/* roulang page: index */
* {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    :root {
      --primary: #FF4C29;
      --primary-hover: #E63A18;
      --secondary: #00E5FF;
      --accent: #FFD700;
      --bg-dark: #0D1117;
      --bg-card: #161B22;
      --bg-elevated: #1C2333;
      --text-primary: #F0F6FC;
      --text-secondary: #8B949E;
      --border: #30363D;
      --gradient-hero: linear-gradient(135deg, #0D1117 0%, #1A1F2B 100%);
      --gradient-card-hover: linear-gradient(180deg, rgba(255, 76, 41, 0.08) 0%, rgba(0, 229, 255, 0.02) 100%);
      --radius-xl: 24px;
      --radius-lg: 16px;
      --radius-md: 12px;
      --radius-sm: 8px;
      --shadow-card: 0 8px 24px rgba(0,0,0,0.4);
      --shadow-card-hover: 0 16px 32px rgba(0,0,0,0.6), 0 0 0 1px var(--border);
      --container-max: 1280px;
    }
    body {
      font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
      background-color: var(--bg-dark);
      color: var(--text-primary);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
      width: 100%;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s;
    }
    button {
      font-family: inherit;
      cursor: pointer;
      border: none;
      background: none;
    }
    /* 导航 */
    .navbar {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(28, 35, 51, 0.85);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .logo {
      font-weight: 800;
      font-size: 1.5rem;
      letter-spacing: -0.02em;
      display: flex;
      align-items: baseline;
      gap: 2px;
    }
    .logo .brand-white {
      color: var(--text-primary);
    }
    .logo .brand-primary {
      color: var(--primary);
    }
    .nav-links {
      display: flex;
      gap: 2rem;
      align-items: center;
      font-weight: 500;
      color: var(--text-secondary);
    }
    .nav-links a {
      color: var(--text-secondary);
      transition: color 0.2s;
    }
    .nav-links a:hover {
      color: var(--primary);
    }
    .btn-nav {
      background: var(--primary);
      color: white !important;
      padding: 10px 24px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      letter-spacing: 0.03em;
      transition: background 0.2s;
    }
    .btn-nav:hover {
      background: var(--primary-hover);
    }
    .mobile-nav {
      display: none;
    }
    /* Hero */
    .hero {
      background: var(--gradient-hero);
      position: relative;
      overflow: hidden;
      padding: 80px 0;
    }
    .hero::before {
      content: "";
      position: absolute;
      top: -20%;
      left: 50%;
      transform: translateX(-50%);
      width: 800px;
      height: 800px;
      background: radial-gradient(circle, rgba(255,76,41,0.15) 0%, transparent 70%);
      filter: blur(60px);
      pointer-events: none;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 3rem;
      position: relative;
      z-index: 2;
    }
    .hero-left {
      flex: 1;
    }
    .hero-badge {
      display: inline-block;
      background: rgba(0,229,255,0.15);
      color: var(--secondary);
      padding: 6px 16px;
      border-radius: 30px;
      font-size: 0.9rem;
      font-weight: 600;
      margin-bottom: 1.5rem;
      letter-spacing: 0.02em;
      border: 1px solid rgba(0,229,255,0.2);
    }
    h1 {
      font-weight: 800;
      font-size: clamp(2.5rem, 6vw, 4rem);
      letter-spacing: -0.03em;
      line-height: 1.15;
      margin-bottom: 1.5rem;
      color: var(--text-primary);
    }
    .hero-desc {
      color: var(--text-secondary);
      font-size: 1.15rem;
      margin-bottom: 2rem;
      max-width: 500px;
    }
    .hero-buttons {
      display: flex;
      gap: 1rem;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      font-weight: 600;
      padding: 14px 32px;
      border-radius: var(--radius-sm);
      letter-spacing: 0.04em;
      transition: background 0.2s, transform 0.1s;
      box-shadow: 0 4px 12px rgba(255,76,41,0.4);
    }
    .btn-primary:hover {
      background: var(--primary-hover);
    }
    .btn-outline {
      border: 1px solid var(--border);
      color: var(--text-primary);
      font-weight: 600;
      padding: 14px 32px;
      border-radius: var(--radius-sm);
      background: transparent;
      transition: 0.2s;
    }
    .btn-outline:hover {
      border-color: var(--primary);
      color: var(--primary);
    }
    .hero-right {
      flex: 1;
      display: flex;
      justify-content: center;
      align-items: center;
    }
    .visual-card {
      background: var(--bg-card);
      border-radius: var(--radius-xl);
      padding: 2rem;
      width: 100%;
      max-width: 420px;
      box-shadow: var(--shadow-card);
      border: 1px solid var(--border);
      position: relative;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      min-height: 320px;
      display: flex;
      flex-direction: column;
      justify-content: flex-end;
      overflow: hidden;
    }
    .visual-card::after {
      content: "";
      position: absolute;
      inset: 0;
      background: linear-gradient(0deg, rgba(13,17,23,0.9) 0%, rgba(13,17,23,0.4) 100%);
    }
    .data-badge {
      position: relative;
      z-index: 2;
      background: rgba(0,0,0,0.7);
      backdrop-filter: blur(8px);
      padding: 16px;
      border-radius: var(--radius-md);
      border-left: 4px solid var(--secondary);
      color: white;
    }
    .data-badge span {
      font-weight: 800;
      font-size: 2rem;
      color: var(--accent);
    }
    /* 通用板块 */
    section {
      padding: 100px 0;
    }
    .section-title {
      font-weight: 700;
      font-size: clamp(2rem, 4vw, 2.8rem);
      letter-spacing: -0.02em;
      margin-bottom: 1rem;
      display: flex;
      align-items: center;
      gap: 0.5rem;
    }
    .section-title::before {
      content: "";
      display: inline-block;
      width: 6px;
      height: 32px;
      background: var(--secondary);
      border-radius: 4px;
    }
    .section-sub {
      color: var(--text-secondary);
      margin-bottom: 3rem;
      font-size: 1.1rem;
    }
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 2rem;
    }
    .card {
      background: var(--bg-card);
      border-radius: var(--radius-lg);
      padding: 2rem;
      border: 1px solid var(--border);
      box-shadow: var(--shadow-card);
      transition: all 0.25s ease;
      position: relative;
    }
    .card:hover {
      transform: translateY(-8px);
      box-shadow: var(--shadow-card-hover);
      background: var(--bg-card);
      background-image: var(--gradient-card-hover);
    }
    .icon-box {
      width: 48px;
      height: 48px;
      background: rgba(255,76,41,0.12);
      border-radius: var(--radius-sm);
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 1.5rem;
      color: var(--primary);
      font-size: 1.5rem;
    }
    .card h3 {
      font-weight: 600;
      font-size: 1.3rem;
      margin-bottom: 0.75rem;
    }
    .card p {
      color: var(--text-secondary);
    }
    .tech-badge {
      margin-top: 1rem;
      display: inline-block;
      background: rgba(0,229,255,0.1);
      color: var(--secondary);
      font-weight: 700;
      font-size: 0.9rem;
      padding: 4px 12px;
      border-radius: 20px;
    }
    /* 流程 */
    .steps {
      display: flex;
      flex-wrap: wrap;
      gap: 2rem;
      justify-content: space-between;
    }
    .step-item {
      flex: 1;
      min-width: 200px;
      background: transparent;
      border-left: 4px solid var(--primary);
      padding-left: 1.5rem;
    }
    .step-num {
      font-size: 2.5rem;
      font-weight: 800;
      color: var(--secondary);
      opacity: 0.5;
      margin-bottom: 0.5rem;
    }
    /* 数据案例 */
    .stats-grid {
      background: var(--bg-card);
      border-radius: var(--radius-xl);
      padding: 3rem;
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(180px,1fr));
      gap: 2rem;
      text-align: center;
      border: 1px solid var(--border);
    }
    .stat-number {
      font-weight: 800;
      font-size: 2.5rem;
      color: var(--primary);
    }
    /* FAQ */
    .faq-item {
      background: var(--bg-card);
      border-radius: var(--radius-md);
      margin-bottom: 1rem;
      border: 1px solid var(--border);
      overflow: hidden;
    }
    .faq-question {
      padding: 1.25rem 1.5rem;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      background: none;
      width: 100%;
      color: var(--text-primary);
      font-size: 1.1rem;
    }
    .faq-answer {
      padding: 0 1.5rem 1.25rem;
      color: var(--text-secondary);
      display: none;
    }
    .faq-item.active .faq-answer {
      display: block;
    }
    .faq-item.active {
      background: var(--bg-elevated);
      border-left: 4px solid var(--secondary);
    }
    /* CTA */
    .cta-block {
      background: linear-gradient(135deg, var(--primary), #00c8ff);
      border-radius: var(--radius-xl);
      padding: 80px 40px;
      text-align: center;
      color: white;
    }
    .btn-white-ghost {
      border: 2px solid white;
      color: white;
      font-weight: 700;
      padding: 14px 40px;
      border-radius: 40px;
      font-size: 1.1rem;
      transition: 0.2s;
      display: inline-block;
      margin-top: 1.5rem;
    }
    .btn-white-ghost:hover {
      background: white;
      color: var(--primary);
    }
    /* 页脚 */
    .footer {
      background: var(--bg-dark);
      border-top: 1px solid var(--border);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(160px,1fr));
      gap: 2rem;
      margin-bottom: 2rem;
    }
    .footer-col h4 {
      margin-bottom: 1rem;
      font-weight: 600;
    }
    .footer-col a {
      display: block;
      color: var(--text-secondary);
      margin-bottom: 0.5rem;
      font-size: 0.95rem;
    }
    .footer-col a:hover {
      color: var(--primary);
    }
    .copyright {
      color: var(--text-secondary);
      font-size: 0.9rem;
      text-align: center;
      border-top: 1px solid var(--border);
      padding-top: 2rem;
    }
    /* 响应式 */
    @media (max-width: 992px) {
      .hero-grid {
        flex-direction: column;
        text-align: center;
      }
      .hero-left {
        display: flex;
        flex-direction: column;
        align-items: center;
      }
    }
    @media (max-width: 768px) {
      .nav-links {
        display: none;
      }
      .mobile-nav {
        display: flex;
        position: fixed;
        bottom: 16px;
        left: 16px;
        right: 16px;
        background: var(--bg-elevated);
        backdrop-filter: blur(20px);
        border-radius: 40px;
        padding: 8px 20px;
        justify-content: space-around;
        box-shadow: 0 8px 24px rgba(0,0,0,0.8);
        z-index: 60;
      }
      .mobile-nav a {
        color: var(--text-secondary);
        font-size: 0.8rem;
        display: flex;
        flex-direction: column;
        align-items: center;
        gap: 4px;
      }
      .mobile-nav .mobile-download {
        background: var(--primary);
        width: 48px;
        height: 48px;
        border-radius: 50%;
        display: flex;
        align-items: center;
        justify-content: center;
        margin-top: -20px;
        color: white;
      }
      section {
        padding: 70px 0;
      }
    }