.page-about {
  --about-stem: 84px;
  --about-gap: 20px;
  background: var(--paper);
  color: var(--black);
}

.page-about .section {
  padding: 52px 0;
  border-top: 1px solid var(--rule);
}

.page-about .section:first-of-type {
  border-top: 0;
}

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

.page-about .section__head h2 {
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(24px, 4.2vw, 42px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  margin: 10px 0 0;
}

.page-about .section__head p {
  margin: 14px 0 0;
  font-family: var(--sans-cond);
  font-size: 16px;
  line-height: 1.75;
  letter-spacing: 0.01em;
  color: var(--black);
  max-width: 68ch;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding: 26px 0 34px;
  border-bottom: 1px solid var(--rule);
}

.page-about .about-hero__lead .eyebrow {
  display: block;
}

.page-about .about-hero h1 {
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(30px, 7.4vw, 62px);
  line-height: 1.08;
  letter-spacing: -0.015em;
  margin: 12px 0 0;
}

.page-about .about-hero h1::after {
  content: "";
  display: block;
  width: 72px;
  height: 4px;
  margin-top: 20px;
  background: var(--brass);
  clip-path: polygon(0 0, 100% 0, calc(100% - 6px) 100%, 0 100%);
}

.page-about .about-hero .lede {
  margin: 20px 0 0;
  font-family: var(--sans-cond);
  font-size: 16px;
  line-height: 1.8;
  max-width: 56ch;
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  margin: 28px 0 0;
  background: var(--rule);
  border: 1px solid var(--rule);
}

.page-about .fact {
  background: var(--paper);
  padding: 16px 12px;
  display: flex;
  flex-direction: column-reverse;
  gap: 6px;
}

.page-about .fact dt {
  font-family: var(--mono);
  font-size: 11px;
  line-height: 1.5;
  letter-spacing: 0.06em;
  color: var(--gray);
}

.page-about .fact dd {
  margin: 0;
  font-family: var(--mono);
  font-size: clamp(24px, 5.6vw, 38px);
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
}

/* ---------- 年度卷宗时间轴 ---------- */

.page-about .ledger__grid {
  display: block;
}

.page-about .chronicle {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .chronicle__item {
  display: grid;
  grid-template-columns: var(--about-stem) minmax(0, 1fr);
  gap: var(--about-gap);
  padding: 20px 0;
  border-bottom: 1px solid var(--rule);
}

.page-about .chronicle__stem {
  position: relative;
  border-right: 1px solid var(--rule-invert);
  padding-right: 12px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .chronicle__stem::after {
  content: "";
  position: absolute;
  right: -3px;
  top: 10px;
  width: 5px;
  height: 5px;
  background: var(--brass);
  transform: rotate(45deg);
}

.page-about .chronicle__year {
  font-family: var(--mono);
  font-size: 12px;
  line-height: 1.4;
  letter-spacing: 0.02em;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
}

.page-about .chronicle__vol {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.06em;
  color: var(--gray);
}

.page-about .chronicle__body h3 {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 18px;
  line-height: 1.35;
  margin: 0;
  color: var(--ink);
}

.page-about .chronicle__body p {
  margin: 8px 0 0;
  font-family: var(--sans-cond);
  font-size: 15px;
  line-height: 1.78;
}

.page-about .ledger__figure {
  margin: 32px 0 0;
}

.page-about .ledger__figure .note,
.page-about .measure__figure .note,
.page-about .network__figure .note {
  margin: 10px 0 0;
}

/* ---------- 两级核定 ---------- */

.page-about .measure__figure {
  margin: 0 0 26px;
}

.page-about .measure__body p {
  margin: 0;
  font-family: var(--sans-cond);
  font-size: 16px;
  line-height: 1.85;
  letter-spacing: 0.01em;
  max-width: 72ch;
}

.page-about .tree-wrap {
  margin-top: 28px;
  padding: 20px 16px 14px;
  background: var(--paper-2);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%);
}

.page-about .tree-wrap .note {
  margin: 12px 0 0;
}

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

.page-about .tree__cap {
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  fill: var(--gray);
}

.page-about .tree__cell {
  fill: var(--paper);
  stroke: var(--rule-strong);
  stroke-width: 1;
  transition: fill 0.22s var(--ease), stroke 0.22s var(--ease);
}

.page-about .tree__t {
  font-family: var(--sans-cond);
  font-size: 17px;
  fill: var(--black);
  transition: fill 0.22s var(--ease);
}

.page-about .tree__cell--hub {
  fill: var(--ink);
  stroke: var(--ink);
}

.page-about .tree__t--hub {
  fill: var(--brass-lt);
  font-family: var(--serif);
  font-size: 19px;
  letter-spacing: 0.14em;
}

.page-about .tree__link {
  fill: none;
  stroke: var(--brass);
  stroke-width: 1.5;
  opacity: 0.7;
}

.page-about .tree__col:hover .tree__cell {
  fill: var(--ink-mid);
  stroke: var(--ink-mid);
}

.page-about .tree__col:hover .tree__t {
  fill: var(--brass-lt);
}

/* ---------- 协作网络 ---------- */

.page-about .network__grid {
  display: block;
}

.page-about .network__regions .eyebrow {
  display: block;
  margin-bottom: 12px;
}

.page-about .regions {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .regions__tag {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 16px;
  letter-spacing: 0.08em;
  color: var(--ink);
  padding: 10px 18px 10px 14px;
  background: var(--paper-2);
  border-left: 3px solid var(--brass);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 12px), calc(100% - 12px) 100%, 0 100%);
}

.page-about .regions__tag:nth-child(3n + 2) {
  background: var(--ink-mid);
  color: var(--paper);
  border-left-color: var(--brass-lt);
}

.page-about .regions__tag:nth-child(3n + 3) {
  background: var(--ink);
  color: var(--paper);
  border-left-color: var(--cinnabar);
}

.page-about .network__hint {
  margin: 16px 0 0;
  font-family: var(--sans-cond);
  font-size: 15px;
  line-height: 1.78;
  color: var(--gray);
  max-width: 60ch;
}

.page-about .network__figure {
  margin: 28px 0 0;
}

/* ---------- 岗位分工 ---------- */

.page-about .roster__wrap {
  overflow-x: auto;
  border-top: 2px solid var(--ink);
}

.page-about .roster__table {
  width: 100%;
  min-width: 520px;
  border-collapse: collapse;
  font-family: var(--sans-cond);
  font-size: 15px;
}

.page-about .roster__table caption {
  text-align: left;
  padding: 12px 0;
}

.page-about .roster__table th,
.page-about .roster__table td {
  text-align: left;
  padding: 14px 14px 14px 0;
  border-bottom: 1px solid var(--rule);
  vertical-align: top;
  line-height: 1.7;
}

.page-about .roster__table thead th {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--gray);
  font-weight: 400;
  border-bottom: 1px solid var(--rule-strong);
}

.page-about .roster__table tbody th {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 16px;
  color: var(--ink);
  white-space: nowrap;
}

.page-about .roster__table tbody tr:hover td,
.page-about .roster__table tbody tr:hover th {
  background: var(--paper-2);
}

.page-about .roster__table td.num {
  font-family: var(--mono);
  font-weight: 500;
  font-size: 22px;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.page-about .roster__table tbody tr:last-child td.num {
  color: var(--cinnabar);
}

/* ---------- 行业评价 ---------- */

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

.page-about .credential__item {
  background: var(--paper);
  padding: 22px 18px;
  border-left: 3px solid var(--brass);
}

.page-about .credential__label {
  margin: 0;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--gray);
}

.page-about .credential__value {
  margin: 10px 0 0;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 18px;
  line-height: 1.4;
  color: var(--ink);
}

.page-about .credential__meta {
  margin: 8px 0 0;
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.03em;
  color: var(--cinnabar);
}

/* ---------- 核校节奏 ---------- */

.page-about .rhythm__switch {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 22px;
}

.page-about .rhythm__btn {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  padding: 9px 14px;
}

.page-about .rhythm__grid {
  display: grid;
  gap: 16px;
}

.page-about .rhythm__card {
  padding: 20px 18px 22px;
  background: var(--paper-2);
  border-top: 3px solid var(--ink);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 16px), calc(100% - 16px) 100%, 0 100%);
}

.page-about .rhythm__card[hidden] {
  display: none;
}

.page-about .rhythm__no {
  margin: 0;
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--brass);
}

.page-about .rhythm__card h3 {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 19px;
  line-height: 1.35;
  margin: 8px 0 0;
  color: var(--ink);
}

.page-about .rhythm__card p {
  margin: 10px 0 0;
  font-family: var(--sans-cond);
  font-size: 15px;
  line-height: 1.78;
}

/* ---------- 下一步 ---------- */

.page-about .next {
  border-top: 1px solid var(--rule);
}

.page-about .next__panel {
  background: var(--ink);
  color: var(--paper);
  padding: 32px 22px 30px;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 26px), calc(100% - 26px) 100%, 0 100%);
}

.page-about .next__panel .eyebrow {
  display: block;
  color: var(--brass-lt);
}

.page-about .next__panel h2 {
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(22px, 4vw, 36px);
  line-height: 1.2;
  margin: 10px 0 0;
  color: var(--paper);
}

.page-about .next__panel p {
  margin: 14px 0 0;
  font-family: var(--sans-cond);
  font-size: 16px;
  line-height: 1.8;
  color: var(--paper-2);
  max-width: 62ch;
}

.page-about .next__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.page-about .next__ghost {
  border-color: var(--brass-lt);
  color: var(--brass-lt);
}

.page-about .next__foot {
  margin: 18px 0 0;
}

.page-about .next__foot a {
  color: var(--ink);
  text-decoration: underline;
  text-decoration-color: var(--brass);
  text-underline-offset: 3px;
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-about {
    --about-stem: 118px;
    --about-gap: 28px;
  }

  .page-about .section {
    padding: 64px 0;
  }

  .page-about .about-hero {
    padding: 36px 0 46px;
  }

  .page-about .about-hero__facts {
    margin-top: 34px;
  }

  .page-about .fact {
    padding: 20px 18px;
  }

  .page-about .chronicle__item {
    padding: 24px 0;
  }

  .page-about .credit-card,
  .page-about .credential__item {
    padding: 26px 24px;
  }

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

  .page-about .next__panel {
    padding: 44px 36px 40px;
  }
}

@media (min-width: 900px) {
  .page-about .section__head {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    column-gap: 56px;
    align-items: end;
  }

  .page-about .section__head .eyebrow {
    grid-column: 1 / -1;
  }

  .page-about .section__head h2 {
    margin-top: 12px;
  }

  .page-about .section__head p {
    margin-top: 0;
  }

  .page-about .about-hero {
    display: grid;
    grid-template-columns: minmax(0, 1.45fr) minmax(0, 1fr);
    column-gap: 64px;
    align-items: end;
  }

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

  .page-about .ledger__grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 330px);
    column-gap: 60px;
    align-items: start;
  }

  .page-about .ledger__figure {
    margin-top: 0;
    position: sticky;
    top: calc(var(--masthead-h) + 24px);
  }

  .page-about .network__grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr);
    column-gap: 56px;
    align-items: start;
  }

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

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

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

  .page-about .next__panel {
    display: grid;
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
    column-gap: 56px;
    align-items: center;
  }

  .page-about .next__actions {
    margin-top: 0;
    justify-content: flex-end;
  }
}

@media (min-width: 1120px) {
  .page-about .section {
    padding: 78px 0;
  }

  .page-about .measure__figure {
    margin-bottom: 34px;
  }

  .page-about .tree-wrap {
    padding: 28px 28px 18px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tree__cell,
  .page-about .tree__t {
    transition: none;
  }
}