.page-about {
  --ab-rail-w: 186px;
  --ab-gap: clamp(18px, 3vw, 34px);
  --ab-pad: clamp(16px, 2.4vw, 26px);
  display: block;
  background: var(--void);
  padding-bottom: clamp(40px, 7vw, 88px);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  padding: clamp(24px, 5vw, 56px) 0 clamp(22px, 4vw, 42px);
  border-bottom: var(--hair);
}
.page-about .ab-hero__kicker {
  margin: 0 0 14px;
}
.page-about .ab-hero__title {
  margin: 0 0 clamp(18px, 3vw, 30px);
  max-width: 20ch;
}
.page-about .ab-hero__body {
  display: grid;
  gap: var(--ab-gap);
  grid-template-columns: 1fr;
}
.page-about .ab-hero__body .pg-lead {
  max-width: 52ch;
  margin: 0;
}
.page-about .ab-hero__stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: var(--hair-soft);
}
.page-about .ab-stat {
  background: var(--deck);
  padding: 12px 14px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.page-about .ab-stat__num {
  font-size: 22px;
  color: var(--gold);
  line-height: 1.1;
}
.page-about .ab-stat__key {
  font-size: 12px;
  color: var(--muted);
  letter-spacing: .04em;
}

/* ---------- 主体网格与刻度栏 ---------- */
.page-about .ab-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--ab-gap);
  padding-top: clamp(22px, 3.4vw, 40px);
}
.page-about .ab-rail {
  border-top: var(--hair);
  border-bottom: var(--hair);
  padding: 12px 0;
}
.page-about .ab-rail__title {
  margin: 0 0 8px;
  font-size: 12px;
  letter-spacing: .28em;
  color: var(--muted);
}
.page-about .ab-rail__title + .ab-rail__list + .ab-rail__title {
  margin-top: 14px;
}
.page-about .ab-rail__list {
  list-style: none;
  margin: 0;
  padding: 0 0 2px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: none;
}
.page-about .ab-rail__list::-webkit-scrollbar {
  display: none;
}
.page-about .ab-rail__link {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  padding: 7px 10px;
  border: var(--hair-soft);
  background: var(--deck);
  text-decoration: none;
  white-space: nowrap;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease), color var(--dur) var(--ease);
}
.page-about .ab-rail__num {
  font-size: 12px;
  color: var(--pulse);
}
.page-about .ab-rail__label {
  font-size: 12px;
  color: var(--text);
}
.page-about .ab-rail__link:hover,
.page-about .ab-rail__link:focus-visible {
  border-color: var(--volt);
  background: var(--rail);
}
.page-about .ab-rail__link--now .ab-rail__num {
  color: var(--cyan);
}

/* ---------- 区块骨架 ---------- */
.page-about .ab-section {
  padding: 0 0 clamp(26px, 4vw, 48px);
  margin: 0 0 clamp(26px, 4vw, 48px);
  border-bottom: var(--hair-soft);
}
.page-about .ab-section:last-child {
  border-bottom: 0;
  margin-bottom: 0;
  padding-bottom: 0;
}
.page-about .ab-section__head {
  margin-bottom: clamp(16px, 2.6vw, 26px);
}
.page-about .ab-section__head .pg-h2 {
  margin: 10px 0 0;
}
.page-about .ab-section__head .pg-body {
  margin: 12px 0 0;
  max-width: 60ch;
}
.page-about .ab-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--ab-gap);
}

/* ---------- 字段层级 ---------- */
.page-about .ab-layers {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}
.page-about .ab-layer {
  position: relative;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 12px;
  padding: 14px 16px 14px 20px;
  background: var(--deck);
  border: var(--hair-soft);
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.page-about .ab-layer::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
}
.page-about .ab-layer--locate::before { background: var(--volt); }
.page-about .ab-layer--stat::before { background: var(--cyan); }
.page-about .ab-layer--mark::before { background: var(--gold); }
.page-about .ab-layer:hover {
  border-color: var(--line);
  background: var(--rail);
}
.page-about .ab-layer__tag {
  font-size: 13px;
  color: var(--muted);
  padding-top: 3px;
}
.page-about .ab-layer__text .pg-h3 {
  margin: 0 0 6px;
}
.page-about .ab-layer__text .pg-body {
  margin: 0;
  font-size: 14px;
}

.page-about .ab-figure {
  margin: 0;
}
.page-about .ab-figure .pg-figure__frame {
  --ar: 900 / 600;
  border: var(--hair-soft);
  background: var(--deck);
  overflow: hidden;
}
.page-about .ab-figure--tall .pg-figure__frame {
  --ar: 1000 / 1200;
}
.page-about .ab-figure img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.page-about .ab-figure .pg-figure__cap {
  margin-top: 10px;
  font-size: 12px;
  color: var(--muted);
  line-height: 1.7;
}

/* ---------- 流程数据带 ---------- */
.page-about .ab-band {
  position: relative;
  overflow: hidden;
  border: var(--hair-soft);
  margin-bottom: clamp(16px, 2.6vw, 26px);
  isolation: isolate;
}
.page-about .ab-band__img {
  display: block;
  width: 100%;
  height: auto;
  max-height: 240px;
  object-fit: cover;
  opacity: .55;
}
.page-about .ab-band__text {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  gap: 8px;
  padding: clamp(16px, 3vw, 32px);
  background: linear-gradient(180deg, rgba(5, 10, 26, .25) 0%, rgba(5, 10, 26, .93) 78%);
}
.page-about .ab-band__text .pg-h2 {
  margin: 0;
}
.page-about .ab-band__lead {
  margin: 4px 0 0;
  max-width: 58ch;
  font-size: 14px;
}

.page-about .ab-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  border: var(--hair-soft);
  background: var(--line);
  display: grid;
  gap: 1px;
}
.page-about .ab-step {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 14px;
  padding: var(--ab-pad) calc(var(--ab-pad) - 4px);
  background: var(--deck);
  outline: none;
  transition: background var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}
.page-about .ab-step:hover,
.page-about .ab-step:focus-visible {
  background: var(--rail);
  box-shadow: inset 3px 0 0 0 var(--volt);
}
.page-about .ab-step__idx {
  font-size: 15px;
  color: var(--gold);
  letter-spacing: .16em;
  padding-top: 2px;
}
.page-about .ab-step__body .pg-h3 {
  margin: 0 0 6px;
}
.page-about .ab-step__body .pg-body {
  margin: 0;
  font-size: 14px;
  max-width: 58ch;
}
.page-about .ab-step__io {
  margin: 10px 0 0;
  display: grid;
  gap: 5px;
}
.page-about .ab-step__row {
  display: grid;
  grid-template-columns: 46px 1fr;
  gap: 10px;
  align-items: baseline;
}
.page-about .ab-step__row dt {
  font-size: 12px;
  color: var(--muted);
  letter-spacing: .12em;
}
.page-about .ab-step__row dd {
  margin: 0;
  font-family: var(--mono);
  font-size: 12.5px;
  letter-spacing: .06em;
  color: var(--pulse);
}

/* ---------- 职能分工 ---------- */
.page-about .ab-team {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}
.page-about .ab-team__card {
  background: var(--deck);
  border: var(--hair-soft);
  padding: var(--ab-pad);
  display: flex;
  flex-direction: column;
  gap: 8px;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}
.page-about .ab-team__card:hover {
  border-color: var(--volt);
  background: var(--rail);
}
.page-about .ab-team__num {
  font-size: 26px;
  color: var(--cyan);
  line-height: 1;
}
.page-about .ab-team__card .pg-h3 {
  margin: 0;
}
.page-about .ab-team__card .pg-body {
  margin: 0;
  font-size: 14px;
}
.page-about .ab-team__scope {
  margin: auto 0 0;
  padding-top: 10px;
  border-top: var(--hair-soft);
  font-size: 12px;
  color: var(--muted);
}

/* ---------- 版本刻度 ---------- */
.page-about .ab-timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 20px;
  border-left: var(--hair-soft);
}
.page-about .ab-ver {
  position: relative;
  padding: 0 0 20px;
}
.page-about .ab-ver:last-child {
  padding-bottom: 0;
}
.page-about .ab-ver::before {
  content: "";
  position: absolute;
  left: -25px;
  top: 7px;
  width: 9px;
  height: 9px;
  background: var(--deck);
  border: 1px solid var(--line);
}
.page-about .ab-ver--current::before {
  background: var(--cyan);
  border-color: var(--cyan);
}
.page-about .ab-ver:target::before {
  background: var(--gold);
  border-color: var(--gold);
}
.page-about .ab-ver__year {
  margin: 0 0 4px;
  font-size: 13px;
  letter-spacing: .2em;
  color: var(--pulse);
}
.page-about .ab-ver--current .ab-ver__year {
  color: var(--cyan);
}
.page-about .ab-ver .pg-h3 {
  margin: 0 0 6px;
}
.page-about .ab-ver .pg-body {
  margin: 0;
  font-size: 14px;
  max-width: 56ch;
}

/* ---------- 差异更正 ---------- */
.page-about .ab-list {
  list-style: none;
  margin: 16px 0;
  padding: 0;
  border-top: var(--hair-soft);
}
.page-about .ab-list__item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 12px;
  padding: 10px 2px;
  border-bottom: var(--hair-soft);
  font-size: 14px;
  color: var(--text);
}
.page-about .ab-list__no {
  font-size: 12px;
  color: var(--gold);
  padding-top: 3px;
}
.page-about .ab-contact {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  padding: 12px 14px;
  border: var(--hair-soft);
  background: var(--deck);
  margin-top: 6px;
}
.page-about .ab-contact__key {
  font-size: 12px;
  color: var(--muted);
  letter-spacing: .12em;
}
.page-about .ab-contact__val {
  font-size: 14px;
  color: var(--gold);
  word-break: break-all;
}
.page-about .ab-contact__btn {
  margin-left: auto;
}
.page-about .ab-feedback__main .pg-note {
  margin-top: 14px;
  font-size: 12px;
  line-height: 1.9;
}
.page-about .ab-feedback__main .pg-note a {
  color: var(--pulse);
  text-decoration: none;
  border-bottom: 1px solid rgba(167, 139, 255, .45);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.page-about .ab-feedback__main .pg-note a:hover,
.page-about .ab-feedback__main .pg-note a:focus-visible {
  color: var(--cyan);
  border-color: var(--cyan);
}

.page-about .ab-boundaries {
  border: var(--hair-soft);
  background: var(--deck);
  padding: 0 var(--ab-pad) 6px;
}
.page-about .ab-boundaries__title {
  margin: 0;
  padding: 16px 0 12px;
  border-bottom: var(--hair);
}
.page-about .ab-fold {
  border-bottom: var(--hair-soft);
}
.page-about .ab-fold:last-child {
  border-bottom: 0;
}
.page-about .ab-fold__sum {
  cursor: pointer;
  padding: 12px 0;
  font-size: 14px;
  color: var(--text);
  list-style: none;
  display: flex;
  align-items: center;
  gap: 10px;
  transition: color var(--dur) var(--ease);
}
.page-about .ab-fold__sum::-webkit-details-marker {
  display: none;
}
.page-about .ab-fold__sum::before {
  content: "+";
  font-family: var(--mono);
  font-size: 14px;
  color: var(--volt);
  width: 14px;
  flex: 0 0 14px;
  transition: transform var(--dur) var(--ease), color var(--dur) var(--ease);
}
.page-about .ab-fold[open] .ab-fold__sum::before {
  content: "–";
  color: var(--cyan);
}
.page-about .ab-fold__sum:hover,
.page-about .ab-fold__sum:focus-visible {
  color: var(--pulse);
}
.page-about .ab-fold .pg-body {
  margin: 0 0 14px 24px;
  font-size: 13.5px;
  color: var(--muted);
}

/* ---------- 桌面布局 ---------- */
@media (min-width: 720px) {
  .page-about .ab-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .ab-hero__body {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
    align-items: end;
  }
  .page-about .ab-team {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .ab-band__img {
    max-height: 320px;
  }
}

@media (min-width: 980px) {
  .page-about .ab-layout {
    grid-template-columns: var(--ab-rail-w) minmax(0, 1fr);
    gap: clamp(24px, 4vw, 52px);
  }
  .page-about .ab-rail {
    position: sticky;
    top: 96px;
    align-self: start;
    max-height: calc(100vh - 130px);
    overflow-y: auto;
    border-bottom: 0;
    padding-bottom: 0;
  }
  .page-about .ab-rail__list {
    flex-direction: column;
    overflow: visible;
    gap: 0;
  }
  .page-about .ab-rail__link {
    width: 100%;
    justify-content: flex-start;
    border: 0;
    border-left: 2px solid transparent;
    background: transparent;
    padding: 6px 8px;
    white-space: normal;
  }
  .page-about .ab-rail__link:hover,
  .page-about .ab-rail__link:focus-visible {
    border-left-color: var(--volt);
    background: var(--deck);
  }
  .page-about .ab-rail__link--now {
    border-left-color: var(--cyan);
  }
  .page-about .ab-split--fig {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
    align-items: start;
  }
  .page-about .ab-split--fig-rev {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    align-items: start;
    gap: clamp(28px, 4vw, 56px);
  }
  .page-about .ab-figure--tall {
    position: sticky;
    top: 108px;
  }
  .page-about .ab-layer--stat {
    margin-left: 18px;
  }
  .page-about .ab-layer--mark {
    margin-left: 36px;
  }
  .page-about .ab-step__io {
    max-height: 0;
    opacity: 0;
    margin-top: 0;
    overflow: hidden;
    transition: max-height 200ms var(--ease), opacity 160ms var(--ease), margin-top var(--dur) var(--ease);
  }
  .page-about .ab-step:hover .ab-step__io,
  .page-about .ab-step:focus-within .ab-step__io,
  .page-about .ab-step:focus-visible .ab-step__io {
    max-height: 150px;
    opacity: 1;
    margin-top: 10px;
  }
  .page-about .ab-feedback__main {
    padding-right: clamp(16px, 3vw, 34px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition: none !important;
  }
  .page-about .ab-step__io {
    max-height: none;
    opacity: 1;
    margin-top: 10px;
    overflow: visible;
  }
}
<<<END>>>