.page-about {
  --about-pad: 16px;
  --about-radius: 0;
  --about-card: rgba(18, 56, 46, .55);
}

.page-about img {
  display: block;
  max-width: 100%;
  height: auto;
}

.page-about .about-shell {
  width: 100%;
  max-width: 1180px;
  margin-inline: auto;
  padding-inline: var(--about-pad);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  padding-block: 18px 40px;
  background:
    radial-gradient(120% 80% at 82% -10%, rgba(102, 199, 217, .16), transparent 62%),
    radial-gradient(90% 70% at 6% 0%, rgba(242, 107, 56, .12), transparent 58%),
    linear-gradient(180deg, var(--forest), var(--ink) 82%);
  border-bottom: 1px solid var(--line);
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(to right, rgba(216, 181, 106, .07) 1px, transparent 1px);
  background-size: 84px 100%;
  opacity: .55;
}

.page-about .about-hero .about-shell {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__grid {
  display: grid;
  gap: 26px;
  margin-top: 22px;
}

.page-about .about-hero h1 {
  margin: 12px 0 16px;
  font-size: clamp(34px, 8.4vw, 78px);
  font-weight: 300;
  line-height: 1.02;
  letter-spacing: -.02em;
  color: var(--sand);
}

.page-about .about-hero .lede {
  max-width: 52ch;
  color: var(--dim);
  margin: 0;
}

.page-about .about-hero__facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-fact {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 16px 14px;
  background: var(--track);
}

.page-about .about-fact__num {
  font-family: var(--font-mono);
  font-size: clamp(24px, 5vw, 34px);
  font-weight: 300;
  line-height: 1;
  letter-spacing: -.03em;
  color: var(--gold);
  font-variant-numeric: tabular-nums;
}

.page-about .about-fact__num em {
  font-style: normal;
  font-size: .58em;
  color: var(--orange);
  margin-left: 2px;
}

.page-about .about-fact__cap {
  font-size: 12px;
  line-height: 1.5;
  color: var(--dim);
}

.page-about .about-hero__figure {
  margin: 30px 0 0;
  border: 1px solid var(--line-strong);
}

/* ---------- 主体两栏 ---------- */

.page-about .about-body {
  padding-block: 30px 64px;
}

.page-about .about-index {
  border-top: 1px solid var(--line-strong);
  border-bottom: 1px solid var(--line);
  margin-bottom: 26px;
}

.page-about .about-index__summary {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding-block: 12px;
  cursor: pointer;
  list-style: none;
}

.page-about .about-index__summary::-webkit-details-marker {
  display: none;
}

.page-about .about-index__hint {
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--ice);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0 0 12px;
  display: grid;
  gap: 2px;
}

.page-about .about-index__link {
  display: flex;
  gap: 10px;
  align-items: baseline;
  padding: 10px 4px;
  min-height: 44px;
  text-decoration: none;
  color: var(--dim);
  font-size: 15px;
  border-left: 2px solid transparent;
  transition: color 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .about-index__link .num {
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--moss);
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  color: var(--sand);
  border-left-color: var(--gold);
}

.page-about .about-index__link:hover .num,
.page-about .about-index__link:focus-visible .num {
  color: var(--orange);
}

/* ---------- 章节 ---------- */

.page-about .about-sec {
  padding-block: 38px;
  border-top: 1px solid var(--line);
}

.page-about .about-sec:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-sec__head {
  margin-bottom: 22px;
}

.page-about .about-sec h2 {
  margin: 10px 0 0;
  font-size: clamp(25px, 5vw, 42px);
  font-weight: 300;
  line-height: 1.12;
  letter-spacing: -.015em;
  color: var(--sand);
}

.page-about .about-sec__body p {
  margin: 0 0 14px;
  color: var(--dim);
  max-width: 62ch;
}

.page-about .about-sec__body p:last-child {
  margin-bottom: 0;
}

/* 定位区数据条 */

.page-about .about-inline-stats {
  list-style: none;
  margin: 24px 0 0;
  padding: 16px 0 0;
  border-top: 1px solid var(--line);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 18px;
}

.page-about .about-inline-stats li {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .about-inline-stats .num {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 300;
  color: var(--ice);
  font-variant-numeric: tabular-nums;
}

.page-about .about-inline-stats__cap {
  font-size: 12px;
  color: var(--dim-soft);
}

/* ---------- 时间轴 ---------- */

.page-about .eras {
  list-style: none;
  margin: 8px 0 0;
  padding: 0;
}

.page-about .era {
  position: relative;
  border-top: 1px solid var(--line);
}

.page-about .era__summary {
  display: grid;
  grid-template-columns: 62px minmax(0, 1fr);
  gap: 12px;
  align-items: baseline;
  padding: 15px 4px;
  min-height: 44px;
  cursor: pointer;
  list-style: none;
}

.page-about .era__summary::-webkit-details-marker {
  display: none;
}

.page-about .era__year {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 500;
  letter-spacing: -.01em;
  color: var(--gold);
  font-variant-numeric: tabular-nums;
}

.page-about .era__title {
  font-size: 17px;
  font-weight: 400;
  color: var(--sand);
  line-height: 1.4;
}

.page-about .era__summary:hover .era__title,
.page-about .era__summary:focus-visible .era__title {
  color: var(--gold);
}

.page-about .era__body {
  padding: 0 4px 18px 74px;
}

.page-about .era__body p {
  margin: 0;
  color: var(--dim);
  font-size: 15px;
  max-width: 58ch;
}

/* ---------- 资料体系卡片 ---------- */

.page-about .arc-grid {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .arc-card {
  display: grid;
  gap: 6px;
  padding: 18px 16px 20px;
  background: var(--forest);
  border-top: 2px solid transparent;
  transition: border-color 180ms var(--ease), background-color 180ms var(--ease);
}

.page-about .arc-card:hover {
  background: var(--track);
  border-top-color: var(--gold);
}

.page-about .arc-card__no {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--orange);
}

.page-about .arc-card__title {
  margin: 0;
  font-size: 18px;
  font-weight: 400;
  color: var(--sand);
  letter-spacing: .01em;
}

.page-about .arc-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--dim);
}

/* ---------- 团队 ---------- */

.page-about .about-team {
  display: grid;
  gap: 24px;
  margin-top: 4px;
}

.page-about .about-team__text p {
  margin: 0 0 14px;
  color: var(--dim);
  max-width: 58ch;
}

.page-about .about-team__figure {
  margin: 0;
  border: 1px solid var(--line-strong);
}

.page-about .stat-row {
  list-style: none;
  margin: 22px 0 0;
  padding: 16px 0 0;
  border-top: 1px solid var(--line);
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px 10px;
}

.page-about .stat-row li {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .stat-row__num {
  font-family: var(--font-mono);
  font-size: clamp(24px, 4.6vw, 32px);
  font-weight: 300;
  line-height: 1;
  color: var(--gold);
  font-variant-numeric: tabular-nums;
}

.page-about .stat-row__cap {
  font-size: 12px;
  color: var(--dim-soft);
}

/* ---------- 合作生态 ---------- */

.page-about .about-partners__figure {
  margin: 20px 0 22px;
  border: 1px solid var(--line-strong);
}

.page-about .topic-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 14px;
}

.page-about .topic-tags .tag {
  min-height: 32px;
  display: inline-flex;
  align-items: center;
  padding: 4px 12px;
  font-size: 13px;
}

.page-about .about-sec .note {
  margin: 0;
  padding-top: 12px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  line-height: 1.7;
  color: var(--dim-soft);
  max-width: 60ch;
}

/* ---------- 服务对象 ---------- */

.page-about .who-grid {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .who-card {
  padding: 18px 16px;
  background: var(--track);
}

.page-about .who-card__title {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 400;
  letter-spacing: .02em;
  color: var(--gold);
}

.page-about .who-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--dim);
}

/* ---------- 收束 ---------- */

.page-about .about-cta {
  margin-top: 44px;
  padding: 30px 20px 32px;
  background:
    linear-gradient(135deg, rgba(242, 107, 56, .13), transparent 58%),
    var(--forest);
  border: 1px solid var(--line-strong);
}

.page-about .about-cta__title {
  margin: 10px 0 12px;
  font-size: clamp(22px, 4.4vw, 32px);
  font-weight: 300;
  line-height: 1.2;
  color: var(--sand);
}

.page-about .about-cta__text {
  margin: 0 0 22px;
  color: var(--dim);
  max-width: 56ch;
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .about-cta__actions .btn {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

/* ---------- 断点 ---------- */

@media (min-width: 560px) {
  .page-about .about-inline-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 720px) {
  .page-about .about-shell {
    padding-inline: 24px;
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.5fr) minmax(240px, .9fr);
    gap: 36px;
    align-items: end;
  }

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

  .page-about .arc-card--wide {
    grid-column: 1 / -1;
  }

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

  .page-about .who-card:last-child {
    grid-column: 1 / -1;
  }

  .page-about .era::before {
    content: "";
    position: absolute;
    left: 74px;
    top: 10px;
    bottom: 10px;
    width: 1px;
    background: var(--line-strong);
    transform: skewX(-8deg);
  }

  .page-about .about-cta {
    padding: 38px 30px 40px;
  }
}

@media (min-width: 960px) {
  .page-about .about-body {
    display: grid;
    grid-template-columns: 172px minmax(0, 1fr);
    gap: 56px;
    align-items: start;
    padding-block: 40px 88px;
  }

  .page-about .about-index {
    position: sticky;
    top: calc(var(--bar-h) + 24px);
    margin-bottom: 0;
    border-bottom: 0;
  }

  .page-about .about-index__summary {
    cursor: default;
    pointer-events: none;
  }

  .page-about .about-index:not([open]) > .about-index__list {
    display: grid;
  }

  .page-about .about-index__link {
    font-size: 14px;
  }

  .page-about .about-sec {
    padding-block: 52px;
  }

  .page-about .about-team {
    grid-template-columns: minmax(0, 1fr) minmax(0, .82fr);
    gap: 32px;
    align-items: start;
  }

  .page-about .arc-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .arc-card--wide {
    grid-column: 1 / -1;
  }

  .page-about .who-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .who-card:last-child {
    grid-column: auto;
  }

  .page-about .stat-row {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .arc-card,
  .page-about .about-index__link {
    transition: none;
  }
}
<<<END>>>