.page-about {
  --ab-shadow: 4px 4px 0 rgba(5, 16, 31, .6);
  --ab-shadow-soft: 3px 3px 0 rgba(5, 16, 31, .45);
  --ab-track: rgba(34, 211, 238, .35);
  overflow-x: hidden;
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  list-style: none;
  margin: 0 0 1.25rem;
  padding: 0;
  font-size: .8125rem;
  letter-spacing: .04em;
}
.page-about .breadcrumb li + li::before {
  content: "/";
  margin-right: .5rem;
  color: var(--steel);
}
.page-about .breadcrumb a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}
.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  border-bottom-color: var(--cyan);
}
.page-about .breadcrumb [aria-current="page"] {
  color: var(--steel);
}

/* ---------- 章节序号竖排注释 ---------- */
.page-about .annotation[class*="__seq"] {
  display: block;
  font-family: var(--font-mono);
  font-size: .75rem;
  letter-spacing: .3em;
  color: var(--lime);
  margin-bottom: .75rem;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  padding-top: 1.5rem;
  padding-bottom: 3.5rem;
}
.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: -10% -40% auto auto;
  width: 62%;
  height: 78%;
  background: linear-gradient(150deg, rgba(34, 211, 238, .22), rgba(199, 245, 59, .1) 62%, transparent 78%);
  clip-path: polygon(18% 0, 100% 0, 78% 100%, 0 84%);
  pointer-events: none;
}
.page-about .ab-hero__grid {
  position: relative;
  display: grid;
  gap: 2.5rem;
}
.page-about .ab-hero__tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: .75rem;
  letter-spacing: .28em;
  color: var(--cyan);
  border-left: 2px solid var(--lime);
  padding-left: .6rem;
  margin-bottom: 1rem;
}
.page-about .ab-hero__title {
  margin: 0 0 1.25rem;
  color: var(--paper);
  line-height: 1.02;
}
.page-about .ab-hero__lede {
  max-width: 40rem;
  color: var(--text-soft);
  margin: 0 0 1.75rem;
}
.page-about .ab-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
}
.page-about .ab-hero__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--ab-track);
  border: 1px solid var(--ab-track);
  box-shadow: var(--ab-shadow);
}
.page-about .ab-hero__stat {
  background: var(--night-2);
  padding: 1.1rem 1rem 1.25rem;
  display: flex;
  flex-direction: column;
  gap: .2rem;
}
.page-about .ab-hero__stat--lime {
  background: var(--night);
  border-top: 2px solid var(--lime);
}
.page-about .ab-hero__stat-num {
  font-size: 2.5rem;
  line-height: 1;
  color: var(--cyan);
}
.page-about .ab-hero__stat--lime .ab-hero__stat-num {
  color: var(--lime);
}
.page-about .ab-hero__stat .stat__unit {
  font-family: var(--font-mono);
  font-size: .8125rem;
  color: var(--steel);
  letter-spacing: .04em;
}
.page-about .ab-hero__stat .stat__label {
  font-size: .8125rem;
  color: var(--text-soft);
}

/* ---------- 站点起点 ---------- */
.page-about .ab-origin__grid {
  display: grid;
  gap: 2.25rem;
  align-items: start;
}
.page-about .ab-origin__text h2 {
  margin: .35rem 0 1.25rem;
  color: var(--paper);
}
.page-about .ab-origin__text .prose p {
  color: var(--text-soft);
}
.page-about .ab-origin__facts {
  list-style: none;
  margin: 1.75rem 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}
.page-about .ab-origin__facts li {
  display: flex;
  align-items: baseline;
  gap: .75rem;
  padding: .85rem 0;
  border-bottom: 1px solid var(--line);
  font-size: .9375rem;
  color: var(--text-soft);
}
.page-about .ab-origin__facts .num {
  flex: 0 0 auto;
  font-size: 1.5rem;
  color: var(--lime);
  min-width: 2.5rem;
}
.page-about .ab-origin__figure {
  margin: 0;
}

/* ---------- 档案构成 ---------- */
.page-about .ab-structure__head {
  max-width: 46rem;
}
.page-about .ab-structure__head h2 {
  margin: .35rem 0 1rem;
  color: var(--paper);
}
.page-about .ab-layers {
  list-style: none;
  margin: 2.25rem 0 0;
  padding: 0;
  display: grid;
  gap: 1rem;
  counter-reset: none;
}
.page-about .ab-layer {
  position: relative;
  padding: 1.25rem 1.25rem 1.4rem;
  border-left: 3px solid var(--cyan);
}
.page-about .ab-layer--none {}
.page-about .ab-layer__idx {
  display: block;
  font-size: .75rem;
  letter-spacing: .22em;
  color: var(--steel);
  margin-bottom: .5rem;
}
.page-about .ab-layer .card__title {
  color: var(--paper);
  margin: 0 0 .5rem;
  font-size: 1.25rem;
}
.page-about .ab-layer p {
  margin: 0;
  font-size: .9375rem;
  color: var(--text-soft);
}
.page-about .ab-layer.card--accent {
  border-left-color: var(--lime);
}
.page-about .ab-layer.card--accent .card__title {
  color: var(--ink);
}
.page-about .ab-layer.card--accent p {
  color: rgba(5, 16, 31, .78);
}
.page-about .ab-layer.card--accent .ab-layer__idx {
  color: rgba(5, 16, 31, .6);
}
.page-about .ab-structure__note {
  margin-top: 2rem;
  padding: 1.25rem 1.4rem;
  background: var(--night-2);
  border: 1px solid var(--line);
  box-shadow: var(--ab-shadow-soft);
  display: flex;
  flex-direction: column;
  gap: 1rem;
  align-items: flex-start;
}
.page-about .ab-structure__note p {
  margin: 0;
  color: var(--text-soft);
  font-size: .9375rem;
}

/* ---------- 号码与简史 ---------- */
.page-about .ab-numbers__grid {
  display: grid;
  gap: 2.25rem;
  align-items: center;
}
.page-about .ab-numbers__intro h2 {
  margin: .35rem 0 1.25rem;
  color: var(--paper);
}
.page-about .ab-numbers__intro .prose p {
  color: var(--text-soft);
}
.page-about .ab-numbers__figure {
  margin: 0;
}
.page-about .ab-numgrid {
  margin-top: 2.5rem;
}
.page-about .ab-numgrid__title {
  font-size: 1.0625rem;
  color: var(--cyan);
  letter-spacing: .04em;
  margin: 0 0 1rem;
  padding-bottom: .75rem;
  border-bottom: 1px solid var(--line);
}
.page-about .ab-numgrid__groups {
  display: grid;
  gap: .75rem;
}
.page-about .ab-numgroup {
  border: 1px solid var(--line);
  background: var(--night-2);
  box-shadow: var(--ab-shadow-soft);
}
.page-about .ab-numgroup > summary {
  cursor: pointer;
  padding: 1rem 1.1rem;
  font-weight: 600;
  color: var(--paper);
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.page-about .ab-numgroup > summary::-webkit-details-marker {
  display: none;
}
.page-about .ab-numgroup > summary::after {
  content: "+";
  font-family: var(--font-mono);
  color: var(--lime);
  font-size: 1.25rem;
  line-height: 1;
}
.page-about .ab-numgroup[open] > summary::after {
  content: "–";
}
.page-about .ab-numgroup .qa__body {
  padding: 0 1.1rem 1.1rem;
}
.page-about .ab-numlist {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: .5rem;
}
.page-about .ab-numlist li {
  display: flex;
  gap: .85rem;
  align-items: baseline;
  padding: .5rem 0;
  border-bottom: 1px dashed var(--line);
  font-size: .875rem;
  color: var(--text-soft);
}
.page-about .ab-numlist li:last-child {
  border-bottom: 0;
}
.page-about .ab-numlist__no {
  flex: 0 0 auto;
  color: var(--cyan);
  font-size: 1rem;
  letter-spacing: .08em;
}

/* ---------- 团队 ---------- */
.page-about .ab-team__head {
  max-width: 46rem;
}
.page-about .ab-team__head h2 {
  margin: .35rem 0 1rem;
  color: var(--ink);
}
.page-about .ab-team__head .lede {
  color: rgba(5, 16, 31, .74);
}
.page-about .ab-team__grid {
  margin-top: 2.25rem;
  display: grid;
  gap: 1rem;
}
.page-about .ab-team__card {
  background: #fff;
  color: var(--ink);
  border: 1px solid rgba(5, 16, 31, .16);
  box-shadow: var(--ab-shadow);
  padding: 1.25rem 1.25rem 1.35rem;
  display: flex;
  flex-direction: column;
  gap: .55rem;
}
.page-about .ab-team__card h3 {
  margin: 0;
  font-size: 1.1875rem;
}
.page-about .ab-team__card p {
  margin: 0;
  font-size: .9375rem;
  color: rgba(5, 16, 31, .76);
  flex: 1 1 auto;
}
.page-about .ab-team__card .card__label {
  font-family: var(--font-mono);
  font-size: .75rem;
  letter-spacing: .18em;
  color: var(--grass);
}
.page-about .ab-team__time {
  display: inline-block;
  align-self: flex-start;
  margin-top: .25rem;
  padding: .2rem .5rem;
  font-size: .75rem;
  background: var(--night);
  color: var(--lime);
}
.page-about .ab-team__card.card--accent {
  background: var(--lime);
  border-color: rgba(5, 16, 31, .3);
}
.page-about .ab-team__card.card--accent .card__label {
  color: rgba(5, 16, 31, .7);
}
.page-about .ab-team__card.card--accent .ab-team__time {
  background: var(--ink);
  color: var(--lime);
}
.page-about .ab-team__foot {
  margin: 2rem 0 0;
  padding-top: 1.25rem;
  border-top: 1px solid rgba(5, 16, 31, .16);
  font-size: .9375rem;
  color: rgba(5, 16, 31, .8);
  max-width: 52rem;
}
.page-about .ab-team__foot a {
  color: #14556b;
  font-weight: 600;
  margin-left: .35rem;
  border-bottom: 2px solid var(--cyan);
  text-decoration: none;
}
.page-about .ab-team__foot a:hover,
.page-about .ab-team__foot a:focus-visible {
  color: var(--ink);
}

/* ---------- 时间线 ---------- */
.page-about .ab-timeline__head {
  max-width: 48rem;
}
.page-about .ab-timeline__head h2 {
  margin: .35rem 0 1rem;
  color: var(--paper);
}
.page-about .ab-timeline__figure {
  margin: 2rem 0 2.5rem;
  border: 1px solid var(--cyan-line);
  box-shadow: var(--ab-shadow);
}
.page-about .ab-timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: .875rem;
  position: relative;
}
.page-about .ab-tl__item {
  position: relative;
  background: var(--night-2);
  border: 1px solid var(--line);
  box-shadow: var(--ab-shadow-soft);
}
.page-about .ab-tl__item > summary {
  cursor: pointer;
  list-style: none;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: .85rem;
  padding: 1rem 1.1rem;
}
.page-about .ab-tl__item > summary::-webkit-details-marker {
  display: none;
}
.page-about .ab-tl__year {
  font-size: 1.25rem;
  color: var(--lime);
  letter-spacing: .04em;
}
.page-about .ab-tl__title {
  font-weight: 600;
  color: var(--paper);
  font-size: .9375rem;
}
.page-about .ab-tl__dot {
  width: 10px;
  height: 10px;
  background: var(--cyan);
  box-shadow: 0 0 0 4px rgba(34, 211, 238, .18);
  flex: 0 0 auto;
}
.page-about .ab-tl__item[open] .ab-tl__dot {
  background: var(--lime);
  box-shadow: 0 0 0 4px rgba(199, 245, 59, .2);
}
.page-about .ab-tl__item .qa__body {
  padding: 0 1.1rem 1.15rem;
}
.page-about .ab-tl__item .qa__body p {
  margin: 0 0 .6rem;
  font-size: .9375rem;
  color: var(--text-soft);
}
.page-about .ab-tl__data {
  margin: 0;
  font-size: .8125rem;
  letter-spacing: .06em;
  color: var(--cyan);
  padding-top: .6rem;
  border-top: 1px dashed var(--line);
}
.page-about .ab-tl--now .ab-tl__item {
  border-color: var(--cyan-line);
  box-shadow: var(--ab-shadow);
}

/* ---------- 合作 ---------- */
.page-about .ab-coop__grid {
  display: grid;
  gap: 2.25rem;
  align-items: start;
}
.page-about .ab-coop__text h2 {
  margin: .35rem 0 1.25rem;
  color: var(--paper);
}
.page-about .ab-coop__text .prose p {
  color: var(--text-soft);
}
.page-about .ab-coop__actions {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
  margin-top: 1.75rem;
}
.page-about .ab-coop__links {
  border: 1px solid var(--line);
  background: var(--night-2);
  box-shadow: var(--ab-shadow);
  padding: 1.25rem 1.25rem 1.35rem;
}
.page-about .ab-coop__links-title {
  margin: 0 0 1rem;
  font-size: 1rem;
  color: var(--cyan);
  letter-spacing: .05em;
}
.page-about .ab-coop__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: .5rem;
}
.page-about .ab-coop__list a {
  display: flex;
  flex-direction: column;
  gap: .15rem;
  padding: .7rem .8rem;
  text-decoration: none;
  border-left: 3px solid var(--line-strong);
  transition: border-color .2s var(--ease), background-color .2s var(--ease);
}
.page-about .ab-coop__list a:hover,
.page-about .ab-coop__list a:focus-visible {
  border-left-color: var(--lime);
  background: rgba(34, 211, 238, .08);
}
.page-about .ab-coop__list-label {
  color: var(--paper);
  font-weight: 600;
  font-size: .9375rem;
}
.page-about .ab-coop__list-desc {
  color: var(--steel);
  font-size: .8125rem;
}

/* ---------- 图片自适应 ---------- */
.page-about .media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}
.page-about .media--4x5 img {
  aspect-ratio: 4 / 5;
}
.page-about .media--1x1 img {
  aspect-ratio: 1 / 1;
}
.page-about .media--3x2 img {
  aspect-ratio: 3 / 2;
}
.page-about .media__caption {
  display: block;
  margin-top: .6rem;
  font-size: .8125rem;
  color: var(--steel);
  letter-spacing: .02em;
}
.page-about .section--paper .media__caption {
  color: rgba(5, 16, 31, .62);
}

/* ---------- 响应式：≥720px ---------- */
@media (min-width: 720px) {
  .page-about .ab-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .ab-hero__stat-num {
    font-size: 3rem;
  }
  .page-about .ab-layers {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .ab-numgrid__groups {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .ab-team__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .ab-team__grid > :nth-child(2) {
    transform: translateY(18px);
  }
  .page-about .ab-team__grid > :nth-child(4) {
    transform: translateY(18px);
  }
}

/* ---------- 响应式：≥1024px ---------- */
@media (min-width: 1024px) {
  .page-about .ab-hero {
    padding-bottom: 5rem;
  }
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 3rem;
    align-items: end;
  }
  .page-about .ab-hero__stats {
    align-self: end;
  }
  .page-about .ab-origin__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 3.5rem;
  }
  .page-about .ab-numbers__grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    gap: 3.5rem;
  }
  .page-about .ab-layers {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: .875rem;
    align-items: stretch;
  }
  .page-about .ab-layer:nth-child(even) {
    transform: translateY(22px);
  }
  .page-about .ab-layer.card--accent {
    transform: translateY(-10px);
  }
  .page-about .ab-numgrid__groups {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .ab-team__grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 1.25rem;
  }
  .page-about .ab-team__grid > :nth-child(2) {
    transform: translateY(26px);
  }
  .page-about .ab-team__grid > :nth-child(4) {
    transform: translateY(26px);
  }
  .page-about .ab-timeline {
    grid-template-columns: repeat(6, minmax(0, 1fr));
    gap: 0;
    align-items: start;
    padding-top: 1.5rem;
    border-top: 1px solid var(--ab-track);
  }
  .page-about .ab-timeline::before {
    content: "";
    position: absolute;
    left: 0;
    right: 0;
    top: 1.5rem;
    height: 1px;
    background: linear-gradient(90deg, rgba(34, 211, 238, .12), var(--cyan), var(--lime));
    pointer-events: none;
  }
  .page-about .ab-tl {
    position: relative;
    background: transparent;
  }
  .page-about .ab-tl__item {
    background: transparent;
    border: 0;
    box-shadow: none;
    border-left: 1px solid var(--line);
    min-height: 100%;
  }
  .page-about .ab-tl__item > summary {
    grid-template-columns: 1fr;
    gap: .5rem;
    padding: 1.1rem 1rem .9rem;
  }
  .page-about .ab-tl__dot {
    position: absolute;
    top: -1.9rem;
    left: 1rem;
    margin: 0;
  }
  .page-about .ab-tl__year {
    font-size: 1.5rem;
  }
  .page-about .ab-tl__title {
    font-size: 1rem;
    line-height: 1.4;
  }
  .page-about .ab-tl__item .qa__body {
    padding: 0 1rem 1.25rem;
  }
  .page-about .ab-tl--now .ab-tl__item {
    border-left-color: var(--cyan);
    background: rgba(34, 211, 238, .07);
  }
  .page-about .ab-coop__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 3.5rem;
  }
  .page-about .ab-origin__figure {
    margin-top: 1.5rem;
  }
}

/* ---------- 减动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .ab-layer:nth-child(even),
  .page-about .ab-layer.card--accent,
  .page-about .ab-team__grid > :nth-child(2),
  .page-about .ab-team__grid > :nth-child(4) {
    transform: none;
  }
  .page-about a,
  .page-about summary {
    transition-duration: 120ms;
  }
}