/* ========== 1. CSS Reset ========== */
    *,
    *::before,
    *::after {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      border: 0;
      background: transparent;
      font: inherit;
      color: inherit;
      text-decoration: none;
      list-style: none;
      vertical-align: baseline;
    }

    html {
      -webkit-text-size-adjust: 100%; /* 防止 iOS 横屏自动放大文字 */
      text-size-adjust: 100%;
      -webkit-tap-highlight-color: transparent;
      scroll-behavior: smooth;
      height: 100%;
      /* 无论当前页是否出现滚动条都预留滚动条位置：
         切换长短页面时可用宽度不变，导航/页脚/备案区不会横向偏移 */
      scrollbar-gutter: stable;
    }

    /* 锚点跳转定位补偿：预留吸顶导航高度，避免目标标题被导航遮挡 */
    #business,
    #scenarios,
    #solutions,
    #services,
    #ecosystem {
      scroll-margin-top: var(--nav-h);
    }

    body {
      min-height: 100%;
      line-height: 1.5;
      background-color: #ffffff;
      font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue",
        "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      font-size: 1rem;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

    img,
    picture,
    video,
    canvas,
    svg {
      display: block;
      max-width: 100%;
      height: auto;
    }

    input,
    button,
    textarea,
    select {
      font: inherit;
      color: inherit;
    }

    :focus-visible {
      outline: 2px solid currentColor;
      outline-offset: 2px;
    }

    /* ========== 2. 流式布局基础 ========== */
    :root {
      /* 相对单位 + clamp 实现字号与间距的自适应缩放 */
      --space: clamp(0.75rem, 2vw, 2rem);
      /* 全站统一内容宽度 1140px：所有区域的内容盒都对齐到同一条左右边界 */
      --content-w: 1140px;
      /* 容器外框宽度 = 内容宽 + 左右内边距（各处内边距统一用 --space，故内容宽恒为 1140px） */
      --content-max: calc(var(--content-w) + 2 * var(--space));

      /* 导航栏尺寸与配色 */
      --nav-h: 65px;
      --banner-h: 600px;
      --color-bg: #f6f7f9;
      --color-surface: #ffffff;
      --color-text: #1f2430;
      --color-muted: #5d6675;
      --color-line: rgba(31, 36, 48, 0.1);
      --color-brand: #14a35c;
      --color-brand-soft: rgba(20, 163, 92, 0.1);

      --radius-md: 0.625rem;
      --radius-pill: 999px;
      --shadow-sm: 0 1px 2px rgba(16, 24, 40, 0.04), 0 1px 3px rgba(16, 24, 40, 0.06);
    }

    /* 页面主容器：随视口伸缩，桌面端限制最大宽度 */
    .page {
      width: 100%;
      max-width: var(--content-max);
      min-height: calc(100vh - var(--nav-h) - var(--banner-h));
      min-height: calc(100dvh - var(--nav-h) - var(--banner-h)); /* 移动端地址栏收放时避免跳动 */
      margin-inline: auto;
      padding: var(--space);
      display: flex;
      flex-direction: column;
    }

    /* main 下方新增内容区：高度由内容决定，随内容自适应 */
    .content-area {
      width: 100%;
      max-width: var(--content-max);
      margin-inline: auto;
      padding: var(--space);
      display: flex;
      flex-direction: column;
    }

    /* ========== 能力链区块：标题 + 说明 + 3×3 能力方块 ========== */
    .chain {
      width: 100%;
      padding: 5rem 0;
    }

    .chain__head {
      max-width: var(--content-max);
      margin-inline: auto;
      padding-inline: var(--space);
    }

    .chain__title {
      max-width: 48rem;
      font-size: clamp(1.5rem, 2.4vw, 2.25rem);
      line-height: 1.3;
      font-weight: 700;
      color: var(--color-ink);
    }

    .chain__desc {
      max-width: 48rem;
      margin-top: 1rem;
      font-size: 1.0625rem;
      line-height: 1.8;
      color: var(--color-muted);
    }

    .chain__grid {
      width: 720px; /* 原宽度 1200px 的 60% */
      max-width: 100%; /* 窄屏不溢出容器 */
      flex: 0 1 720px;
      display: grid;
      grid-template-columns: repeat(3, minmax(0, 1fr));
      column-gap: 28px;
      row-gap: 0; /* 行间不留空隙，由分隔线衔接 */
      margin: 0 auto 0 0; /* 靠左对齐 */
      padding-inline: 0;
    }

    /* 去除默认方框：无背景、无边框、无圆角 */
    .chain__box {
      width: 100%;
      padding: 1.5rem 0;
      display: flex;
      flex-direction: column;
    }

    /* 行间分隔线：1px #e5e7eb，横跨整个容器宽度 */
    .chain__divider {
      grid-column: 1 / -1;
      width: 100%;
      height: 1px;
      background: #e5e7eb;
    }

    /* 文字区域占单元格宽度的 70%，右侧 30% 留白；字号随区域缩小同步下调 */
    .chain__box-title {
      width: 70%;
      font-size: 0.9375rem;
      line-height: 1.4;
      font-weight: 600;
      color: var(--color-ink);
    }

    .chain__box-desc {
      width: 70%;
      margin-top: 0.5rem;
      font-size: 0.75rem;
      line-height: 1.75;
      color: var(--color-muted);
    }

    /* 能力区主体：左侧九宫格 + 右侧纵向跑马灯 */
    .chain__body {
      display: flex;
      align-items: flex-start;
      gap: 28px;
      max-width: var(--content-max);
      margin-inline: auto;
      padding-inline: var(--space);
      margin-top: 2.5rem;
    }

    /* 纵向跑马灯：8 个 350×70 方框，自下而上无缝循环 */
    .feature-marquee {
      flex: 0 0 350px;
      width: 350px;
      max-width: 100%;
      height: 424px; /* 可视区约 4 个方框，超出部分裁切 */
      margin-left: auto;
      overflow: hidden;
      /* 顶部、底部线性淡入淡出遮罩，避免边缘生硬截断 */
      -webkit-mask-image: linear-gradient(to bottom, transparent 0, #000 12%, #000 88%, transparent 100%);
      mask-image: linear-gradient(to bottom, transparent 0, #000 12%, #000 88%, transparent 100%);
    }

    .feature-marquee__track {
      display: flex;
      flex-direction: column;
      gap: 22px;
      animation: feature-scroll-up 12s linear infinite;
      will-change: transform; /* 仅动 transform，交给合成层，避免掉帧 */
    }

    .feature-marquee__group {
      display: flex;
      flex-direction: column;
      gap: 22px;
    }

    .feature-marquee__item {
      width: 350px;
      height: 70px;
      display: flex;
      align-items: center;
      gap: 16px;
      padding: 0 24px;
      border: 1px solid #e5e7eb;
      border-radius: 5px;
      background: #ebf3ff; /* 方框底色 */
    }

    .feature-marquee__icon {
      flex: 0 0 40px;
      width: 40px;
      height: 40px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border-radius: 5px;
      background: #ffffff; /* 图标底色改为白色 */
      color: var(--color-brand);
    }

    .feature-marquee__icon svg,
    .feature-marquee__icon-img {
      width: 22px;
      height: 22px;
      display: block;
    }

    .feature-marquee__name {
      font-size: 0.875rem;
      line-height: 1.4;
      font-weight: 400;
      color: var(--color-text);
    }

    /* 位移半个轨道 + 半个间距（11px），保证首尾无缝衔接 */
    @keyframes feature-scroll-up {
      from {
        transform: translateY(0);
      }
      to {
        transform: translateY(calc(-50% - 11px));
      }
    }

    @media (prefers-reduced-motion: reduce) {
      .feature-marquee__track {
        animation: none;
      }
    }

    @media (max-width: 1100px) {
      .chain__body {
        flex-direction: column;
        gap: 2rem;
      }

      .feature-marquee {
        margin-left: 0;
      }
    }

    @media (max-width: 640px) {
      .chain {
        padding: 3rem 0;
      }

      .chain__grid {
        grid-template-columns: 1fr;
      }
    }

    /* ========== 交付方式区块：三行文字 + 5 栏内容（4 条蓝色渐变分隔线） ========== */
    .delivery {
      width: 100%;
      padding: 4rem 0;
    }

    .delivery__head {
      max-width: var(--content-max);
      margin-inline: auto;
      padding-inline: var(--space);
    }

    .delivery__title {
      font-size: 15px;
      line-height: 1.3;
      font-weight: 700;
      color: #0076ff;
    }

    .delivery__subtitle {
      margin-top: 1rem;
      font-size: 36px;
      line-height: 1.5;
      font-weight: 600;
      color: var(--color-ink);
    }

    .delivery__desc {
      max-width: 48rem;
      margin-top: 0.75rem;
      font-size: 1.0625rem;
      line-height: 1.8;
      color: var(--color-muted);
    }

    .delivery__row {
      display: flex;
      align-items: center;
      max-width: var(--content-max);
      margin: 3rem auto 0;
      padding-inline: var(--space);
    }

    .delivery__item {
      flex: 1 1 0;
      min-width: 0;
      min-height: 180px;
      text-align: center;
    }

    .delivery__item-index {
      width: 185px;
      margin-inline: auto;
      text-align: left;
      font-size: 0.875rem;
      font-weight: 600;
      letter-spacing: 0.08em;
      color: #0076ff;
    }

    .delivery__item-title {
      width: 185px;
      margin-inline: auto;
      margin-top: 0.5rem;
      font-size: 1.125rem;
      font-weight: 700;
      text-align: left;
      color: var(--color-text);
    }

    .delivery__item-desc {
      width: 185px;
      margin-inline: auto;
      margin-top: 0.5rem;
      text-align: left;
      font-size: 0.9375rem;
      line-height: 1.7;
      color: var(--color-muted);
    }

    .delivery__divider {
      flex: 0 0 1px;
      align-self: center;
      width: 1px;
      height: 120px;
      background: linear-gradient(to bottom, rgba(19, 106, 250, 0), rgba(19, 106, 250, 0.75) 50%, rgba(19, 106, 250, 0));
    }

    /* 交付方式下方的空白占位：固定 700px，内容整体垂直居中 */
    .delivery-gap {
      flex: 0 0 700px;
      width: 100%;
      height: 700px;
      min-height: 700px;
      max-height: 700px;
      margin: 0;
      padding: 0;
      text-align: center;
      display: flex;
      flex-direction: column;
      justify-content: center; /* 标题、说明与图集整体垂直居中 */
    }

    .delivery-gap__title {
      font-size: 36px;
      font-weight: 700;
      color: var(--color-text);
    }

    .delivery-gap__desc {
      margin-top: 0.5rem;
      font-size: 0.9375rem;
      line-height: 1.7;
      color: var(--color-muted);
    }

    /* 场景图集下方的空白占位：固定 500px，无内边距、无外边距 */
    .gap-500 {
      flex: 0 0 500px;
      width: 100%;
      height: 500px;
      min-height: 500px;
      max-height: 500px;
      margin: 0;
      padding: 0;
      text-align: center;
      display: flex;
      flex-direction: column;
      justify-content: center; /* 内容整体垂直居中 */
    }

    /* 页脚信息区：固定 300px，含左右内边距 */
    .gap-400 {
      flex: 0 0 300px;
      width: 100%;
      height: 300px;
      min-height: 300px;
      max-height: 300px;
      margin: 0;
      padding: 0;
      color: #e1eef9;
      background-color: #f5f5f5;
      display: flex;
      align-items: center;
    }

    /* 页脚内容：左侧品牌信息、右侧业务导航 */
    .footer {
      width: 100%;
      max-width: var(--content-max);
      margin: 0 auto;
      padding: 0 var(--space);
      display: grid;
      grid-template-columns: auto 1fr; /* 左品牌贴边、右侧弹性导航 */
      gap: 3rem;
      align-items: start;
      color: var(--color-text);
      text-align: left;
    }

    /* 左侧品牌列贴容器左边缘 */
    .footer__col--brand {
      justify-self: start;
      min-width: 0;
      text-align: left;
    }

    /* 品牌列下方的联系方式：与品牌简介保持固定间距，并与段落左对齐 */
    .footer__col--brand > .footer__list {
      margin-top: 1rem;
      justify-self: start;
      gap: 7px;
    }

    /* 导航列贴容器右边缘 */
    .footer__nav {
      justify-self: end;
      min-width: 0;
    }

    .footer__nav-title {
      margin-bottom: 0.75rem;
      font-size: 0.875rem;
      font-weight: 600;
      color: var(--color-text);
    }

    .footer__nav .footer__list {
      gap: 7px;
      color: var(--color-muted);
    }

    /* 页脚导航链接：外观与原来的纯文本一致，仅增加可点击与悬停反馈 */
    .footer__nav-link {
      color: inherit;
      text-decoration: none;
      transition: color 0.2s ease;
    }

    .footer__nav-link:hover,
    .footer__nav-link:focus-visible {
      color: #0076ff; /* 悬停/聚焦：品牌蓝，替代原绿色 */
    }

    /* 右侧联系方式列贴容器右边缘，文字左对齐 */
    .footer__list--contact {
      justify-self: end;
      min-width: 0;
      text-align: left;
    }

    .footer__brand {
      display: flex;
      align-items: center;
      gap: 0.75rem;
    }

    .footer__logo {
      width: 30px;
      height: 30px;
      flex: 0 0 30px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      color: #0076ff; /* 页脚品牌图标：使用品牌蓝，替代原绿色 */
      object-fit: contain;
    }

    .footer__logo svg {
      width: 100%;
      height: 100%;
    }

    .footer__brand-name {
      font-size: 1.125rem;
      font-weight: 700;
      color: var(--color-text);
    }

    .footer__line {
      margin-top: 0.5rem;
      font-size: 0.8125rem;
      line-height: 1.6;
      color: var(--color-muted);
    }

    .footer__list {
      margin: 0;
      padding: 0;
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 0.75rem;
      font-size: 0.875rem;
      line-height: 1.5;
    }

    .footer__list--contact {
      font-size: 0.8125rem;
      color: var(--color-muted);
    }

    .footer__item {
      display: flex;
      align-items: center;
      gap: 0.5rem;
    }

    /* 联系方式行：图标与文字整体靠左 */
    .footer__list--contact .footer__item {
      justify-content: flex-start;
    }

    .footer__icon {
      width: 15px;
      height: 15px;
      flex: 0 0 15px;
      display: block;
    }

    /* 地址文字固定 200px 宽、20px 高，超出部分在列内换行 */
    .footer__address {
      width: 200px;
      height: 20px;
      text-align: left;
    }

    /* 窄屏：保持左中右三列结构，仅收窄间距与字号 */
    @media (max-width: 900px) {
      .footer {
        /* 内边距沿用 --space，保证窄屏下内容边界与其它区块一致 */
        gap: 1.5rem;
      }

      .footer__line {
        font-size: 0.75rem;
      }

      .footer__list--contact {
        font-size: 0.75rem;
      }
    }

    /* ========== 备案信息：1px 分隔线 + 居中单行 ========== */
    .beian {
      width: 100%;
      background: #ffffff;
      overflow-x: auto;          /* 极窄屏时整行横向滚动，避免页面溢出 */
      overflow-y: hidden;
    }

    .beian__line {
      width: 100%;
      height: 1px;
      background: #e5e7eb;
    }

    .beian__inner {
      width: max-content;
      margin: 0 auto;            /* 宽度足够时居中，不足时从左侧可滚动 */
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 0.5rem;
      padding: 0.75rem 1rem;
      line-height: 24px;
      font-size: 12px;
      color: #6b7280;
      white-space: nowrap;
    }

    .beian__sep {
      color: #d1d5db;
    }

    .beian__link,
    .beian__police {
      color: #6b7280;
      text-decoration: none;
    }

    .beian__link:hover,
    .beian__police:hover {
      color: #1f2430;
    }

    .beian__police {
      display: inline-flex;
      align-items: center;
      gap: 0.375rem;
    }

    .beian__police img {
      width: 16px;
      height: 16px;
      display: block;
      flex: 0 0 16px;
    }

    /* ========== 伙伴跑马灯：两行 160×72 白色方框，无缝匀速滚动 ========== */
    .marquee {
      /* 与其它区块共用同一左右内边距，窄屏时内容边界仍与正文对齐 */
      width: calc(100% - 2 * var(--space));
      max-width: var(--content-w);
      margin: 2.5rem auto 0;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }

    .marquee__row {
      overflow: hidden;
      padding-block: 12px; /* 给方框上下阴影留出显示空间 */
    }

    .marquee__track {
      display: flex;
      width: max-content;
      will-change: transform;
    }

    .marquee__track--right {
      animation: marquee-right 40s linear infinite;
    }

    .marquee__track--left {
      animation: marquee-left 40s linear infinite;
    }

    .marquee__item {
      flex: 0 0 160px;
      width: 160px;
      height: 72px;
      margin-right: 16px;      /* 用外边距代替 gap，保证 -50% 位移无缝 */
      display: flex;
      align-items: center;
      justify-content: center;
      background: #ffffff; /* 纯白卡面，与阴影形成明暗对比 */
      border: 0;
      border-radius: 6px;
      overflow: hidden; /* 裁掉图片矩形边角，保证圆角始终生效 */
      box-shadow: 0 0 10px rgba(16, 24, 40, 0.16); /* 四周均匀阴影，白底上可见 */
    }

    .marquee__item img {
      display: block;
      max-width: 100%;
      max-height: 100%;
      object-fit: contain;
    }

    /* 图片加载失败时的占位 */
    .marquee__item.is-fallback::after {
      content: "LOGO";
      font-size: 0.75rem;
      font-weight: 600;
      letter-spacing: 0.08em;
      color: #9aa3af;
    }

    @keyframes marquee-right {
      from { transform: translateX(-50%); }
      to { transform: translateX(0); }
    }

    @keyframes marquee-left {
      from { transform: translateX(0); }
      to { transform: translateX(-50%); }
    }

    @media (prefers-reduced-motion: reduce) {
      .marquee__track--right,
      .marquee__track--left {
        animation: none;
      }
    }

    /* ========== 场景图集：120px 折叠、550px 展开的横向手风琴 ========== */
    .gallery {
      display: flex;
      gap: 16px;
      justify-content: center;
      /* 与其它区块共用同一左右内边距，窄屏时内容边界仍与正文对齐 */
      width: calc(100% - 2 * var(--space));
      max-width: var(--content-w);
      margin-inline: auto;
      margin-top: 2.5rem;
    }

    .gallery__item {
      position: relative;
      flex: 0 1 auto;      /* 空间不足时等比收缩，避免溢出 */
      width: 120px;
      min-width: 0;        /* 允许收缩到容器内，不撑破布局 */
      height: 480px;
      margin: 0;
      overflow: hidden;
      border-radius: 12px;
      background: #101822;
      cursor: pointer;
      transition: width 0.5s cubic-bezier(0.22, 0.61, 0.36, 1);
    }

    .gallery__item.is-active {
      width: 550px;
    }

    .gallery__img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: transform 0.5s cubic-bezier(0.22, 0.61, 0.36, 1);
    }

    .gallery__item.is-active .gallery__img {
      transform: scale(1.02);
    }

    /* 图面上的文字层：标题 + 正文 + 虚线 + 三项列表 */
    .gallery__panel {
      position: absolute;
      inset: 0;
      display: flex;
      flex-direction: column;
      justify-content: center;
      gap: 1rem;
      padding: 2.5rem;
      color: #ffffff;
      text-align: left;
      background: linear-gradient(115deg, rgba(18, 74, 158, 0.58), rgba(18, 74, 158, 0.12));
    }

    /* 收起状态：只保留标题，正文、虚线与列表隐藏 */
    .gallery__item:not(.is-active) .gallery__panel {
      padding: 1rem;
    }

    .gallery__item:not(.is-active) .gallery__panel-desc,
    .gallery__item:not(.is-active) .gallery__panel-line,
    .gallery__item:not(.is-active) .gallery__panel-list {
      display: none;
    }

    .gallery__panel-title {
      font-size: 1.75rem;
      font-weight: 700;
      letter-spacing: 0.04em;
    }

    .gallery__panel-desc {
      max-width: 30rem;
      font-size: 0.9375rem;
      line-height: 1.7;
      color: rgba(255, 255, 255, 0.82);
    }

    .gallery__panel-line {
      width: 100%;
      height: 0;
      border-top: 1px dashed rgba(255, 255, 255, 0.45);
    }

    .gallery__panel-list {
      display: flex;
      flex-direction: column;
      gap: 0.4rem;
      font-size: 0.875rem;
      line-height: 1.7;
      color: rgba(255, 255, 255, 0.9);
    }

    .gallery__caption {
      position: absolute;
      inset: auto 0 0 0;
      display: flex;
      flex-direction: column;
      gap: 0.25rem;
      padding: 1rem;
      text-align: left;
      color: #ffffff;
      background: linear-gradient(to top, rgba(12, 18, 28, 0.85), rgba(12, 18, 28, 0));
    }

    .gallery__no {
      font-size: 0.75rem;
      font-weight: 600;
      letter-spacing: 0.08em;
    }

    .gallery__name {
      font-size: 0.9375rem;
      font-weight: 700;
      white-space: nowrap;
    }

    @media (prefers-reduced-motion: reduce) {
      .gallery__item,
      .gallery__img {
        transition: none;
      }
    }

    @media (max-width: 640px) {
      .delivery {
        padding: 3rem 0;
      }

      .delivery__row {
        flex-direction: column;
        gap: 2rem;
      }

      .delivery__divider {
        width: 120px;
        height: 1px;
        flex-basis: 1px;
        background: linear-gradient(to right, rgba(19, 106, 250, 0), rgba(19, 106, 250, 0.75) 50%, rgba(19, 106, 250, 0));
      }

      .delivery__item {
        width: 100%;
        min-height: 0;
      }
    }

    /* 内容区标题与正文：标题层级突出，正文常规排版 */
    .about__eyebrow {
      margin-bottom: 0.5rem;
      font-size: 15px;
      line-height: 1.4;
      font-weight: 700;
      color: #0076ff;
    }

    .about__title {
      max-width: 48rem;
      font-size: clamp(1.5rem, 2.4vw, 2.25rem);
      line-height: 1.3;
      font-weight: 700;
      letter-spacing: -0.01em;
      color: var(--color-text);
    }

    .about__desc {
      max-width: 52rem;
      margin-top: clamp(0.75rem, 1.6vw, 1.25rem);
      font-size: clamp(0.9375rem, 1.1vw, 1.0625rem);
      line-height: 1.8;
      color: var(--color-muted);
    }

    /* 卡片容器：三列等宽铺满，水平/垂直间距统一 28px */
    .about__grid {
      margin-top: clamp(1.5rem, 3vw, 2.5rem);
      display: grid;
      grid-template-columns: repeat(3, minmax(0, 1fr));
      gap: 28px;
      justify-content: center;
    }

    .about__card {
      width: 100%;
      height: 220px;
      border: 1px solid var(--color-line);
      border-radius: var(--radius-md);
      background: var(--color-surface);
      box-shadow: var(--shadow-sm);
    }

    /* 中等宽度：两列等宽铺满 */
    @media (max-width: 1080px) {
      .about__grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
      }
    }

    /* 手机：单列铺满 */
    @media (max-width: 720px) {
      .about__grid {
        grid-template-columns: minmax(0, 1fr);
        gap: 20px;
      }
    }

    /* 超窄屏：单列铺满，高度按内容自适应，避免文字被截断 */
    @media (max-width: 400px) {
      .about__card {
        height: auto;
        min-height: 220px;
      }
    }

    /* 云计算与基础设施：标题 + 描述 + 4 个自适应宽度、固定高度的方框 */
    .cloud {
      margin-top: clamp(2rem, 4vw, 3.5rem);
    }

    /* 区块序号：小字号，与标题保持紧凑的视觉层级 */
    .cloud__index {
      margin-bottom: 0.5rem;
      font-size: 11px;
      line-height: 1.4;
      letter-spacing: 0.08em;
      color: var(--color-muted);
    }

    .cloud__title {
      font-size: 22px;
      line-height: 1.35;
      font-weight: 700;
      letter-spacing: -0.01em;
      color: var(--color-text);
    }

    .cloud__desc {
      max-width: 52rem;
      margin-top: 0.75rem;
      font-size: 14px;
      line-height: 1.8;
      color: var(--color-muted);
    }

    /* 四个方框水平排列，间距均匀；宽度随文字自适应，高度固定 26px */
    .cloud__tags {
      margin-top: clamp(1rem, 2vw, 1.5rem);
      display: flex;
      flex-wrap: wrap;
      align-items: center;
      justify-content: flex-start;
      gap: clamp(0.75rem, 2vw, 1.5rem);
    }

    .cloud__tag {
      height: 26px;
      padding: 0 0.75rem;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      white-space: nowrap;
      font-size: 0.8125rem;
      line-height: 1;
      color: var(--color-text);
      border: 1px solid var(--color-line);
      border-radius: 0.375rem;
      background: var(--color-surface);
      box-shadow: var(--shadow-sm);
    }

    /* 放入 330×280 卡片后的内距、垂直居中与紧凑排版 */
    .about__card--cloud {
      position: relative; /* 作为悬停淡光的定位参照 */
      padding: 1rem;
      display: flex;
      flex-direction: column;
      justify-content: flex-start;
      align-items: center;
      /* 高度固定为 220px：内容不足时由下方 auto 外边距垂直居中，
         内容超高时在 .cloud 内部纵向滚动，避免撑破方框或裁切文字 */
      overflow: hidden; /* 裁切淡光，保证滑动路径不超出方框可视区域 */
      border-top-color: var(--color-line);
      transition: border-top-color 0.42s ease-in-out;
    }

    /* 悬停淡光：默认隐藏，悬停时从左向右滑过；中心高亮、两端透明，浅蓝→深蓝渐变 */
    .about__card--cloud::after {
      content: "";
      position: absolute;
      inset: 0;
      z-index: 0; /* 位于内容之下 */
      pointer-events: none;
      opacity: 0;
      transform: translateX(-100%);
      background-image: linear-gradient(
        100deg,
        rgba(0, 118, 255, 0) 0%,
        rgba(126, 192, 255, 0.22) 30%,
        rgba(0, 118, 255, 0.3) 50%,
        rgba(126, 192, 255, 0.22) 70%,
        rgba(0, 118, 255, 0) 100%
      );
      /* 移出时：透明度平滑淡出；位置瞬时复位（复位瞬间光带已在方框外侧，
         被 overflow:hidden 完全裁切，因此不会出现“反向扫回”的二次闪光或残留） */
      transition: opacity 0.3s ease-in-out, transform 0s linear;
    }

    .about__card--cloud:hover {
      border-top-color: #0076ff; /* 顶部边框切换为指定蓝色 */
      border-top-width: 3px; /* 悬停时顶部蓝线加粗至 3px；border-box 下外框尺寸不变 */
    }

    .about__card--cloud:hover::after {
      opacity: 1;
      transform: translateX(100%);
      transition: opacity 0.3s ease-in-out, transform 0.45s ease-in-out;
    }

    .about__card--cloud .cloud {
      position: relative;
      z-index: 1; /* 内容位于淡光之上，光效不遮挡文字 */
      width: 100%;
      max-height: 100%;
      /* 上下 auto 外边距：有剩余空间时垂直居中，空间不足时自动归零并启用滚动 */
      margin-block: auto;
      overflow-y: auto;
      /* 不使用 overscroll-behavior: contain：
         它会把卡片作为滚动链的终点，即使卡片本身没有可滚动内容，
         鼠标停在卡片上时滚轮也不再传递给页面，导致页面无法继续向下滚动 */
      scrollbar-width: thin;
    }

    .about__card--cloud .cloud::-webkit-scrollbar {
      width: 4px;
    }

    .about__card--cloud .cloud::-webkit-scrollbar-thumb {
      border-radius: 2px;
      background: var(--color-line);
    }

    .about__card--cloud .cloud__tags {
      /* 随卡片高度压缩到 220px，标签与描述之间的间距同步自适应 */
      margin-top: clamp(0.75rem, 2.4vw, 1.875rem);
      gap: 8px;
    }

    /* ========== 3. 顶部导航栏（固定高度 65px，左右两端对齐） ========== */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 100;
      height: var(--nav-h);
      background-color: rgba(255, 255, 255, 0.92);
      border-bottom: 1px solid var(--color-line);
      -webkit-backdrop-filter: blur(12px);
      backdrop-filter: blur(12px);
    }

    .nav {
      position: relative; /* 作为移动端折叠面板的定位参照 */
      height: 100%;
      max-width: var(--content-max);
      margin-inline: auto;
      /* 内边距与各内容区一致，导航内容与正文左右边界对齐 */
      padding-inline: var(--space);
      display: flex;
      align-items: center;
      gap: clamp(1rem, 3vw, 2rem);
    }

    /* 左侧品牌区：图标 + 品牌文字，整块可点击返回首页 */
    .brand {
      display: inline-flex;
      align-items: center;
      gap: 0.625rem;
      flex-shrink: 0;
      border-radius: var(--radius-md);
      transition: opacity 0.2s ease, transform 0.12s ease;
    }
    .brand:hover {
      opacity: 0.85;
    }
    .brand:active {
      transform: translateY(1px);
    }
    .brand__logo {
      width: 2rem;
      height: 2rem;
      display: grid;
      place-items: center;
      flex-shrink: 0;
      border-radius: 0.5rem;
      color: #fff;
      background: #0076ff;
      box-shadow: 0 2px 6px rgba(0, 118, 255, 0.28);
    }
    .brand__logo svg {
      width: 1.125rem;
      height: 1.125rem;
    }
    img.brand__logo {
      display: block;
      border-radius: 0;
      background: transparent;
      box-shadow: none;
      object-fit: contain;
    }
    .brand__name {
      font-size: 1.0625rem;
      font-weight: 600;
      letter-spacing: 0.02em;
      color: var(--color-text);
      white-space: nowrap;
    }

    /* 中部标签 + 右侧按钮的容器 */
    .nav__menu {
      flex: 1;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 1rem;
      min-width: 0;
    }

    /* 中间导航标签：统一间距、悬停高亮、激活态 */
    .nav__links {
      display: flex;
      align-items: center;
      gap: clamp(0.25rem, 1vw, 0.75rem);
      margin-inline: auto;
    }
    .nav__link {
      display: inline-flex;
      align-items: center;
      padding: 0.5rem 0.875rem;
      border-radius: 8px;
      font-size: 0.9375rem;
      color: var(--color-muted);
      white-space: nowrap;
      transition: color 0.18s ease, background-color 0.18s ease, transform 0.12s ease;
    }
    .nav__link:hover {
      /* 仅悬停时呈现激活态：蓝色文字 + 淡蓝底 */
      color: #0076ff;
      background-color: rgba(0, 118, 255, 0.1);
    }
    .nav__link:active {
      transform: scale(0.97);
    }

    /* 右侧按钮区：与普通标签区分视觉权重 */
    .nav__actions {
      display: flex;
      align-items: center;
      gap: 0.625rem;
      flex-shrink: 0;
    }
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 0.5rem 1rem;
      border-radius: 8px;
      font-size: 0.875rem;
      font-weight: 500;
      white-space: nowrap;
      transition: color 0.18s ease, background-color 0.18s ease, border-color 0.18s ease,
        box-shadow 0.18s ease, transform 0.12s ease;
    }
    .btn:active {
      transform: scale(0.97);
    }
    .btn--ghost {
      color: var(--color-text);
      background-color: var(--color-surface);
      border: 1px solid var(--color-line);
    }
    .btn--primary {
      color: #fff;
      background: #0076ff;
      box-shadow: 0 2px 8px rgba(0, 118, 255, 0.28);
    }
    .btn--primary:hover {
      box-shadow: 0 4px 14px rgba(0, 118, 255, 0.36);
      filter: brightness(1.03);
    }

    /* 移动端菜单开关：桌面端隐藏 */
    .nav__toggle {
      display: none;
      align-items: center;
      justify-content: center;
      flex-direction: column;
      gap: 4px;
      width: 2.5rem;
      height: 2.5rem;
      margin-left: auto;
      flex-shrink: 0;
      border-radius: var(--radius-md);
      border: 1px solid var(--color-line);
      background-color: var(--color-surface);
      cursor: pointer;
      transition: background-color 0.18s ease, transform 0.12s ease;
    }
    .nav__toggle:hover {
      background-color: rgba(31, 36, 48, 0.04);
    }
    .nav__toggle:active {
      transform: scale(0.95);
    }
    .nav__toggle-bar {
      width: 1.125rem;
      height: 1.5px;
      border-radius: 1px;
      background-color: var(--color-text);
      transition: transform 0.22s ease, opacity 0.22s ease;
    }
    /* 展开时三条横线变为关闭图标 */
    .nav__toggle[aria-expanded="true"] .nav__toggle-bar:nth-child(1) {
      transform: translateY(5.5px) rotate(45deg);
    }
    .nav__toggle[aria-expanded="true"] .nav__toggle-bar:nth-child(2) {
      opacity: 0;
    }
    .nav__toggle[aria-expanded="true"] .nav__toggle-bar:nth-child(3) {
      transform: translateY(-5.5px) rotate(-45deg);
    }

    /* 移动端折叠：菜单收进下拉面板 */
    @media (max-width: 900px) {
      .nav__toggle {
        display: inline-flex;
      }
      .nav__menu {
        position: absolute;
        top: 100%;
        inset-inline: 0;
        display: none;
        flex-direction: column;
        align-items: stretch;
        gap: 0.75rem;
        padding: 1rem clamp(1rem, 4vw, 2.5rem) 1.25rem;
        background-color: var(--color-surface);
        border-bottom: 1px solid var(--color-line);
        box-shadow: var(--shadow-sm);
      }
      .nav__menu.is-open {
        display: flex;
      }
      .nav__links {
        flex-direction: column;
        align-items: stretch;
        gap: 0.25rem;
        margin-inline: 0;
      }
      .nav__link {
        justify-content: flex-start;
        padding: 0.625rem 0.75rem;
        border-radius: 8px;
      }
      .nav__actions {
        gap: 0.5rem;
      }
      .btn {
        flex: 1;
      }
    }

    /* ========== 4. Banner 展示区（全宽，固定高度 600px） ========== */
    .banner {
      position: relative; /* 作为文字绝对定位的参照 */
      width: 100%;
      height: var(--banner-h);
      /* 文字层居中：两行文字整体水平、垂直居中 */
      display: flex;
      align-items: center;
      justify-content: center;
      /* 图片等比缩放并裁切填满，不变形、不留白 */
      background-color: #0d3b2a; /* 图片加载期间的兜底底色 */
      background-image: url("./uploads/banner.jpg"); /* 优化版：2560px 宽、约 134KB */
      background-repeat: no-repeat;
      background-position: center center;
      background-size: cover;
      overflow: hidden;
    }

    /* Banner 文字：两行独立文本，采用绝对定位，可通过 X(left)、Y(top) 数值精确调整位置 */
    .banner__copy {
      position: absolute;
      inset: 0;
      text-align: center;
    }

    /* 第一行：65px 加粗 #0076ff；窄屏按 8vw 收缩，避免超出裁切 */
    .banner__line--brand {
      position: absolute;
      left: 600px; /* X：水平位置 */
      top: 220px; /* Y：垂直位置 */
      transform: translate(-50%, -50%); /* 以文字中心对齐坐标点 */
      margin: 0;
      font-size: min(65px, 8vw);
      font-weight: 700;
      line-height: 1.15;
      color: #0076ff;
    }

    /* 第二行：60px 纯黑；窄屏按 7.4vw 收缩，保证完整显示 */
    .banner__line--plain {
      position: absolute;
      left: 650px; /* X：水平位置 */
      top: 58%; /* Y：垂直位置 */
      transform: translate(-50%, -50%);
      margin: 0;
      font-size: min(60px, 7.4vw);
      font-weight: 400;
      line-height: 1.15;
      color: #000000;
    }

    /* ========== 5. 能力底座区块（左侧文案 + 右侧数据流示意图） ========== */
    .capability {
      display: grid;
      grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.4fr);
      align-items: center;
      gap: clamp(1.5rem, 5vw, 4rem);
      padding-block: clamp(2.5rem, 6vw, 4rem) clamp(3rem, 7vw, 5rem);
    }

    .capability__copy {
      max-width: 33rem;
    }

    /* 主标题：字号随视口缩放，字重 700，行高 1.25 */
    .capability__title {
      margin: 0;
      font-size: clamp(1.75rem, 3vw, 2.1875rem);
      font-weight: 700;
      line-height: 1.25;
      letter-spacing: -0.01em;
      color: var(--color-text);
    }

    /* 正文：1.9 倍行高保证长段落可读性 */
    .capability__desc {
      margin: clamp(1rem, 2vw, 1.5rem) 0 0;
      font-size: clamp(0.9375rem, 1.05vw, 1.0625rem);
      font-weight: 400;
      line-height: 1.9;
      color: var(--color-muted);
    }

    /* 右侧示意图容器：三列布局，SVG 连接线绝对定位铺满 */
    .capability__stage {
      --cap-ink: #1b2030;
      --cap-accent: #3b46e0;
      position: relative;
      display: grid;
      width: 600px;
      max-width: 100%;
      justify-self: end; /* 两列布局中整体靠右对齐（原来被误改为 center，导致右侧多出居中留白） */
      /* 三列宽度与各自卡片一致(78px / 210px / 140px)，列间距即为卡片间距 44px */
      grid-template-columns: 4.875rem 210px 140px;
      justify-content: center; /* 三列内容在自身 600px 内居中，抵消左右内边距差 */
      align-items: center;
      gap: 44px;
      padding: clamp(1rem, 2.5vw, 1.9rem);
      border-radius: 1.25rem;
      background: linear-gradient(180deg, #f8f9fc 0%, #f1f3f8 100%);
      isolation: isolate;
    }

    .stage__links {
      position: absolute;
      inset: 0;
      z-index: 0;
      width: 100%;
      height: 100%;
      overflow: visible;
      pointer-events: none;
    }

    .stage__col {
      position: relative;
      z-index: 1;
      display: flex;
      flex-direction: column;
      gap: clamp(0.5rem, 1.4vw, 0.85rem);
      min-width: 0;
    }

    .stage__label {
      /* 标签移出文档流，使左列的居中基准与卡片一致，左右中线因此水平对齐 */
      position: absolute;
      left: 0;
      bottom: calc(100% + 0.35rem);
      margin: 0;
      font-size: 0.6875rem;
      font-weight: 600;
      letter-spacing: 0.16em;
      color: #5b6bd6;
      /* 左列收窄到 78px 后保持标签单行，允许在列右侧留白处溢出 */
      white-space: nowrap;
    }

    /* 左侧来源卡片 */
    .app-card {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 0.4rem;
      padding: 0.7rem 0.5rem 0.55rem;
      border: 2px solid #b9bdf7;
      border-radius: 0.85rem;
      background: var(--color-surface);
      box-shadow: 0 3px 8px rgba(59, 70, 224, 0.1);
      color: var(--cap-ink);
      transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
    }

    .app-card:hover {
      transform: translateY(-2px);
      border-color: #6d75ef;
      box-shadow: 0 8px 18px rgba(59, 70, 224, 0.16);
    }

    .app-card__icon {
      display: grid;
      place-items: center;
      width: 1.9rem;
      height: 1.9rem;
      border-radius: 999px;
      background: #4f57e8;
      color: #fff;
    }

    .app-card__icon svg {
      width: 1rem;
      height: 1rem;
    }

    .app-card__name {
      font-size: 0.8125rem;
      line-height: 1.2;
      color: var(--cap-ink);
    }

    /* 三张来源卡片宽度固定为 78px（含边框与内边距），高度、内边距、对齐保持不变 */
    .stage__col--app .app-card {
      width: 78px;
    }

    /* 中央网关卡片 */
    .gateway {
      position: relative;
      z-index: 2;
      width: 210px;
      padding: clamp(0.9rem, 2vw, 1.4rem) clamp(0.8rem, 1.6vw, 1.2rem);
      border: 1.5px solid #b9bdf7;
      border-radius: 1rem;
      background: var(--color-surface);
      box-shadow: 0 14px 30px rgba(50, 58, 160, 0.1);
      text-align: center;
    }

    .gateway__badge {
      display: inline-flex;
      align-items: center;
      gap: 0.4rem;
      padding: 0.3rem 0.7rem;
      border-radius: 999px;
      background: #fff;
      box-shadow: 0 3px 10px rgba(20, 24, 60, 0.14);
      font-size: 0.8125rem;
      font-weight: 600;
      color: var(--cap-ink);
    }

    .gateway__logo {
      width: 0.95rem;
      height: 0.95rem;
      color: var(--cap-accent);
    }

    .gateway__eyebrow {
      margin: 0.7rem 0 0;
      font-size: 0.625rem;
      font-weight: 500;
      letter-spacing: 0.3em;
      color: #98a0b4;
    }

    .gateway__list {
      display: grid;
      gap: 0.5rem;
      margin: 0.85rem 0 0;
      padding: 0;
      list-style: none;
    }

    .gateway__item {
      width: 170px;
      justify-self: center;
      padding: 0.5rem 0.6rem;
      border: 1px solid #dfe1fb;
      border-radius: 0.6rem;
      background: #f8f8ff;
      color: #3c4154;
      font-size: 0.78125rem;
      line-height: 1.4;
    }

    /* 右侧目标面板 */
    .stage__col--targets {
      display: grid;
      gap: clamp(0.55rem, 1.4vw, 0.8rem);
    }

    .target-card {
      width: 140px;
      justify-self: center; /* 固定宽度后在列内居中 */
      padding: 0.6rem 0.55rem 0.65rem;
      border: 1.5px solid #c7c9f6;
      border-radius: 0.85rem;
      background: var(--color-surface);
      box-shadow: 0 3px 10px rgba(40, 45, 120, 0.07);
    }

    .target-card__title {
      margin: 0 0 0.45rem;
      font-size: 0.8125rem;
      font-weight: 600;
      text-align: center;
      color: var(--cap-ink);
    }

    .target-card__grid {
      display: grid;
      grid-template-columns: repeat(3, minmax(0, 1fr));
      gap: 0.35rem;
    }

    .target-card__grid--two {
      grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    /* Agents 卡片（5 个图标）：6 栏基准，前 3 格各占 2 栏；
       末行 2 个图标（第 4、5 格）占第 2~5 栏，左右各留 1 栏，整体水平居中。
       每栏 16px + 3px 列间距，使跨 2 栏的格子正好 35px 宽、相邻格子水平间距恒为 3px */
    .target-card[data-link-node="agent-tools"] .target-card__grid {
      grid-template-columns: repeat(6, 16px);
      column-gap: 3px;
      justify-content: center;
    }

    .target-card[data-link-node="agent-tools"] .target-card__grid > .target-card__cell:nth-child(-n + 3) {
      grid-column: span 2;
    }

    .target-card[data-link-node="agent-tools"] .target-card__grid > .target-card__cell:nth-child(4) {
      grid-column: 2 / span 2;
    }

    .target-card[data-link-node="agent-tools"] .target-card__grid > .target-card__cell:nth-child(5) {
      grid-column: 4 / span 2;
    }

    .target-card__cell {
      display: grid;
      place-items: center;
      aspect-ratio: 1 / 1;
      border-radius: 0.4rem;
      background: #fff;
      box-shadow: 0 1px 3px rgba(20, 24, 60, 0.14), inset 0 0 0 1px rgba(20, 24, 60, 0.05);
    }

    .target-card__cell svg {
      width: 56%;
      height: 56%;
    }

    /* LLMs 卡片图标格：固定 35×35，在各自栅格列内居中 */
    .target-card[data-link-node="llms"] .target-card__cell {
      width: 35px;
      height: 35px;
      aspect-ratio: auto;
      justify-self: center;
    }

    /* LLMs 卡片栅格：轨道固定 35px、列间距 3px，整体在卡片内居中 */
    .target-card[data-link-node="llms"] .target-card__grid {
      grid-template-columns: repeat(3, 35px);
      column-gap: 3px;
      justify-content: center;
    }

    /* 外部 SVG 图标（uploads/icon1.svg）：按原始宽高比缩放，避免拉伸 */
    .target-card__cell .target-card__img {
      width: 72%;
      height: auto;
      aspect-ratio: auto;
      object-fit: contain;
      display: block;
    }

    /* LLMs 卡片第 1 个图标（uploads/icon1.svg）：固定为 27×25 */
    .target-card[data-link-node="llms"] .target-card__cell:nth-child(1) .target-card__img {
      width: 27px;
      height: 25px;
    }

    /* LLMs 卡片第 2/3/5 个图标（uploads/icon2、icon3、icon5.svg）：固定为 25×25 */
    .target-card[data-link-node="llms"] .target-card__cell:nth-child(2) .target-card__img,
    .target-card[data-link-node="llms"] .target-card__cell:nth-child(3) .target-card__img,
    .target-card[data-link-node="llms"] .target-card__cell:nth-child(5) .target-card__img {
      width: 25px;
      height: 25px;
    }

    /* LLMs 卡片第 4 个图标（uploads/icon4.svg）：固定为 25×25 */
    .target-card[data-link-node="llms"] .target-card__cell:nth-child(4) .target-card__img {
      width: 25px;
      height: 25px;
    }

    /* LLMs 卡片第 6 个图标（uploads/icon6.svg）：固定为 25×21 */
    .target-card[data-link-node="llms"] .target-card__cell:nth-child(6) .target-card__img {
      width: 25px;
      height: 21px;
    }

    /* MCPs 卡片：固定高度 125px（容纳 2×35px 图标格 + 间距），标题与图标网格按剩余空间自适应 */
    .target-card[data-link-node="mcps"] {
      display: flex;
      flex-direction: column;
      height: 125px;
      min-height: 0;
      overflow: hidden;
    }

    /* MCPs 图标网格：占满剩余高度，两行各 35px 并在剩余空间内垂直居中 */
    .target-card[data-link-node="mcps"] .target-card__grid {
      flex: 1 1 auto;
      min-height: 0;
      grid-template-rows: repeat(2, 35px);
      align-content: center;
      justify-content: center;
    }

    /* MCPs 卡片 4 个图标单元格：固定为 35×35 */
    .target-card[data-link-node="mcps"] .target-card__cell {
      width: 35px;
      height: 35px;
      aspect-ratio: auto;
      min-height: 0;
    }

    /* MCPs 2×2 网格：列宽锁定为 35px，使水平间距等于 gap 5.6px，并整体居中 */
    .target-card[data-link-node="mcps"] .target-card__grid--two {
      grid-template-columns: repeat(2, 35px);
      justify-content: center;
    }

    /* 图标尺寸随视口轻微缩放，但不撑破单元格 */
    .target-card[data-link-node="mcps"] .target-card__cell svg {
      width: clamp(1.125rem, 1.6vw + 0.6rem, 1.6rem);
      height: auto;
      aspect-ratio: 1 / 1;
    }

    /* MCPs 卡片外部图标（uploads/icon7~icon10.svg）：固定 25×25，等比缩放不拉伸 */
    .target-card[data-link-node="mcps"] .target-card__cell .target-card__img {
      width: 25px;
      height: 25px;
      object-fit: contain;
    }

    /* Agents 卡片图标格：固定 35×35，在各自栅格区域内居中 */
    .target-card[data-link-node="agent-tools"] .target-card__cell {
      width: 35px;
      height: 35px;
      aspect-ratio: auto;
      justify-self: center;
    }

    /* Agents 卡片外部图标（uploads/icon11~icon15.svg）：固定 25×25，等比缩放不拉伸 */
    .target-card[data-link-node="agent-tools"] .target-card__cell .target-card__img {
      width: 25px;
      height: 25px;
      object-fit: contain;
    }

    /* SVG 连接线：底层实线 + 上层流动虚线 + 端口脉冲 */
    .cap-link {
      fill: none;
      stroke: #3b46e0;
      stroke-width: 1.4;
      opacity: 0.7;
    }

    .cap-flow {
      fill: none;
      stroke: #6f78ff;
      stroke-width: 1.6;
      stroke-linecap: round;
      stroke-dasharray: 3 9;
      opacity: 0.85;
    }

    .cap-port {
      fill: #fff;
      stroke: #3b46e0;
      stroke-width: 1.4;
    }

    .cap-link.is-hot {
      stroke: #2530d6;
      opacity: 1;
    }

    .cap-flow.is-hot {
      stroke: #2b34d6;
    }

    @media (prefers-reduced-motion: no-preference) {
      .cap-flow {
        animation: cap-dash 2.2s linear infinite;
      }
      .cap-port {
        animation: cap-port-pulse 2.6s ease-in-out infinite;
      }
      .gateway__item {
        animation: cap-pill 3.2s ease-in-out infinite;
      }
      .gateway__item:nth-child(2) { animation-delay: 0.4s; }
      .gateway__item:nth-child(3) { animation-delay: 0.8s; }
      .gateway__item:nth-child(4) { animation-delay: 1.2s; }
    }

    /* 离屏或切到后台时暂停全部循环动画 */
    .capability__stage[data-paused] .cap-flow,
    .capability__stage[data-paused] .cap-port,
    .capability__stage[data-paused] .gateway__item {
      animation-play-state: paused;
    }

    @keyframes cap-dash {
      to { stroke-dashoffset: -12; }
    }

    @keyframes cap-port-pulse {
      50% { opacity: 0.35; }
    }

    @keyframes cap-pill {
      0%, 70%, 100% { background: #f8f8ff; border-color: #dfe1fb; }
      15% { background: #ecebff; border-color: #b9bdf7; }
    }

    /* 平板及以下：文案与示意图上下排列 */
    @media (max-width: 980px) {
      .capability {
        grid-template-columns: 1fr;
        gap: clamp(1.75rem, 4vw, 2.5rem);
      }
      .capability__copy {
        max-width: 40rem;
      }
      /* 单列堆叠时示意图独占一行，改为水平居中，避免靠右留下大片不对称空白 */
      .capability__stage {
        justify-self: center;
      }
    }

    /* 手机：示意图改为纵向堆叠，来源卡片横向排列 */
    @media (max-width: 640px) {
      .capability__stage {
        /* 固定 600px 宽度会让单列网格的 min-content 撑到 600px，窄屏下溢出容器，故改为撑满可用宽度 */
        width: 100%;
        grid-template-columns: 1fr;
        gap: 2rem;
        padding: 1rem 0.85rem;
        border-radius: 1rem;
      }
      .stage__col--app {
        display: grid;
        grid-template-columns: repeat(3, minmax(0, 1fr));
        gap: 0.5rem;
      }
      .stage__label {
        /* 手机端恢复为文档流内的标题行 */
        position: static;
        left: auto;
        bottom: auto;
        grid-column: 1 / -1;
        margin-bottom: 0;
        text-align: center;
      }
      .app-card {
        padding: 0.55rem 0.3rem 0.45rem;
      }
      .app-card__name {
        font-size: 0.75rem;
      }
      .stage__col--targets {
        grid-template-columns: 1fr;
      }
      /* 窄屏下 MCPs 的四个图标排成一行，避免 2×2 时单元格过宽产生大片空白 */
      .target-card[data-link-node="mcps"] .target-card__grid--two {
        grid-template-columns: repeat(4, minmax(0, 1fr));
        grid-template-rows: 1fr;
      }
    }

    @media (prefers-reduced-motion: reduce) {
      html {
        scroll-behavior: auto;
      }
      *,
      *::before,
      *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
      }
    }

    /* ========== 返回顶部悬浮按钮（固定右下角，滚动 300px 后显示） ========== */
    .back-to-top {
      position: fixed;
      right: 20px;
      bottom: 120px; /* 距底部 120px，较默认位置整体上移 100px */
      z-index: 999;
      width: 48px;
      height: 48px;
      padding: 0;
      display: grid;
      place-items: center;
      border: 1px solid rgba(31, 36, 48, 0.12);
      border-radius: 8px;
      background-color: #ffffff;
      color: #1f2430; /* 箭头：深灰色 */
      box-shadow: 0 4px 14px rgba(16, 24, 40, 0.14);
      cursor: pointer;
      /* 默认隐藏：透明 + 下沉，避免占位闪烁 */
      opacity: 0;
      visibility: hidden;
      transform: translateY(8px);
      transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s ease,
        background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease,
        box-shadow 0.3s ease;
    }

    .back-to-top.is-visible {
      opacity: 1;
      visibility: visible;
      transform: translateY(0);
    }

    .back-to-top:hover {
      background-color: #0076ff;
      color: #ffffff; /* 箭头同步变白 */
      border-color: #0076ff;
      box-shadow: 0 6px 18px rgba(0, 118, 255, 0.32);
    }

    .back-to-top svg {
      width: 20px;
      height: 20px;
    }

    @media (max-width: 640px) {
      .back-to-top {
        right: 16px;
        bottom: 116px; /* 移动端同样上移 100px */
      }
    }