.page-about {
  --about-indent: var(--space-6);
}

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

.page-about .about-row .grid {
  row-gap: var(--space-8);
}

/* ---------- 页头 ---------- */

.page-about .about-head {
  padding-block-start: calc(var(--space-8) + var(--space-6));
}

.page-about .breadcrumb {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

.page-about .breadcrumb a {
  color: var(--color-ink-soft);
  text-decoration: none;
  border-bottom: var(--border-thin) solid transparent;
  transition: color 180ms ease-out, border-color 180ms ease-out;
}

.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

.page-about .about-head__title {
  margin: var(--space-6) 0 var(--space-4);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xl);
  line-height: 1.24;
  letter-spacing: -0.02em;
  color: var(--color-ink);
  max-width: 22ch;
}

.page-about .about-head__lede {
  margin: 0;
  max-width: 52ch;
  font-size: var(--text-lg);
  line-height: 1.62;
  color: var(--color-ink-soft);
}

.page-about .about-head__facts {
  margin: var(--space-8) 0 0;
  display: grid;
  gap: var(--space-2);
  max-width: 52ch;
  list-style: none;
}

.page-about .about-fact {
  display: grid;
  grid-template-columns: 5.5em 1fr;
  gap: var(--space-2);
  align-items: baseline;
  font-size: var(--text-sm);
  line-height: 1.7;
}

.page-about .about-fact dt {
  color: var(--color-ink-muted);
}

.page-about .about-fact dd {
  margin: 0;
  color: var(--color-ink);
  overflow-wrap: anywhere;
}

/* ---------- 开篇图 ---------- */

.page-about .about-hero-wrap {
  margin-block-start: var(--space-8);
}

.page-about .about-hero {
  margin: 0;
}

.page-about .about-hero img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  background-color: var(--color-surface-deep);
}

/* ---------- 叙事行 ---------- */

.page-about .about-row {
  padding-block: var(--section-y);
}

.page-about .about-row--end {
  padding-block: var(--section-y) var(--section-y-lg);
}

.page-about .about-aside {
  align-self: start;
}

.page-about .about-aside__num {
  margin: 0 0 var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--text-xl);
  line-height: 1;
  letter-spacing: 0.04em;
  color: var(--color-primary);
}

.page-about .about-aside__title {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  line-height: 1.32;
  letter-spacing: -0.01em;
  color: var(--color-ink);
  max-width: 14ch;
}

.page-about .about-aside__note {
  margin: var(--space-4) 0 0;
  max-width: 26ch;
  font-size: var(--text-sm);
  line-height: 1.7;
  color: var(--color-ink-muted);
}

.page-about .about-anchors {
  margin: var(--space-8) 0 0;
  display: grid;
  gap: var(--space-4);
}

.page-about .about-anchor dt {
  margin: 0 0 var(--space-1);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
}

.page-about .about-anchor dd {
  margin: 0;
}

.page-about .about-anchor__n {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-2xl);
  line-height: 1;
  color: var(--color-primary);
  font-variant-numeric: tabular-nums;
}

.page-about .about-anchor__u {
  display: block;
  margin-block-start: var(--space-1);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.page-about .about-jump {
  display: inline-block;
  margin-block-start: var(--space-6);
  padding-block-end: 2px;
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  text-decoration: none;
  border-bottom: var(--border-thin) solid var(--color-line);
  transition: color 180ms ease-out, border-color 180ms ease-out;
}

.page-about .about-jump:hover,
.page-about .about-jump:focus-visible {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

/* ---------- 正文 ---------- */

.page-about .about-body > p {
  margin: 0 0 var(--space-4);
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink);
}

.page-about .about-body > p:last-child {
  margin-block-end: 0;
}

.page-about .about-body .mark {
  background-image: linear-gradient(
    transparent 64%,
    color-mix(in srgb, var(--color-accent) 26%, transparent) 64%
  );
  background-repeat: no-repeat;
  background-size: 100% 0.55em;
  background-position: 0 92%;
}

.page-about .about-inline-figure {
  margin: var(--space-8) 0 0;
}

.page-about .about-inline-figure img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  background-color: var(--color-surface-deep);
}

.page-about .about-inline-figure .figure__caption {
  margin-block-start: var(--space-3);
  font-size: var(--text-xs);
  line-height: 1.7;
  color: var(--color-ink-muted);
  max-width: var(--measure);
}

/* ---------- 里程碑刻度 ---------- */

.page-about .milestones {
  list-style: none;
  margin: 0;
  padding: 0;
  position: relative;
}

.page-about .milestones::before {
  content: "";
  position: absolute;
  left: 0;
  top: var(--space-2);
  bottom: var(--space-4);
  width: var(--border-thin);
  background-color: color-mix(in srgb, var(--color-primary) 34%, transparent);
}

.page-about .milestone {
  position: relative;
  padding-block-end: var(--space-8);
}

.page-about .milestone:last-child {
  padding-block-end: 0;
}

.page-about .milestone::before {
  content: "";
  position: absolute;
  top: 0.55em;
  left: 0;
  width: 9px;
  height: 9px;
  transform: translateX(-50%);
  background-color: var(--color-primary);
  transition: background-color 200ms ease-out;
}

.page-about .milestone:last-child::before {
  background-color: var(--color-accent);
}

.page-about .milestone:focus-visible {
  outline: var(--border-thin) solid var(--color-focus);
  outline-offset: var(--space-2);
}

.page-about .milestone__body {
  padding-inline-start: var(--about-indent);
}

.page-about .milestone__year {
  margin: 0 0 var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  color: var(--color-primary);
}

.page-about .milestone__title {
  margin: 0 0 var(--space-3);
  max-width: 20ch;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--color-ink);
}

.page-about .milestone__text {
  margin: 0;
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

.page-about .milestone__note {
  margin: 0;
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  max-width: var(--measure);
  font-size: var(--text-sm);
  line-height: 1.7;
  color: var(--color-ink-muted);
  transition: max-height 200ms ease-out, opacity 200ms ease-out, margin-top 200ms ease-out;
}

.page-about .milestone:hover .milestone__note,
.page-about .milestone:focus-within .milestone__note,
.page-about .milestone:focus .milestone__note {
  max-height: 8em;
  opacity: 1;
  margin-block-start: var(--space-3);
}

/* ---------- 现状表 ---------- */

.page-about .about-table-wrap {
  margin: var(--space-6) 0;
  overflow-x: auto;
}

.page-about .about-table {
  width: 100%;
  min-width: 560px;
  border-collapse: collapse;
  text-align: left;
  font-size: var(--text-sm);
}

.page-about .about-table caption {
  caption-side: top;
  text-align: left;
  padding-block-end: var(--space-3);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
}

.page-about .about-table th,
.page-about .about-table td {
  padding: var(--space-3) var(--space-2);
  border-bottom: var(--border-thin) solid var(--color-line);
  vertical-align: top;
  line-height: 1.7;
  font-weight: var(--weight-body);
  color: var(--color-ink-soft);
}

.page-about .about-table thead th {
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
  border-bottom-color: var(--color-primary);
}

.page-about .about-table tbody th {
  color: var(--color-ink);
}

.page-about .about-table tbody tr:nth-child(even) {
  background-color: var(--color-surface-deep);
}

/* ---------- 收尾 ---------- */

.page-about .about-outro {
  margin-block-start: var(--space-6);
}

/* ---------- 断点 ---------- */

@media (min-width: 700px) {
  .page-about .about-head__title {
    font-size: var(--text-2xl);
  }
}

@media (min-width: 900px) {
  .page-about .about-head__title {
    font-size: var(--text-3xl);
  }

  .page-about .about-row {
    padding-block: calc(var(--section-y) * 1.35);
  }

  .page-about .about-row--end {
    padding-block: calc(var(--section-y) * 1.35) var(--section-y-lg);
  }

  .page-about .about-aside {
    position: sticky;
    top: calc(var(--space-8) + var(--space-4));
  }

  .page-about .about-aside__num {
    font-size: var(--text-2xl);
  }

  .page-about .milestone:nth-child(even) .milestone__body {
    margin-inline-start: var(--space-8);
  }
}

@media (hover: none) {
  .page-about .milestone__note {
    max-height: none;
    opacity: 1;
    margin-block-start: var(--space-3);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-jump,
  .page-about .breadcrumb a,
  .page-about .milestone::before,
  .page-about .milestone__note {
    transition: none;
  }
}