      box-shadow: 0 0 18px rgba(0, 240, 255, 0.35);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 6px;
      background: transparent;
      border: none;
      cursor: pointer;
    }
    .hamburger span {
      width: 26px;
      height: 2px;
      background: var(--cyan);
      transition: var(--transition-smooth);
    }
    @media (max-width: 768px) {
      .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        width: 100%;
        background: rgba(10, 14, 23, 0.96);
        backdrop-filter: blur(24px);
        flex-direction: column;
        gap: 28px;
        padding: 40px 24px;
        align-items: center;
        transform: translateX(100%);
        transition: transform 0.35s ease;
        z-index: 99;
      }
      .nav-menu.open {
        transform: translateX(0);
      }
      .hamburger {
        display: flex;
      }
    }
    /* 通用板块 */
    section {
      padding: 80px 0;
    }
    .section-title {
      font-size: 36px;
      font-weight: 700;
      color: var(--text-primary);
      margin-bottom: 12px;
      line-height: 1.2;
    }
    .section-subtitle {
      font-size: 16px;
      color: var(--text-secondary);
      margin-bottom: 48px;
    }
    .btn-primary {
      background: var(--cyan);
      color: #0A0E17;
      font-weight: 700;
      font-size: 16px;
      padding: 14px 32px;
      border-radius: 8px;
      transition: var(--transition-smooth);
      display: inline-flex;
      align-items: center;
      gap: 8px;
      box-shadow: 0 4px 20px rgba(0, 240, 255, 0.25);
    }
    .btn-primary:hover {
      background: #33F5FF;
      box-shadow: 0 0 28px rgba(0, 240, 255, 0.6);
      transform: scale(1.03);
    }
    .btn-ghost {
      border: 1px solid var(--cyan);
      color: var(--cyan);
      padding: 14px 32px;
      border-radius: 8px;
      font-weight: 600;
      transition: var(--transition-smooth);
    }
    .btn-ghost:hover {
      background: rgba(0,240,255,0.08);
    }
    /* Hero */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: radial-gradient(circle at 20% 20%, rgba(0,240,255,0.08), transparent 50%), 
                  radial-gradient(circle at 80% 60%, rgba(179,0,255,0.08), transparent 60%);
      position: relative;
      overflow: hidden;
    }
    .hero-grid {
      display: flex;
      flex-wrap: wrap;
      align-items: center;
      gap: 40px;
    }
    .hero-content {
      flex: 1 1 500px;
    }
    .hero h1 {
      font-size: 48px;
      font-weight: 800;
      line-height: 1.15;
      color: #FFFFFF;
      letter-spacing: -0.5px;
      margin-bottom: 20px;
    }
    .hero-sub {
      font-size: 18px;
      color: #B0B8C5;
      margin-bottom: 32px;
      max-width: 560px;
    }
    .hero-image {
      flex: 1 1 400px;
      border-radius: 24px;
      overflow: hidden;
      border: 1px solid var(--border-subtle);
      backdrop-filter: blur(8px);
      box-shadow: 0 20px 40px rgba(0,0,0,0.5);
    }
    .hero-image img {
      width: 100%;
      height: auto;
      object-fit: cover;
    }
    .scroll-hint {
      position: absolute;
      bottom: 25px;
      left: 50%;
      transform: translateX(-50%);
      animation: bounce 2s infinite;
      font-size: 24px;
      color: var(--cyan);
    }
    @keyframes bounce {
      0%,100%{transform:translateX(-50%)translateY(0);}
      50%{transform:translateX(-50%)translateY(8px);}
    }
    /* 卡片 */
    .card-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
      gap: 30px;
    }
    .card {
      background: var(--glass-bg);
      backdrop-filter: blur(12px);
      border: 1px solid var(--border-subtle);
      border-radius: var(--radius-lg);
      padding: 28px 24px;
      transition: var(--transition-smooth);
    }
    .card:hover {
      border-color: var(--border-hover);
      box-shadow: 0 8px 32px rgba(0,240,255,0.12);
      transform: translateY(-4px);
    }
    .card-icon {
      width: 54px;
      height: 54px;
      background: rgba(0,240,255,0.1);
      border-radius: 14px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      font-size: 26px;
      color: var(--cyan);
    }
    .card h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 10px;
    }
    .stat-number {
      font-size: 56px;
      font-weight: 800;
      background: linear-gradient(135deg, #00F0FF, #B300FF);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }
    /* FAQ */
    .faq-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 24px;
    }
    .faq-item {
      background: rgba(0,240,255,0.02);
      border: 1px solid var(--border-subtle);
      border-radius: 12px;
    }
    .faq-question {
      width: 100%;
      background: transparent;
      padding: 20px;
      font-weight: 600;
      font-size: 16px;
      text-align: left;
      color: var(--text-primary);
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      padding: 0 20px 18px;
      color: var(--text-secondary);
      display: none;
    }
    .faq-item.open .faq-answer {
      display: block;
    }
    @media (max-width: 768px) {
      .faq-grid { grid-template-columns: 1fr; }
      .hero h1 { font-size: 32px; }
      .section-title { font-size: 28px; }
    }
    footer {
      background: #0D1320;
      padding: 60px 0 30px;
      border-top: 1px solid rgba(0,240,255,0.1);
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1.2fr 1fr;
      gap: 40px;
    }
    @media (max-width: 768px) {
      .footer-grid { grid-template-columns: 1fr; }
    }