.page-about {
  --rail-w: 104px;
  --rail-gap: 32px;
}

/* ---------- 面包屑 ---------- */
.page-about .crumbs {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 22px 0 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--rock);
}

.page-about .crumbs a {
  color: var(--silver);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .2s ease, border-color .2s ease;
}

.page-about .crumbs a:hover {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .crumbs__sep {
  color: var(--rock);
}

/* ---------- 文档骨架：左编号立柱 + 右正文 ---------- */
.page-about .about-doc {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  margin-top: 6px;
}

.page-about .about-rail {
  display: none;
}

.page-about .about-main {
  min-width: 0;
}

.page-about .about-block {
  padding: 48px 0;
  border-top: 1px solid var(--line);
}

.page-about .about-block--first {
  border-top: 0;
  padding-top: 22px;
}

.page-about .about-block--first .about-head {
  padding-bottom: 4px;
}

.page-about .section-head.about-head {
  display: grid;
  gap: 10px;
  margin-bottom: 28px;
}

.page-about .section-head.about-head .section-num {
  font-family: var(--font-mono);
  font-size: clamp(44px, 9vw, 92px);
  font-weight: 700;
  line-height: .82;
  letter-spacing: -.02em;
  color: var(--clay);
  opacity: .92;
  display: block;
}

.page-about .about-head .eyebrow {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--cyan);
  text-transform: uppercase;
}

.page-about .about-head h1 {
  margin: 0;
  font-size: clamp(32px, 6.2vw, 62px);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -.015em;
  color: var(--paper);
  max-width: 20em;
}

.page-about .about-head h2 {
  margin: 0;
  font-size: clamp(27px, 4.6vw, 44px);
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: -.01em;
  color: var(--paper);
  max-width: 22em;
}

.page-about .about-head .lede {
  margin: 14px 0 0;
  max-width: 62ch;
  font-size: 17px;
  line-height: 1.75;
  color: var(--paper-dim);
}

/* ---------- 首屏数据区 ---------- */
.page-about .about-cover__grid {
  display: grid;
  gap: 26px;
  align-items: start;
}

.page-about .about-cover__body {
  min-width: 0;
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: var(--frame) solid var(--line-strong);
  box-shadow: var(--shadow-sm);
}

.page-about .about-stats .metric {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 18px 16px 20px;
  background: var(--ink);
  border-left: 3px solid transparent;
  transition: border-color .2s ease, background .2s ease;
}

.page-about .about-stats .metric:hover {
  background: var(--wine);
  border-left-color: var(--cyan);
}

.page-about .about-stats .metric__value {
  font-family: var(--font-mono);
  font-size: clamp(28px, 5vw, 40px);
  font-weight: 700;
  line-height: 1;
  color: var(--cyan);
  letter-spacing: -.02em;
}

.page-about .about-stats .metric__label {
  font-size: 13px;
  line-height: 1.5;
  color: var(--silver);
}

.page-about .about-cover__body .data-note {
  margin: 14px 0 0;
  padding-left: 12px;
  border-left: 2px solid var(--rock);
  font-size: 13px;
  line-height: 1.7;
  color: var(--rock);
}

.page-about .about-cover__actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px 22px;
  margin-top: 26px;
}

.page-about .about-cover__media {
  border: var(--frame) solid var(--line-strong);
  box-shadow: var(--shadow);
  background: var(--ink-2);
  margin: 0;
}

.page-about .about-cover__media img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  aspect-ratio: 7 / 5;
}

.page-about .media-frame__caption {
  display: block;
  padding: 10px 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--silver);
  background: var(--ink-2);
  border-top: 1px solid var(--line);
}

/* ---------- 阶段轴 ---------- */
.page-about .about-stage__media {
  margin: 0 0 26px;
  border: var(--frame) solid var(--line-strong);
  box-shadow: var(--shadow-sm);
}

.page-about .about-stage__media img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  aspect-ratio: 3 / 1;
}

.page-about .about-stage {
  margin-top: 0;
}

.page-about .stage-track {
  list-style: none;
  margin: 0;
  padding: 0 0 10px;
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(238px, 82%);
  gap: 12px;
  overflow-x: auto;
  scroll-snap-type: x proximity;
  -webkit-overflow-scrolling: touch;
}

.page-about .stage {
  scroll-snap-align: start;
  position: relative;
  padding: 22px 18px 24px;
  border: 1px solid var(--line-strong);
  border-left: 5px solid var(--clay);
  background: linear-gradient(160deg, rgba(94, 27, 36, .55) 0%, rgba(20, 16, 15, .96) 78%);
  box-shadow: var(--shadow-sm);
  transition: transform .22s ease, border-color .22s ease, box-shadow .22s ease;
}

.page-about .stage:hover,
.page-about .stage:focus-within {
  transform: translateX(-2px);
  border-color: var(--cyan);
  border-left-color: var(--cyan);
  box-shadow: var(--shadow);
}

.page-about .stage__idx {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--brass);
  margin-bottom: 10px;
}

.page-about .stage__title {
  margin: 0 0 10px;
  font-size: 22px;
  font-weight: 800;
  line-height: 1.25;
  color: var(--paper);
}

.page-about .stage__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--paper-dim);
}

.page-about .stage__more {
  margin: 0;
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.65;
  color: var(--cyan);
  transition: max-height .28s ease, opacity .28s ease, margin-top .28s ease;
}

.page-about .stage:hover .stage__more,
.page-about .stage:focus-within .stage__more {
  max-height: 90px;
  opacity: 1;
  margin-top: 12px;
}

/* ---------- 两套数据对照 ---------- */
.page-about .dual-grid {
  display: grid;
  gap: 18px;
}

.page-about .dual-card {
  padding: 24px 20px 26px;
  border: var(--frame) solid var(--line-strong);
  box-shadow: var(--shadow-sm);
}

.page-about .dual-card .eyebrow {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--brass);
}

.page-about .dual-card h3 {
  margin: 0 0 12px;
  font-size: clamp(21px, 3.4vw, 27px);
  font-weight: 800;
  line-height: 1.3;
  color: var(--paper);
}

.page-about .dual-card p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--paper-dim);
}

.page-about .dual-card--signal {
  background: var(--ink);
}

.page-about .dual-card--signal h3 {
  color: var(--cyan);
}

.page-about .dual-list {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .dual-list li {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 12px;
  justify-content: space-between;
  padding: 10px 0;
  border-bottom: 1px solid var(--line);
  font-size: 13.5px;
}

.page-about .dual-list__k {
  color: var(--silver);
}

.page-about .dual-list__v {
  color: var(--paper);
  font-weight: 600;
}

.page-about .dual-list__v.mono {
  font-family: var(--font-mono);
  color: var(--cyan);
  letter-spacing: .01em;
}

.page-about .about-note {
  margin-top: 22px;
  padding: 18px 20px;
  border: 1px solid var(--line);
  border-left: 5px solid var(--clay);
  background: rgba(94, 27, 36, .22);
  font-size: 15px;
  line-height: 1.8;
  color: var(--paper-dim);
}

.page-about .about-note p {
  margin: 0;
}

/* ---------- 服务节点 ---------- */
.page-about .node-layout {
  display: grid;
  gap: 20px;
}

.page-about .node-layout__media {
  margin: 0;
  border: var(--frame) solid var(--line-strong);
  box-shadow: var(--shadow-sm);
  align-self: start;
}

.page-about .node-layout__media img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  aspect-ratio: 4 / 3;
}

.page-about .node-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: var(--frame) solid var(--line-strong);
}

.page-about .node-card {
  display: flex;
  flex-direction: column;
  gap: 7px;
  padding: 20px 18px 22px;
  background: var(--ink);
  border-top: 3px solid transparent;
  text-decoration: none;
  color: var(--paper);
  transition: background .2s ease, box-shadow .2s ease, border-color .2s ease;
}

.page-about .node-card:hover,
.page-about .node-card:focus-visible {
  background: var(--wine);
  border-top-color: var(--cyan);
  box-shadow: inset 0 0 0 3px var(--cyan);
  outline: none;
}

.page-about .node-card__city {
  font-size: 21px;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: .02em;
}

.page-about .node-card__role {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .05em;
  color: var(--moss-light);
}

.page-about .node-card__desc {
  font-size: 14px;
  line-height: 1.7;
  color: var(--paper-dim);
}

.page-about .node-card__go {
  margin-top: 6px;
  font-size: 13px;
  color: var(--cyan);
  transition: transform .2s ease;
}

.page-about .node-card:hover .node-card__go {
  transform: translateX(2px);
}

/* ---------- 备案与承诺 ---------- */
.page-about .trust-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: var(--frame) solid var(--line-strong);
}

.page-about .trust-item {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 14px;
  padding: 16px 18px;
  background: var(--ink);
  transition: background .2s ease;
}

.page-about .trust-item:hover {
  background: var(--ink-2);
}

.page-about .trust-item__text {
  flex: 1 1 240px;
  min-width: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--paper-dim);
}

.page-about .about-cta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px 24px;
  margin-top: 28px;
  padding: 22px 20px;
  border: var(--frame) solid var(--wine-hi);
  background: var(--wine-hi);
  box-shadow: var(--shadow);
}

.page-about .about-cta__text {
  flex: 1 1 260px;
  margin: 0;
  font-size: 15.5px;
  line-height: 1.7;
  color: var(--paper);
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-block {
    padding: 60px 0;
  }

  .page-about .node-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-cover__grid {
    grid-template-columns: 7fr 5fr;
    gap: 36px;
  }

  .page-about .dual-grid {
    grid-template-columns: 7fr 5fr;
    gap: 24px;
  }

  .page-about .about-stage__media {
    margin-bottom: 30px;
  }

  .page-about .stage-track {
    grid-auto-flow: row;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    grid-auto-columns: auto;
    overflow-x: visible;
    padding-bottom: 0;
    gap: 14px;
  }

  .page-about .stage__more {
    max-height: 90px;
    opacity: .72;
    margin-top: 12px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-doc {
    grid-template-columns: var(--rail-w) 1fr;
    column-gap: var(--rail-gap);
  }

  .page-about .about-rail {
    display: block;
    align-self: start;
    position: sticky;
    top: 148px;
    padding-top: 34px;
  }

  .page-about .about-rail__list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: grid;
    gap: 20px;
  }

  .page-about .about-rail__item {
    display: grid;
    gap: 3px;
    padding-left: 12px;
    border-left: 2px solid var(--line);
    transition: border-color .2s ease;
  }

  .page-about .about-rail__item:hover {
    border-left-color: var(--cyan);
  }

  .page-about .about-rail__num {
    font-family: var(--font-mono);
    font-size: 16px;
    font-weight: 700;
    color: var(--clay);
    letter-spacing: .02em;
  }

  .page-about .about-rail__label {
    font-size: 12.5px;
    line-height: 1.4;
    color: var(--rock);
    letter-spacing: .04em;
  }

  .page-about .about-block {
    padding: 76px 0;
  }

  /* 阶段轴横跨整个版心，打破双栏节奏 */
  .page-about .about-stage {
    margin-left: calc(-1 * (var(--rail-w) + var(--rail-gap)));
  }

  .page-about .about-stage__media {
    margin-left: calc(-1 * (var(--rail-w) + var(--rail-gap)));
  }

  .page-about .node-layout {
    grid-template-columns: 5fr 7fr;
    gap: 26px;
  }

  .page-about .node-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1280px) {
  .page-about .stage {
    padding: 26px 22px 28px;
  }

  .page-about .node-card {
    padding: 24px 22px 26px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .stage,
  .page-about .stage__more,
  .page-about .node-card,
  .page-about .node-card__go,
  .page-about .about-stats .metric,
  .page-about .crumbs a {
    transition: color .2s ease, background-color .2s ease, border-color .2s ease;
  }

  .page-about .stage:hover,
  .page-about .stage:focus-within,
  .page-about .node-card:hover .node-card__go {
    transform: none;
  }
}
<<<END>>>