:root {
      --primary: #0088FF;
      --primary-dark: #0066CC;
      --primary-light: #E6F4FF;
      --accent: #00C4FF;
      --success: #28C76F;
      --text-dark: #1A1A2E;
      --text-gray: #5A5A6E;
      --bg-light: #F7F9FC;
      --bg-section: #F0F5FA;
      --border: #E2E8F0;
    }

    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
      color: var(--text-dark);
      line-height: 1.65;
      font-size: 16px;
      background: #fff;
    }

    p, li, .lead-text {
      font-size: 16px;
    }

    h1, h2, h3, h4, h5 {
      font-weight: 700;
      color: var(--text-dark);
    }

    a { text-decoration: none; }

    /* Buttons */
    .btn-primary-custom {
      background: linear-gradient(135deg, #0088FF 0%, #00C4FF 100%);
      border: none;
      color: #fff;
      font-weight: 600;
      padding: 14px 32px;
      border-radius: 8px;
      font-size: 16px;
      box-shadow: 0 4px 14px rgba(0, 136, 255, 0.35);
      transition: all 0.25s ease;
    }
    .btn-primary-custom:hover {
      transform: translateY(-2px);
      box-shadow: 0 6px 20px rgba(0, 136, 255, 0.45);
      color: #fff;
    }
    .btn-outline-custom {
      background: transparent;
      border: 2px solid #0088FF;
      color: #0088FF;
      font-weight: 600;
      padding: 12px 30px;
      border-radius: 8px;
      font-size: 16px;
      transition: all 0.25s ease;
    }
    .btn-outline-custom:hover {
      background: #E6F4FF;
      color: #0066CC;
    }

    /* Hero */
    .hero {
      background: linear-gradient(180deg, #E6F4FF 0%, #FFFFFF 85%);
      padding: 70px 0 50px;
      overflow: hidden;
    }
    .hero-badge {
      display: inline-block;
      background: #E6F4FF;
      color: #0088FF;
      font-size: 13px;
      font-weight: 600;
      padding: 6px 14px;
      border-radius: 50px;
      margin-bottom: 18px;
    }
    .hero h1 {
      font-size: 2.4rem;
      line-height: 1.25;
      margin-bottom: 18px;
    }
    .hero h1 .highlight { color: #0088FF; }
    .hero-desc {
      font-size: 16px;
      color: var(--text-gray);
      max-width: 520px;
      margin-bottom: 28px;
    }

    /* Dynamic Transfer Visual */
    .transfer-visual {
      background: #fff;
      border-radius: 16px;
      box-shadow: 0 20px 50px rgba(0, 136, 255, 0.12);
      border: 1px solid var(--border);
      padding: 28px 20px;
      position: relative;
      min-height: 340px;
    }
    .transfer-stage {
      position: relative;
      height: 280px;
      display: flex;
      align-items: center;
      justify-content: space-between;
    }
    .platform-node {
      width: 90px;
      text-align: center;
      z-index: 2;
    }
    .platform-node .icon-box {
      width: 64px;
      height: 64px;
      background: var(--primary-light);
      border-radius: 14px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 8px;
      font-size: 28px;
      box-shadow: 0 4px 12px rgba(0, 136, 255, 0.15);
    }
    .platform-node span {
      font-size: 12px;
      font-weight: 600;
      color: var(--text-dark);
    }

    /* Moving playlist cards */
    .playlist-card {
      position: absolute;
      background: linear-gradient(135deg, #0088FF, #00C4FF);
      color: #fff;
      padding: 8px 14px;
      border-radius: 8px;
      font-size: 12px;
      font-weight: 600;
      white-space: nowrap;
      box-shadow: 0 4px 12px rgba(0, 136, 255, 0.4);
      z-index: 3;
      opacity: 0;
    }
    .playlist-card.p1 { animation: fly1 3.2s ease-in-out infinite; }
    .playlist-card.p2 { animation: fly2 3.2s ease-in-out infinite 0.7s; }
    .playlist-card.p3 { animation: fly3 3.2s ease-in-out infinite 1.4s; }

    @keyframes fly1 {
      0%   { left: 12%; top: 30%; opacity: 0; transform: scale(0.7); }
      15%  { opacity: 1; transform: scale(1); }
      50%  { left: 42%; top: 45%; opacity: 1; }
      85%  { opacity: 1; transform: scale(1); }
      100% { left: 72%; top: 28%; opacity: 0; transform: scale(0.7); }
    }
    @keyframes fly2 {
      0%   { left: 12%; top: 55%; opacity: 0; transform: scale(0.7); }
      15%  { opacity: 1; transform: scale(1); }
      50%  { left: 42%; top: 40%; opacity: 1; }
      85%  { opacity: 1; transform: scale(1); }
      100% { left: 72%; top: 58%; opacity: 0; transform: scale(0.7); }
    }
    @keyframes fly3 {
      0%   { left: 12%; top: 42%; opacity: 0; transform: scale(0.7); }
      15%  { opacity: 1; transform: scale(1); }
      50%  { left: 42%; top: 55%; opacity: 1; }
      85%  { opacity: 1; transform: scale(1); }
      100% { left: 72%; top: 42%; opacity: 0; transform: scale(0.7); }
    }

    /* Pulsing center arrow */
    .center-flow {
      position: absolute;
      left: 50%;
      top: 50%;
      transform: translate(-50%, -50%);
      z-index: 1;
      width: 120px;
      text-align: center;
    }
    .center-flow .pulse-arrow {
      font-size: 32px;
      color: #0088FF;
      animation: pulse 1.5s ease-in-out infinite;
    }
    @keyframes pulse {
      0%, 100% { opacity: 0.5; transform: scale(0.9); }
      50% { opacity: 1; transform: scale(1.15); }
    }
    .speed-tag {
      display: inline-block;
      background: #28C76F;
      color: #fff;
      font-size: 11px;
      font-weight: 700;
      padding: 3px 10px;
      border-radius: 20px;
      margin-top: 6px;
    }

    /* Stats bar */
    .stats-bar {
      background: #fff;
      border-top: 1px solid var(--border);
      border-bottom: 1px solid var(--border);
      padding: 36px 0;
    }
    .stat-item { text-align: center; }
    .stat-number {
      font-size: 2rem;
      font-weight: 800;
      color: #0088FF;
      line-height: 1.2;
    }
    .stat-label {
      font-size: 14px;
      color: var(--text-gray);
      margin-top: 4px;
    }

    /* Section common */
    .section { padding: 70px 0; }
    .section-alt { background: var(--bg-section); }
    .section-label {
      display: inline-block;
      font-size: 13px;
      font-weight: 600;
      color: #0088FF;
      text-transform: uppercase;
      letter-spacing: 1px;
      margin-bottom: 10px;
    }
    .section-title {
      font-size: 1.85rem;
      margin-bottom: 12px;
    }
    .section-desc {
      font-size: 16px;
      color: var(--text-gray);
      max-width: 640px;
      margin: 0 auto 40px;
    }

    /* Cards */
    .feature-card, .pain-card, .why-card {
      background: #fff;
      border: 1px solid var(--border);
      border-radius: 12px;
      padding: 28px 24px;
      height: 100%;
      transition: all 0.25s;
    }
    .feature-card:hover, .pain-card:hover {
      border-color: #0088FF;
      box-shadow: 0 8px 24px rgba(0, 136, 255, 0.1);
    }
    .icon-circle {
      width: 48px;
      height: 48px;
      background: var(--primary-light);
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 22px;
      color: #0088FF;
      margin-bottom: 16px;
    }
    .feature-card h5, .pain-card h5, .why-card h5 {
      font-size: 17px;
      margin-bottom: 10px;
    }

    /* Version cards */
    .version-card {
      background: #fff;
      border: 2px solid var(--border);
      border-radius: 14px;
      padding: 36px 30px;
      height: 100%;
      position: relative;
    }
    .version-card.popular {
      border-color: #0088FF;
      box-shadow: 0 12px 36px rgba(0, 136, 255, 0.15);
    }
    .version-card.popular .badge-rec {
      position: absolute;
      top: -12px;
      left: 50%;
      transform: translateX(-50%);
      background: linear-gradient(135deg, #0088FF, #00C4FF);
      color: #fff;
      font-size: 11px;
      font-weight: 700;
      padding: 4px 14px;
      border-radius: 50px;
      letter-spacing: 0.5px;
    }
    .version-card ul {
      list-style: none;
      padding: 0;
      margin: 20px 0 28px;
    }
    .version-card li {
      padding: 7px 0;
      font-size: 15px;
      display: flex;
      align-items: flex-start;
    }
    .version-card li .check { color: #28C76F; font-weight: 700; margin-right: 10px; }
    .version-card li .cross { color: #ccc; margin-right: 10px; }

    /* Comparison table */
    .table thead th {
      background: #0088FF;
      color: #fff;
      border: none;
      font-weight: 600;
      font-size: 15px;
    }
    .table td, .table th {
      vertical-align: middle;
      font-size: 15px;
      padding: 14px 18px;
    }
    .table-striped tbody tr:nth-of-type(odd) { background-color: #F7F9FC; }
    .check-cell { color: #28C76F; font-weight: 700; font-size: 18px; }
    .cross-cell { color: #ccc; font-size: 18px; }

    /* Steps */
    .step-number {
      width: 52px;
      height: 52px;
      background: linear-gradient(135deg, #0088FF, #00C4FF);
      color: #fff;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 20px;
      font-weight: 700;
      margin: 0 auto 16px;
      box-shadow: 0 6px 16px rgba(0, 136, 255, 0.3);
    }

    /* Platforms */
    .platform-tag {
      display: inline-block;
      background: #fff;
      border: 1px solid var(--border);
      border-radius: 8px;
      padding: 12px 22px;
      font-size: 15px;
      font-weight: 600;
      margin: 6px;
      box-shadow: 0 2px 8px rgba(0,0,0,0.04);
    }

    /* Testimonials */
    .testimonial-card {
      background: #fff;
      border: 1px solid var(--border);
      border-radius: 12px;
      padding: 28px 24px;
      height: 100%;
    }
    .stars { color: #FFB800; font-size: 16px; margin-bottom: 12px; }
    .testimonial-text {
      font-size: 15px;
      color: var(--text-gray);
      font-style: italic;
      margin-bottom: 18px;
    }
    .testimonial-author {
      font-weight: 600;
      font-size: 15px;
    }
    .testimonial-meta {
      font-size: 13px;
      color: #8A8A9E;
    }

    /* CTA */
    .cta-banner {
      background: linear-gradient(135deg, #0066CC 0%, #0088FF 50%, #00C4FF 100%);
      padding: 64px 0;
      text-align: center;
      color: #fff;
    }
    .cta-banner h2 { color: #fff; font-size: 1.85rem; margin-bottom: 12px; }
    .cta-banner p { font-size: 16px; opacity: 0.92; max-width: 560px; margin: 0 auto 28px; }
    .cta-banner .btn-primary-custom {
      background: #fff;
      color: #0088FF;
      box-shadow: 0 4px 20px rgba(0,0,0,0.15);
    }
    .cta-banner .btn-primary-custom:hover {
      background: #f0f7ff;
      color: #0066CC;
    }

    /* FAQ */
    .faq-item {
      background: #fff;
      border: 1px solid var(--border);
      border-radius: 10px;
      margin-bottom: 12px;
      overflow: hidden;
    }
    .faq-question {
      padding: 18px 22px;
      font-size: 16px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      margin: 0;
    }
    .faq-answer {
      padding: 0 22px 18px;
      font-size: 16px;
      color: var(--text-gray);
      display: none;
    }
    .faq-item.active .faq-answer { display: block; }

    @media (max-width: 991.98px) {
      .hero h1 { font-size: 1.9rem; }
      .transfer-visual { margin-top: 36px; }
    }
    @media (max-width: 575.98px) {
      .hero { padding: 48px 0 36px; }
      .section { padding: 50px 0; }
      .stat-number { font-size: 1.6rem; }
    }

    /* ============================================================
       NB Transfer — Section layout fix (Versions / Comparison)
       说明：本段用于替代 Bootstrap 栅格，使区块在桌面端独立成行并居中。
       ============================================================ */

    /* 1. 通用区块容器：整行铺满 + 内容居中，不依赖 .container / .row */
    .nbt-section {
      display: block;
      width: 100%;
      padding: 70px 0;
      box-sizing: border-box;
    }
    .nbt-section.is-alt { background: var(--bg-section); }

    .nbt-wrap {
      width: 100%;
      max-width: 1110px;   /* 与站点 .w1110 保持一致 */
      margin: 0 auto;
      padding: 0 20px;
      box-sizing: border-box;
    }

    .nbt-head { text-align: center; margin-bottom: 44px; }
    .nbt-head .section-title { margin-bottom: 12px; }
    .nbt-head .section-desc { margin: 0 auto; }

    /* 兜底：万一区块仍被放在 .body-box.row 内部，强制其独占一行 */
    .body-box > .nbt-section {
      flex: 0 0 100%;
      width: calc(100% - 30px);
      margin-left: 15px;
      margin-right: 15px;
      float: none;
      clear: both;
    }

    /* 2. 版本对比卡片：flex 居中 + 等高 + 按钮底部对齐 */
    .nbt-plan-grid {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      align-items: stretch;
      margin: -15px;            /* 不用 flex gap：iOS Safari 14.0 及更早不支持 */
    }
    .nbt-plan {
      flex: 0 1 400px;
      max-width: 420px;
      min-width: 0;
      display: flex;
      padding: 15px;
      box-sizing: border-box;
    }
    .nbt-plan > .version-card {
      display: flex;
      flex-direction: column;
      width: 100%;
      height: auto;
      margin: 0;
    }
    .version-card .plan-name {
      font-size: 1.4rem;
      margin-bottom: 6px;
    }
    .version-card .plan-sub {
      font-size: 15px;
      color: var(--text-gray);
      margin-bottom: 0;
    }
    .nbt-plan > .version-card > ul { flex: 1 1 auto; }
    .version-card .plan-cta {
      display: block;
      width: 100%;
      text-align: center;
      margin-top: auto;      /* 两张卡条目数不同时，按钮仍在同一水平线 */
      white-space: nowrap;
    }
    .version-card.popular { overflow: visible; }

    /* 3. 对比表格：圆角靠外层容器实现，移动端可横向滑动 */
    .nbt-table-wrap {
      background: #fff;
      border: 1px solid var(--border);
      border-radius: 12px;
      overflow-x: auto;
      -webkit-overflow-scrolling: touch;
    }
    .nbt-table {
      width: 100%;
      min-width: 560px;
      margin: 0;
      border-collapse: collapse;
      background: #fff;
    }
    .nbt-table th,
    .nbt-table td {
      padding: 14px 18px;
      font-size: 15px;
      text-align: center;
      vertical-align: middle;
      border-bottom: 1px solid var(--border);
    }
    .nbt-table thead th {
      background: var(--primary);
      color: #fff;
      font-weight: 600;
      border-bottom: none;
    }
    .nbt-table th:first-child,
    .nbt-table td:first-child { text-align: left; }
    .nbt-table tbody tr:nth-child(odd) { background: #F7F9FC; }
    .nbt-table tbody tr:last-child td { border-bottom: none; }

    .nbt-table-hint {
      display: none;
      margin: 10px 0 0;
      font-size: 13px;
      color: var(--text-gray);
      text-align: center;
    }

    /* 4. 响应式 */
    @media (max-width: 991.98px) {
      .nbt-section { padding: 56px 0; }
      .nbt-plan { flex: 1 1 100%; max-width: 480px; }
    }

    /* 移动端表格：首列吸附，横向滑动时功能名不会跟着滑走 */
    @media (max-width: 767.98px) {
      .nbt-table th:first-child,
      .nbt-table td:first-child {
        position: sticky;
        left: 0;
        z-index: 1;
        background: #fff;
        box-shadow: 1px 0 0 var(--border);
      }
      .nbt-table thead th:first-child { background: var(--primary); z-index: 2; }
      .nbt-table tbody tr:nth-child(odd) td:first-child { background: #F7F9FC; }
      .nbt-table th, .nbt-table td { padding: 12px 14px; font-size: 14px; }
      .nbt-table-hint { display: block; }
    }
    @media (max-width: 575.98px) {
      .nbt-section { padding: 44px 0; }
      .nbt-wrap { padding: 0 15px; }     /* 与相邻站点原生模块的栅格间距一致 */
      .nbt-head { margin-bottom: 32px; }
      .nbt-plan-grid { margin: -10px; }
      .nbt-plan { padding: 10px; }
      .version-card { padding: 28px 22px; }
    }


    /* ============================================================
       NB Transfer — FAQ 手风琴（覆盖上方 .faq-* 基础样式）
       ============================================================ */

    .nbt-section[id] { scroll-margin-top: 90px; }   /* 顶部导航吸顶时的锚点偏移 */

    .nbt-faq {
      max-width: 860px;
      margin: 0 auto;
    }

    .nbt-faq .faq-item {
      background: #fff;
      border: 1px solid var(--border);
      border-radius: 10px;
      margin-bottom: 12px;
      overflow: hidden;
      transition: border-color 0.2s ease, box-shadow 0.2s ease;
    }
    .nbt-faq .faq-item:last-child { margin-bottom: 0; }
    .nbt-faq .faq-item:hover { border-color: #BFDFFF; }
    .nbt-faq .faq-item.active {
      border-color: var(--primary);
      box-shadow: 0 6px 20px rgba(0, 136, 255, 0.08);
    }

    /* h3 只承担语义层级，视觉尺寸沿用原来的 h5 观感 */
    .nbt-faq .faq-question-h {
      margin: 0;
      font-size: inherit;
      font-weight: inherit;
    }

    /* button 重置为整行可点击区域，键盘可聚焦 */
    .nbt-faq .faq-question {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 16px;
      width: 100%;
      margin: 0;
      padding: 18px 22px;
      background: none;
      border: 0;
      text-align: left;
      font-family: inherit;
      font-size: 16px;
      font-weight: 600;
      line-height: 1.5;
      color: var(--text-dark);
      cursor: pointer;
    }
    .nbt-faq .faq-question:hover { color: var(--primary); }
    .nbt-faq .faq-question:focus {
      outline: 2px solid var(--primary);
      outline-offset: -2px;
      border-radius: 10px;
    }
    .nbt-faq .faq-question:focus:not(:focus-visible) { outline: none; }

    /* +/− 图标用 CSS 绘制，展开时旋转成横线 */
    .nbt-faq .faq-icon {
      position: relative;
      flex: 0 0 22px;
      width: 22px;
      height: 22px;
      border-radius: 50%;
      background: var(--primary-light);
      transition: background 0.2s ease;
    }
    .nbt-faq .faq-icon::before,
    .nbt-faq .faq-icon::after {
      content: "";
      position: absolute;
      top: 50%;
      left: 50%;
      width: 10px;
      height: 2px;
      background: var(--primary);
      border-radius: 2px;
      transform: translate(-50%, -50%);
      transition: transform 0.25s ease, opacity 0.25s ease;
    }
    .nbt-faq .faq-icon::after { transform: translate(-50%, -50%) rotate(90deg); }
    .nbt-faq .faq-item.active .faq-icon { background: var(--primary); }
    .nbt-faq .faq-item.active .faq-icon::before,
    .nbt-faq .faq-item.active .faq-icon::after { background: #fff; }
    .nbt-faq .faq-item.active .faq-icon::after {
      transform: translate(-50%, -50%) rotate(0deg);
      opacity: 0;
    }

    /* 答案区：用 max-height 过渡替代 display:none 的硬切换 */
    .nbt-faq .faq-answer {
      display: block;
      max-height: 0;
      padding: 0 22px;
      overflow: hidden;
      opacity: 0;
      font-size: 16px;
      color: var(--text-gray);
      transition: max-height 0.3s ease, opacity 0.25s ease, padding 0.3s ease;
    }
    .nbt-faq .faq-item.active .faq-answer {
      max-height: 480px;
      padding: 0 22px 18px;
      opacity: 1;
    }
    .nbt-faq .faq-answer p { margin: 0; }

    @media (prefers-reduced-motion: reduce) {
      .nbt-faq .faq-answer,
      .nbt-faq .faq-icon::before,
      .nbt-faq .faq-icon::after { transition: none; }
    }

    @media (max-width: 575.98px) {
      .nbt-faq .faq-question { padding: 16px 18px; font-size: 15px; }
      .nbt-faq .faq-answer { padding: 0 18px; font-size: 15px; }
      .nbt-faq .faq-item.active .faq-answer { max-height: 700px; padding: 0 18px 16px; }
    }