/* roulang page: index */
:root {
      --primary: #0B4F4F;
      --primary-dark: #083a3a;
      --accent: #00C9A7;
      --accent-glow: rgba(0, 201, 167, 0.4);
      --bg-dark: #0D1117;
      --bg-darker: #111C1F;
      --bg-light: #F4F6F9;
      --card-bg: #FFFFFF;
      --text-heading: #1A1A1A;
      --text-body: #4A4A4A;
      --text-on-dark: #E8EDF2;
      --text-muted: #8899AA;
      --border-light: #E5E9F0;
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-icon: 8px;
      --radius-input: 6px;
      --shadow-card: 0 2px 8px rgba(0,0,0,0.06);
      --shadow-hover: 0 8px 24px rgba(0,0,0,0.12);
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', system-ui, -apple-system, 'Segoe UI', sans-serif;
      --font-mono: 'Inter', 'SF Mono', 'Cascadia Code', monospace;
      --transition: 0.2s ease;
      --nav-height: 72px;
    }
    * { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; }
    body {
      font-family: var(--font-sans);
      background: var(--bg-light);
      color: var(--text-body);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
    }
    img { max-width: 100%; height: auto; display: block; }
    a { text-decoration: none; color: inherit; transition: color var(--transition); }
    ul { list-style: none; }

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

    /* 导航 */
    .nav {
      position: fixed;
      top: 0; left: 0; width: 100%;
      height: var(--nav-height);
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 0 32px;
      z-index: 1000;
      transition: background 0.3s, backdrop-filter 0.3s, box-shadow 0.3s;
    }
    .nav.scrolled {
      background: rgba(13, 17, 23, 0.94);
      backdrop-filter: blur(12px);
      box-shadow: 0 4px 16px rgba(0,0,0,0.25);
    }
    .logo {
      font-size: 1.65rem;
      font-weight: 700;
      color: #fff;
      display: flex;
      align-items: baseline;
      gap: 2px;
      letter-spacing: -0.3px;
    }
    .logo .accent-dot {
      color: var(--accent);
      font-size: 1.8rem;
      margin-right: 4px;
    }
    .logo small {
      font-size: 0.85rem;
      font-weight: 500;
      color: #CCD6E0;
      margin-left: 2px;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
      font-size: 0.95rem;
      font-weight: 500;
      color: #CCD6E0;
    }
    .nav-links a {
      position: relative;
      padding: 4px 0;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      left: 0; bottom: -2px;
      width: 0;
      height: 2px;
      background: var(--accent);
      transition: width 0.25s ease;
    }
    .nav-links a:hover { color: var(--accent); }
    .nav-links a:hover::after { width: 100%; }
    .nav-cta {
      background: linear-gradient(135deg, var(--primary), var(--accent));
      color: #fff;
      padding: 10px 26px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 0.95rem;
      transition: filter 0.2s, box-shadow 0.2s, transform 0.15s;
      box-shadow: 0 4px 12px rgba(0,201,167,0.25);
      white-space: nowrap;
    }
    .nav-cta:hover {
      filter: brightness(1.15);
      box-shadow: 0 0 16px var(--accent-glow);
      transform: scale(1.02);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
      padding: 4px;
    }
    .hamburger span {
      width: 26px;
      height: 2px;
      background: #fff;
      transition: 0.3s;
      border-radius: 2px;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      inset: 0;
      background: rgba(13,17,23,0.96);
      backdrop-filter: blur(16px);
      flex-direction: column;
      justify-content: center;
      align-items: center;
      gap: 36px;
      z-index: 999;
    }
    .mobile-menu a {
      font-size: 1.5rem;
      color: #E8EDF2;
      font-weight: 500;
    }
    .mobile-menu .nav-cta {
      margin-top: 20px;
      font-size: 1.1rem;
      padding: 14px 32px;
    }

    /* Hero */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: radial-gradient(circle at 20% 30%, #0B4F4F, #0D1117 75%);
      position: relative;
      overflow: hidden;
      padding-top: var(--nav-height);
    }
    .hero-content {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      gap: 40px;
    }
    .hero-text {
      flex: 0 0 52%;
      color: #E8EDF2;
      z-index: 2;
    }
    .hero h1 {
      font-size: 3.6rem;
      font-weight: 700;
      line-height: 1.2;
      letter-spacing: -0.5px;
      margin-bottom: 20px;
      color: #fff;
    }
    .hero h1 span {
      color: var(--accent);
    }
    .hero-sub {
      font-size: 1.35rem;
      font-weight: 500;
      color: #CCD6E0;
      margin-bottom: 24px;
    }
    .hero-desc {
      font-size: 1.1rem;
      color: #B0BEC5;
      max-width: 480px;
      margin-bottom: 36px;
      line-height: 1.7;
    }
    .hero-actions {
      display: flex;
      gap: 18px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: linear-gradient(135deg, var(--primary), var(--accent));
      color: #fff;
      font-weight: 600;
      padding: 14px 34px;
      border-radius: var(--radius-btn);
      transition: filter 0.2s, box-shadow 0.2s, transform 0.15s;
      box-shadow: 0 6px 18px rgba(0,201,167,0.3);
      display: inline-block;
      text-align: center;
    }
    .btn-primary:hover {
      filter: brightness(1.15);
      box-shadow: 0 0 20px var(--accent-glow);
      transform: translateY(-1px);
    }
    .btn-outline {
      border: 2px solid var(--accent);
      color: var(--accent);
      background: transparent;
      font-weight: 600;
      padding: 13px 32px;
      border-radius: var(--radius-btn);
      transition: background 0.2s, color 0.2s;
    }
    .btn-outline:hover {
      background: rgba(0,201,167,0.12);
      color: #fff;
    }
    .hero-visual {
      flex: 0 0 42%;
      position: relative;
      height: 420px;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .signal-ring {
      width: 320px;
      height: 320px;
      border-radius: 50%;
      background: radial-gradient(circle, rgba(0,201,167,0.25) 0%, transparent 70%);
      position: absolute;
      animation: pulseRing 2.8s infinite;
    }
    .signal-wave {
      position: absolute;
      width: 100%;
      height: 100%;
      background: repeating-linear-gradient(0deg, transparent, transparent 4px, rgba(0,201,167,0.2) 5px);
      mask: radial-gradient(circle, black 35%, transparent 70%);
    }
    @keyframes pulseRing {
      0% { transform: scale(0.9); opacity: 0.7; }
      50% { transform: scale(1.15); opacity: 0.35; }
      100% { transform: scale(0.9); opacity: 0.7; }
    }
    .particle {
      position: absolute;
      width: 4px; height: 4px;
      background: var(--accent);
      border-radius: 50%;
      opacity: 0.6;
      animation: float 6s infinite alternate;
    }
    @keyframes float {
      0% { transform: translateY(0px); }
      100% { transform: translateY(-30px); }
    }

    /* 通用板块 */
    section {
      padding: 90px 0;
    }
    .section-title {
      font-size: 2.4rem;
      font-weight: 700;
      color: var(--text-heading);
      margin-bottom: 18px;
      letter-spacing: -0.3px;
    }
    .section-sub {
      color: #5A6A7A;
      max-width: 600px;
      margin-bottom: 48px;
    }

    /* 核心优势 非对称网格 */
    .advantages-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 28px;
    }
    .adv-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 32px 28px;
      box-shadow: var(--shadow-card);
      display: flex;
      gap: 20px;
      align-items: flex-start;
      transition: box-shadow 0.25s, transform 0.2s;
    }
    .adv-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-3px);
    }
    .adv-icon {
      background: rgba(0,201,167,0.12);
      width: 52px; height: 52px;
      display: flex;
      align-items: center;
      justify-content: center;
      border-radius: var(--radius-icon);
      color: var(--primary);
      font-size: 1.5rem;
      flex-shrink: 0;
    }
    .adv-card.wide {
      grid-column: span 2;
    }
    @media (max-width: 768px) {
      .advantages-grid {
        grid-template-columns: 1fr;
      }
      .adv-card.wide {
        grid-column: span 1;
      }
    }

    /* 服务矩阵 水平滚动卡片 */
    .service-scroll {
      display: flex;
      gap: 24px;
      overflow-x: auto;
      padding-bottom: 18px;
      scroll-snap-type: x mandatory;
      -webkit-overflow-scrolling: touch;
    }
    .service-card {
      flex: 0 0 300px;
      background: var(--card-bg);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      scroll-snap-align: start;
      transition: transform 0.25s, box-shadow 0.25s;
      overflow: hidden;
    }
    .service-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }
    .service-img {
      background: #c8e6e0;
      height: 170px;
      background-size: cover;
      background-position: center;
      position: relative;
    }
    .service-info {
      padding: 20px 22px;
    }
    .service-info h3 {
      font-size: 1.25rem;
      font-weight: 600;
      margin-bottom: 8px;
    }

    /* 数据实力 */
    .stats-row {
      display: flex;
      justify-content: space-between;
      flex-wrap: wrap;
      gap: 30px;
      text-align: center;
      background: #fff;
      border-radius: var(--radius-card);
      padding: 48px 32px;
      box-shadow: var(--shadow-card);
    }
    .stat-number {
      font-size: 2.8rem;
      font-weight: 700;
      color: var(--primary);
      font-family: var(--font-mono);
    }
    .stat-label {
      font-weight: 600;
      margin-top: 6px;
      color: var(--text-heading);
    }
    .stat-desc {
      color: #6b7b8b;
      font-size: 0.9rem;
      margin-top: 4px;
    }

    /* 案例 */
    .logo-wall {
      display: flex;
      flex-wrap: wrap;
      gap: 28px;
      justify-content: center;
      filter: grayscale(1);
      opacity: 0.7;
      margin-bottom: 48px;
    }
    .logo-wall img {
      height: 38px;
      transition: filter 0.3s, opacity 0.3s;
    }
    .logo-wall img:hover {
      filter: grayscale(0);
      opacity: 1;
    }
    .case-cards {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 28px;
    }

    /* FAQ */
    .faq-item {
      background: #fff;
      border-bottom: 1px solid var(--border-light);
      border-radius: 0;
    }
    .faq-question {
      width: 100%;
      background: transparent;
      border: none;
      padding: 18px 22px;
      text-align: left;
      font-weight: 600;
      font-size: 1.05rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--text-heading);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.2s;
      background: #F8FAFB;
      padding: 0 22px;
      color: #4A4A4A;
    }
    .faq-item.active .faq-answer {
      max-height: 220px;
      padding: 16px 22px;
    }

    /* CTA 区域 */
    .cta-block {
      background: linear-gradient(135deg, #0B4F4F, #0A3A3A);
      color: #fff;
      text-align: center;
      padding: 80px 20px;
      border-radius: 0;
    }
    .cta-block h2 {
      font-size: 2.5rem;
      font-weight: 700;
      margin-bottom: 16px;
    }
    .footer {
      background: #0B1215;
      color: #8899AA;
      padding: 62px 0 28px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 1.5fr 1fr 1fr 1fr;
      gap: 36px;
    }
    .footer a:hover { color: var(--accent); }

    @media (max-width: 1024px) {
      .hero h1 { font-size: 2.8rem; }
      .hero-content { flex-direction: column; text-align: center; }
      .hero-visual { height: 280px; }
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .case-cards { grid-template-columns: 1fr; }
    }
    @media (max-width: 640px) {
      .container { padding: 0 18px; }
      .hero h1 { font-size: 2.2rem; }
      .stats-row { flex-direction: column; align-items: center; }
      .footer-grid { grid-template-columns: 1fr; }
    }