.page-about {
  --about-tick: rgba(53, 242, 200, .28);
  --about-line: rgba(42, 70, 64, .9);
  --about-dim: rgba(143, 168, 160, .55);
  color: var(--chalk);
  background: var(--ink);
}

/* ---------- 页首 ---------- */
.page-about .about-masthead {
  padding-top: calc(var(--header-h) + 34px);
  padding-bottom: 44px;
}

.page-about .masthead-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 26px;
  margin-top: 22px;
}

.page-about .about-h1 {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(2rem, 7vw, 3.75rem);
  line-height: 1.05;
  letter-spacing: -0.01em;
  text-transform: uppercase;
  margin: 14px 0 18px;
}

.page-about .about-h1 .cn {
  display: block;
  font-size: .82em;
  text-transform: none;
  color: var(--cyan);
}

.page-about .lede {
  max-width: 60ch;
  color: var(--mist);
  font-size: 1rem;
  line-height: 1.8;
}

.page-about .masthead-side {
  border: var(--edge);
  background: var(--turf);
  padding: 18px 20px 20px;
  box-shadow: var(--shadow-hard);
}

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

.page-about .about-jump li {
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-jump li:last-child {
  border-bottom: 0;
}

.page-about .about-jump a {
  display: block;
  padding: 10px 2px;
  min-height: 44px;
  font-size: .875rem;
  color: var(--chalk);
  text-decoration: none;
  transition: color var(--ease), transform var(--ease);
}

.page-about .about-jump a::before {
  content: "→";
  font-family: var(--font-mono);
  margin-right: 10px;
  color: var(--cyan);
}

.page-about .about-jump a:hover,
.page-about .about-jump a:focus-visible {
  color: var(--cyan);
  transform: translateX(3px);
}

/* ---------- 章节通用 ---------- */
.page-about .chapter {
  padding: 54px 0 58px;
  background: var(--ink);
}

.page-about .chapter--turf {
  background: var(--turf-deep);
}

.page-about .chapter--paper {
  background: var(--paper);
  color: var(--paper-ink);
}

.page-about .chapter--paper .chapter__title,
.page-about .chapter--paper .chapter__kicker,
.page-about .chapter--paper .prose {
  color: var(--paper-ink);
}

.page-about .chapter--paper .chapter__lede,
.page-about .chapter--paper .figure__caption {
  color: #42524C;
}

.page-about .chapter--paper .chapter__index {
  color: #7E918A;
}

.page-about .chapter--boundary {
  background: var(--turf);
  border-top: var(--edge);
}

.page-about .chapter__index {
  color: var(--mist);
  transition: color var(--ease);
}

.page-about .chapter[data-chapter].is-active .chapter__index,
.page-about .chapter:target .chapter__index {
  color: var(--cyan);
}

.page-about .chapter__title {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(1.5rem, 4.6vw, 2.4rem);
  line-height: 1.14;
  letter-spacing: -0.01em;
  margin: 6px 0 14px;
  max-width: 24ch;
}

.page-about .chapter__lede {
  max-width: 66ch;
  color: var(--mist);
  line-height: 1.8;
}

.page-about .chapter__note {
  margin-top: 26px;
  padding-left: 16px;
  border-left: 2px solid var(--cyan);
  color: var(--mist);
  font-size: .875rem;
  line-height: 1.8;
  max-width: 62ch;
}

.page-about .chapter--paper .chapter__note {
  color: #42524C;
}

.page-about .chapter__note--last {
  margin-top: 30px;
}

.page-about .chapter__note a {
  color: var(--cyan);
}

.page-about .chapter--paper .chapter__note a {
  color: #0E6B57;
}

/* ---------- 起点双栏 ---------- */
.page-about .origin-grid {
  margin-top: 28px;
}

.page-about .origin-col {
  border: var(--edge);
  background: var(--turf-deep);
  padding: 22px 22px 24px;
  box-shadow: var(--shadow-hard);
  transition: transform var(--ease), box-shadow var(--ease), border-color var(--ease);
}

.page-about .origin-col--alt {
  border-color: var(--about-line);
  background: var(--turf);
}

.page-about .origin-col:hover,
.page-about .origin-col:focus-within {
  transform: translateY(-2px);
  border-color: var(--cyan);
  box-shadow: var(--shadow-hard-lift);
}

.page-about .origin-col__title {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.25rem;
  letter-spacing: .01em;
  margin: 10px 0 12px;
}

.page-about .origin-col__meta {
  margin-top: 16px;
  padding-top: 12px;
  border-top: 1px solid var(--about-line);
  font-size: .8125rem;
  color: var(--mist);
}

.page-about .eyebrow--cyan {
  color: var(--cyan);
}

.page-about .chapter--paper .eyebrow--cyan {
  color: #0E6B57;
}

/* ---------- 覆盖范围 ---------- */
.page-about .coverage-grid {
  margin-top: 28px;
}

.page-about .coverage-figure {
  margin-bottom: 24px;
  border: var(--edge);
  background: #0F241E;
}

.page-about .coverage-list {
  margin: 0;
  border-top: 2px solid var(--steel);
}

.page-about .coverage-row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 4px;
  padding: 14px 0;
  border-bottom: 1px solid var(--about-line);
}

.page-about .coverage-row__key {
  font-family: var(--font-display);
  font-size: 1rem;
  letter-spacing: .02em;
  color: var(--chalk);
}

.page-about .coverage-row__val {
  margin: 0;
  font-size: .9375rem;
  color: var(--cyan);
}

.page-about .coverage-row__note {
  margin: 0;
  font-size: .8125rem;
  color: var(--mist);
  line-height: 1.7;
}

.page-about .coverage-row--total .coverage-row__key,
.page-about .coverage-row--total .coverage-row__val {
  font-weight: 700;
  color: var(--amber);
}

.page-about .chapter--paper .coverage-row__key {
  color: var(--paper-ink);
}

.page-about .chapter--paper .coverage-row__val {
  color: #0E6B57;
}

.page-about .chapter--paper .coverage-row__note {
  color: #4A5A54;
}

.page-about .chapter--paper .coverage-row--total .coverage-row__key,
.page-about .chapter--paper .coverage-row--total .coverage-row__val {
  color: #8A5F14;
}

.page-about .chapter--paper .coverage-list {
  border-top-color: #B9C7C1;
}

.page-about .chapter--paper .coverage-row {
  border-bottom-color: #C6D2CD;
}

.page-about .chapter--paper .coverage-figure {
  border-color: #B9C7C1;
  background: #DCE5E0;
}

.page-about .coverage-panel {
  margin-bottom: 18px;
}

.page-about .coverage-stat {
  display: flex;
  align-items: baseline;
  gap: 8px;
  margin: 0 0 12px;
}

.page-about .coverage-stat__num {
  font-size: 2.4rem;
  line-height: 1;
  color: var(--cyan);
  letter-spacing: -0.02em;
}

.page-about .coverage-stat__unit {
  font-size: .8125rem;
  color: var(--mist);
  letter-spacing: .08em;
}

.page-about .coverage-note {
  margin: 0;
  font-size: .875rem;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .chapter--paper .coverage-stat__num {
  color: #0E6B57;
}

.page-about .chapter--paper .coverage-stat__unit,
.page-about .chapter--paper .coverage-note {
  color: #4A5A54;
}

/* ---------- 流程四段 ---------- */
.page-about .flow-figure {
  margin: 26px 0 30px;
  border: var(--edge);
  background: var(--turf);
}

.page-about .flow-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  counter-reset: flow;
}

.page-about .flow-step {
  position: relative;
  border: 2px solid var(--steel);
  background: var(--turf-deep);
  padding: 20px 20px 22px;
  box-shadow: 4px 4px 0 rgba(0, 0, 0, .5);
  transition: transform var(--ease), border-color var(--ease), box-shadow var(--ease);
}

.page-about .flow-step::after {
  content: "";
  position: absolute;
  right: 0;
  top: 0;
  width: 46px;
  height: 46px;
  background: linear-gradient(225deg, var(--about-tick), transparent 62%);
  pointer-events: none;
}

.page-about .flow-step:hover,
.page-about .flow-step:focus-within {
  transform: translateY(-2px);
  border-color: var(--cyan);
  box-shadow: var(--shadow-hard-lift);
}

.page-about .flow-step__idx {
  display: inline-block;
  font-size: 1.5rem;
  color: var(--cyan);
  letter-spacing: .04em;
}

.page-about .flow-step__title {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.0625rem;
  letter-spacing: .03em;
  margin: 8px 0 10px;
  color: var(--chalk);
}

.page-about .flow-step__body {
  margin: 0;
  font-size: .875rem;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .note--inline {
  margin-top: 26px;
}

/* ---------- 时间轴 ---------- */
.page-about .timeline-wrap {
  position: relative;
  margin-top: 30px;
  padding-top: 18px;
}

.page-about .timeline-bg {
  position: absolute;
  inset: 0;
  margin: 0;
  overflow: hidden;
  opacity: .16;
  pointer-events: none;
}

.page-about .timeline-bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(.5);
}

.page-about .timeline {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}

.page-about .timeline__node {
  position: relative;
  padding: 18px 0 20px 26px;
  border-left: 2px solid var(--about-tick);
}

.page-about .timeline__node::before {
  content: "";
  position: absolute;
  left: -7px;
  top: 26px;
  width: 12px;
  height: 12px;
  background: var(--ink);
  border: 2px solid var(--cyan);
  border-radius: 50%;
}

.page-about .timeline__node:last-child {
  border-left-color: transparent;
}

.page-about .timeline__num {
  display: block;
  font-size: 1.125rem;
  letter-spacing: .08em;
  color: var(--cyan);
}

.page-about .timeline__name {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.0625rem;
  letter-spacing: .02em;
  margin: 6px 0 8px;
  color: var(--chalk);
}

.page-about .timeline__desc {
  margin: 0;
  font-size: .875rem;
  line-height: 1.85;
  color: var(--mist);
  max-width: 52ch;
}

/* ---------- 团队表格 ---------- */
.page-about .team-grid {
  margin-top: 26px;
}

.page-about .team-table {
  width: 100%;
  margin-bottom: 22px;
}

.page-about .team-table th[scope="row"] {
  color: var(--chalk);
  font-weight: 500;
  white-space: nowrap;
}

.page-about .team-aside .note + .note {
  margin-top: 16px;
}

/* ---------- 地区长文 ---------- */
.page-about .region-prose p {
  max-width: 64ch;
}

.page-about .region-prose p + p {
  margin-top: 18px;
}

/* ---------- 边界收尾 ---------- */
.page-about .boundary-grid {
  margin-top: 24px;
}

.page-about .boundary-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 2px solid var(--steel);
}

.page-about .boundary-item {
  position: relative;
  padding: 14px 0 14px 30px;
  border-bottom: 1px solid var(--about-line);
  font-size: .9375rem;
  line-height: 1.8;
  color: var(--chalk);
}

.page-about .boundary-item::before {
  content: "×";
  position: absolute;
  left: 0;
  top: 13px;
  font-family: var(--font-mono);
  font-size: 1rem;
  color: var(--amber);
}

.page-about .boundary-panel {
  margin-top: 4px;
}

.page-about .boundary-panel .panel__foot .btn {
  display: inline-block;
}

/* ---------- 响应式 ---------- */
@media (min-width: 768px) {
  .page-about .about-masthead {
    padding-top: calc(var(--header-h) + 52px);
    padding-bottom: 60px;
  }

  .page-about .masthead-grid {
    grid-template-columns: 7fr 4fr;
    gap: 40px;
    align-items: start;
    margin-top: 30px;
  }

  .page-about .chapter {
    padding: 72px 0 78px;
  }

  .page-about .coverage-row {
    grid-template-columns: minmax(140px, 1fr) auto;
    align-items: baseline;
    gap: 6px 20px;
  }

  .page-about .coverage-row__note {
    grid-column: 2;
    text-align: right;
  }

  .page-about .flow-list {
    grid-template-columns: repeat(2, 1fr);
    gap: 18px;
  }

  .page-about .timeline {
    grid-template-columns: repeat(2, 1fr);
    gap: 0 30px;
  }

  .page-about .timeline__node:nth-child(odd) {
    border-left-color: transparent;
  }

  .page-about .timeline__node:nth-child(odd)::before {
    display: none;
  }
}

@media (min-width: 1024px) {
  .page-about .masthead-grid {
    grid-template-columns: 8fr 4fr;
    gap: 56px;
  }

  .page-about .about-h1 {
    font-size: clamp(3rem, 5.2vw, 3.9rem);
  }

  .page-about .flow-list {
    grid-template-columns: repeat(4, 1fr);
  }

  .page-about .timeline {
    grid-template-columns: repeat(5, 1fr);
    gap: 0 22px;
    padding-top: 12px;
  }

  .page-about .timeline__node {
    padding: 22px 8px 8px 0;
    border-left: 0;
    border-top: 2px solid var(--about-tick);
  }

  .page-about .timeline__node:nth-child(odd) {
    border-top-color: var(--about-tick);
  }

  .page-about .timeline__node::before {
    left: 0;
    top: -8px;
  }

  .page-about .timeline__node:nth-child(odd)::before {
    display: block;
  }

  .page-about .timeline__node:hover::before,
  .page-about .timeline__node:focus-within::before {
    background: var(--cyan);
  }

  .page-about .timeline__node:hover .timeline__desc,
  .page-about .timeline__node:focus-within .timeline__desc {
    color: var(--chalk);
  }

  .page-about .timeline__desc {
    font-size: .8125rem;
    line-height: 1.8;
  }
}

@media (min-width: 1440px) {
  .page-about .flow-list {
    gap: 22px;
  }

  .page-about .timeline {
    gap: 0 30px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .origin-col,
  .page-about .flow-step,
  .page-about .about-jump a,
  .page-about .chapter__index {
    transition: none;
  }

  .page-about .origin-col:hover,
  .page-about .flow-step:hover {
    transform: none;
  }
}

.page-about {
  --about-tick: rgba(53, 242, 200, .28);
  --about-line: rgba(42, 70, 64, .9);
  --about-dim: rgba(143, 168, 160, .55);
  color: var(--chalk);
  background: var(--ink);
}

/* ---------- 页首 ---------- */
.page-about .about-masthead {
  padding-top: calc(var(--header-h) + 34px);
  padding-bottom: 44px;
}

.page-about .masthead-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 26px;
  margin-top: 22px;
}

.page-about .about-h1 {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(2rem, 7vw, 3.75rem);
  line-height: 1.05;
  letter-spacing: -0.01em;
  text-transform: uppercase;
  margin: 14px 0 18px;
}

.page-about .about-h1 .cn {
  display: block;
  font-size: .82em;
  text-transform: none;
  color: var(--cyan);
}

.page-about .lede {
  max-width: 60ch;
  color: var(--mist);
  font-size: 1rem;
  line-height: 1.8;
}

.page-about .masthead-side {
  border: var(--edge);
  background: var(--turf);
  padding: 18px 20px 20px;
  box-shadow: var(--shadow-hard);
}

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

.page-about .about-jump li {
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-jump li:last-child {
  border-bottom: 0;
}

.page-about .about-jump a {
  display: block;
  padding: 10px 2px;
  min-height: 44px;
  font-size: .875rem;
  color: var(--chalk);
  text-decoration: none;
  transition: color var(--ease), transform var(--ease);
}

.page-about .about-jump a::before {
  content: "→";
  font-family: var(--font-mono);
  margin-right: 10px;
  color: var(--cyan);
}

.page-about .about-jump a:hover,
.page-about .about-jump a:focus-visible {
  color: var(--cyan);
  transform: translateX(3px);
}

/* ---------- 章节通用 ---------- */
.page-about .chapter {
  padding: 54px 0 58px;
  background: var(--ink);
}

.page-about .chapter--turf {
  background: var(--turf-deep);
}

.page-about .chapter--paper {
  background: var(--paper);
  color: var(--paper-ink);
}

.page-about .chapter--paper .chapter__title,
.page-about .chapter--paper .chapter__kicker,
.page-about .chapter--paper .prose {
  color: var(--paper-ink);
}

.page-about .chapter--paper .chapter__lede,
.page-about .chapter--paper .figure__caption {
  color: #42524C;
}

.page-about .chapter--paper .chapter__index {
  color: #7E918A;
}

.page-about .chapter--boundary {
  background: var(--turf);
  border-top: var(--edge);
}

.page-about .chapter__index {
  color: var(--mist);
  transition: color var(--ease);
}

.page-about .chapter[data-chapter].is-active .chapter__index,
.page-about .chapter:target .chapter__index {
  color: var(--cyan);
}

.page-about .chapter__title {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(1.5rem, 4.6vw, 2.4rem);
  line-height: 1.14;
  letter-spacing: -0.01em;
  margin: 6px 0 14px;
  max-width: 24ch;
}

.page-about .chapter__lede {
  max-width: 66ch;
  color: var(--mist);
  line-height: 1.8;
}

.page-about .chapter__note {
  margin-top: 26px;
  padding-left: 16px;
  border-left: 2px solid var(--cyan);
  color: var(--mist);
  font-size: .875rem;
  line-height: 1.8;
  max-width: 62ch;
}

.page-about .chapter--paper .chapter__note {
  color: #42524C;
}

.page-about .chapter__note--last {
  margin-top: 30px;
}

.page-about .chapter__note a {
  color: var(--cyan);
}

.page-about .chapter--paper .chapter__note a {
  color: #0E6B57;
}

/* ---------- 起点双栏 ---------- */
.page-about .origin-grid {
  margin-top: 28px;
}

.page-about .origin-col {
  border: var(--edge);
  background: var(--turf-deep);
  padding: 22px 22px 24px;
  box-shadow: var(--shadow-hard);
  transition: transform var(--ease), box-shadow var(--ease), border-color var(--ease);
}

.page-about .origin-col--alt {
  border-color: var(--about-line);
  background: var(--turf);
}

.page-about .origin-col:hover,
.page-about .origin-col:focus-within {
  transform: translateY(-2px);
  border-color: var(--cyan);
  box-shadow: var(--shadow-hard-lift);
}

.page-about .origin-col__title {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.25rem;
  letter-spacing: .01em;
  margin: 10px 0 12px;
}

.page-about .origin-col__meta {
  margin-top: 16px;
  padding-top: 12px;
  border-top: 1px solid var(--about-line);
  font-size: .8125rem;
  color: var(--mist);
}

.page-about .eyebrow--cyan {
  color: var(--cyan);
}

.page-about .chapter--paper .eyebrow--cyan {
  color: #0E6B57;
}

/* ---------- 覆盖范围 ---------- */
.page-about .coverage-grid {
  margin-top: 28px;
}

.page-about .coverage-figure {
  margin-bottom: 24px;
  border: var(--edge);
  background: #0F241E;
}

.page-about .coverage-list {
  margin: 0;
  border-top: 2px solid var(--steel);
}

.page-about .coverage-row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 4px;
  padding: 14px 0;
  border-bottom: 1px solid var(--about-line);
}

.page-about .coverage-row__key {
  font-family: var(--font-display);
  font-size: 1rem;
  letter-spacing: .02em;
  color: var(--chalk);
}

.page-about .coverage-row__val {
  margin: 0;
  font-size: .9375rem;
  color: var(--cyan);
}

.page-about .coverage-row__note {
  margin: 0;
  font-size: .8125rem;
  color: var(--mist);
  line-height: 1.7;
}

.page-about .coverage-row--total .coverage-row__key,
.page-about .coverage-row--total .coverage-row__val {
  font-weight: 700;
  color: var(--amber);
}

.page-about .chapter--paper .coverage-row__key {
  color: var(--paper-ink);
}

.page-about .chapter--paper .coverage-row__val {
  color: #0E6B57;
}

.page-about .chapter--paper .coverage-row__note {
  color: #4A5A54;
}

.page-about .chapter--paper .coverage-row--total .coverage-row__key,
.page-about .chapter--paper .coverage-row--total .coverage-row__val {
  color: #8A5F14;
}

.page-about .chapter--paper .coverage-list {
  border-top-color: #B9C7C1;
}

.page-about .chapter--paper .coverage-row {
  border-bottom-color: #C6D2CD;
}

.page-about .chapter--paper .coverage-figure {
  border-color: #B9C7C1;
  background: #DCE5E0;
}

.page-about .coverage-panel {
  margin-bottom: 18px;
}

.page-about .coverage-stat {
  display: flex;
  align-items: baseline;
  gap: 8px;
  margin: 0 0 12px;
}

.page-about .coverage-stat__num {
  font-size: 2.4rem;
  line-height: 1;
  color: var(--cyan);
  letter-spacing: -0.02em;
}

.page-about .coverage-stat__unit {
  font-size: .8125rem;
  color: var(--mist);
  letter-spacing: .08em;
}

.page-about .coverage-note {
  margin: 0;
  font-size: .875rem;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .chapter--paper .coverage-stat__num {
  color: #0E6B57;
}

.page-about .chapter--paper .coverage-stat__unit,
.page-about .chapter--paper .coverage-note {
  color: #4A5A54;
}

/* ---------- 流程四段 ---------- */
.page-about .flow-figure {
  margin: 26px 0 30px;
  border: var(--edge);
  background: var(--turf);
}

.page-about .flow-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  counter-reset: flow;
}

.page-about .flow-step {
  position: relative;
  border: 2px solid var(--steel);
  background: var(--turf-deep);
  padding: 20px 20px 22px;
  box-shadow: 4px 4px 0 rgba(0, 0, 0, .5);
  transition: transform var(--ease), border-color var(--ease), box-shadow var(--ease);
}

.page-about .flow-step::after {
  content: "";
  position: absolute;
  right: 0;
  top: 0;
  width: 46px;
  height: 46px;
  background: linear-gradient(225deg, var(--about-tick), transparent 62%);
  pointer-events: none;
}

.page-about .flow-step:hover,
.page-about .flow-step:focus-within {
  transform: translateY(-2px);
  border-color: var(--cyan);
  box-shadow: var(--shadow-hard-lift);
}

.page-about .flow-step__idx {
  display: inline-block;
  font-size: 1.5rem;
  color: var(--cyan);
  letter-spacing: .04em;
}

.page-about .flow-step__title {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.0625rem;
  letter-spacing: .03em;
  margin: 8px 0 10px;
  color: var(--chalk);
}

.page-about .flow-step__body {
  margin: 0;
  font-size: .875rem;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .note--inline {
  margin-top: 26px;
}

/* ---------- 时间轴 ---------- */
.page-about .timeline-wrap {
  position: relative;
  margin-top: 30px;
  padding-top: 18px;
}

.page-about .timeline-bg {
  position: absolute;
  inset: 0;
  margin: 0;
  overflow: hidden;
  opacity: .16;
  pointer-events: none;
}

.page-about .timeline-bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(.5);
}

.page-about .timeline {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}

.page-about .timeline__node {
  position: relative;
  padding: 18px 0 20px 26px;
  border-left: 2px solid var(--about-tick);
}

.page-about .timeline__node::before {
  content: "";
  position: absolute;
  left: -7px;
  top: 26px;
  width: 12px;
  height: 12px;
  background: var(--ink);
  border: 2px solid var(--cyan);
  border-radius: 50%;
}

.page-about .timeline__node:last-child {
  border-left-color: transparent;
}

.page-about .timeline__num {
  display: block;
  font-size: 1.125rem;
  letter-spacing: .08em;
  color: var(--cyan);
}

.page-about .timeline__name {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.0625rem;
  letter-spacing: .02em;
  margin: 6px 0 8px;
  color: var(--chalk);
}

.page-about .timeline__desc {
  margin: 0;
  font-size: .875rem;
  line-height: 1.85;
  color: var(--mist);
  max-width: 52ch;
}

/* ---------- 团队表格 ---------- */
.page-about .team-grid {
  margin-top: 26px;
}

.page-about .team-table {
  width: 100%;
  margin-bottom: 22px;
}

.page-about .team-table th[scope="row"] {
  color: var(--chalk);
  font-weight: 500;
  white-space: nowrap;
}

.page-about .team-aside .note + .note {
  margin-top: 16px;
}

/* ---------- 地区长文 ---------- */
.page-about .region-prose p {
  max-width: 64ch;
}

.page-about .region-prose p + p {
  margin-top: 18px;
}

/* ---------- 边界收尾 ---------- */
.page-about .boundary-grid {
  margin-top: 24px;
}

.page-about .boundary-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 2px solid var(--steel);
}

.page-about .boundary-item {
  position: relative;
  padding: 14px 0 14px 30px;
  border-bottom: 1px solid var(--about-line);
  font-size: .9375rem;
  line-height: 1.8;
  color: var(--chalk);
}

.page-about .boundary-item::before {
  content: "×";
  position: absolute;
  left: 0;
  top: 13px;
  font-family: var(--font-mono);
  font-size: 1rem;
  color: var(--amber);
}

.page-about .boundary-panel {
  margin-top: 4px;
}

.page-about .boundary-panel .panel__foot .btn {
  display: inline-block;
}

/* ---------- 响应式 ---------- */
@media (min-width: 768px) {
  .page-about .about-masthead {
    padding-top: calc(var(--header-h) + 52px);
    padding-bottom: 60px;
  }

  .page-about .masthead-grid {
    grid-template-columns: 7fr 4fr;
    gap: 40px;
    align-items: start;
    margin-top: 30px;
  }

  .page-about .chapter {
    padding: 72px 0 78px;
  }

  .page-about .coverage-row {
    grid-template-columns: minmax(140px, 1fr) auto;
    align-items: baseline;
    gap: 6px 20px;
  }

  .page-about .coverage-row__note {
    grid-column: 2;
    text-align: right;
  }

  .page-about .flow-list {
    grid-template-columns: repeat(2, 1fr);
    gap: 18px;
  }

  .page-about .timeline {
    grid-template-columns: repeat(2, 1fr);
    gap: 0 30px;
  }

  .page-about .timeline__node:nth-child(odd) {
    border-left-color: transparent;
  }

  .page-about .timeline__node:nth-child(odd)::before {
    display: none;
  }
}

@media (min-width: 1024px) {
  .page-about .masthead-grid {
    grid-template-columns: 8fr 4fr;
    gap: 56px;
  }

  .page-about .about-h1 {
    font-size: clamp(3rem, 5.2vw, 3.9rem);
  }

  .page-about .flow-list {
    grid-template-columns: repeat(4, 1fr);
  }

  .page-about .timeline {
    grid-template-columns: repeat(5, 1fr);
    gap: 0 22px;
    padding-top: 12px;
  }

  .page-about .timeline__node {
    padding: 22px 8px 8px 0;
    border-left: 0;
    border-top: 2px solid var(--about-tick);
  }

  .page-about .timeline__node:nth-child(odd) {
    border-top-color: var(--about-tick);
  }

  .page-about .timeline__node::before {
    left: 0;
    top: -8px;
  }

  .page-about .timeline__node:nth-child(odd)::before {
    display: block;
  }

  .page-about .timeline__node:hover::before,
  .page-about .timeline__node:focus-within::before {
    background: var(--cyan);
  }

  .page-about .timeline__node:hover .timeline__desc,
  .page-about .timeline__node:focus-within .timeline__desc {
    color: var(--chalk);
  }

  .page-about .timeline__desc {
    font-size: .8125rem;
    line-height: 1.8;
  }
}

@media (min-width: 1440px) {
  .page-about .flow-list {
    gap: 22px;
  }

  .page-about .timeline {
    gap: 0 30px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .origin-col,
  .page-about .flow-step,
  .page-about .about-jump a,
  .page-about .chapter__index {
    transition: none;
  }

  .page-about .origin-col:hover,
  .page-about .flow-step:hover {
    transform: none;
  }
}