.page-about {
  --about-rule: var(--hairline);
  --about-section-pad: clamp(48px, 7vw, 96px);
  --about-ink-soft: rgba(20, 33, 58, 0.72);
  --about-ink-line: rgba(20, 33, 58, 0.16);
  display: block;
  background: var(--ink-900);
  color: var(--text-hi);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.75;
  overflow-x: clip;
}

.page-about :focus-visible {
  outline: 2px solid var(--teal);
  outline-offset: 2px;
}

.page-about a {
  color: inherit;
  text-decoration: none;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding-top: clamp(32px, 5vw, 60px);
  padding-bottom: clamp(40px, 6vw, 76px);
  background:
    radial-gradient(120% 100% at 10% 0%, var(--teal-a08) 0%, transparent 58%),
    linear-gradient(180deg, var(--ink-950) 0%, var(--ink-900) 100%);
  border-bottom: 1px solid var(--about-rule);
}

.page-about .about-hero .breadcrumb {
  margin-bottom: clamp(26px, 5vw, 54px);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(26px, 4vw, 46px);
}

.page-about .about-hero h1 {
  margin: 14px 0 20px;
  font-size: clamp(32px, 6vw, 70px);
  font-weight: 300;
  line-height: 1.06;
  letter-spacing: -0.02em;
}

.page-about .about-hero .lede {
  margin: 0;
  max-width: 40ch;
  color: var(--text-mid);
}

.page-about .about-facts {
  border: 1px solid var(--about-rule);
  background: var(--ink-800);
  padding: 20px 20px 10px;
  box-shadow: var(--shadow-hover);
}

.page-about .about-facts__list {
  margin: 12px 0 0;
  padding: 0;
}

.page-about .about-facts__list > div {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 14px;
  justify-content: space-between;
  padding: 10px 0;
  border-top: 1px solid var(--about-rule);
}

.page-about .about-facts dt {
  color: var(--text-mid);
  font-size: 13px;
  letter-spacing: 0.06em;
}

.page-about .about-facts dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--text-hi);
}

/* ---------- 章节骨架 ---------- */

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

.page-about .about-head {
  display: grid;
  gap: 16px;
  margin-bottom: clamp(26px, 4vw, 46px);
}

.page-about .about-head h2 {
  margin: 12px 0 0;
  font-weight: 300;
  letter-spacing: -0.01em;
}

.page-about .tick-rule {
  min-height: 1px;
}

/* ---------- 01 沿革 ---------- */

.page-about .about-figure {
  margin: 0 0 clamp(28px, 4vw, 44px);
}

.page-about .figure__frame img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .timeline-rail {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(148px, 1fr);
  overflow-x: auto;
  border-top: 1px solid var(--about-rule);
  scrollbar-width: thin;
}

.page-about .timeline-rail > li {
  list-style: none;
}

.page-about .timeline-node {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 6px;
  height: 100%;
  padding: 22px 18px 20px 0;
  border-right: 1px solid var(--about-rule);
  color: var(--text-mid);
  transition: color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .timeline-rail > li:last-child .timeline-node {
  border-right: 0;
}

.page-about .timeline-node::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 1px;
  height: 12px;
  background: var(--about-rule);
}

.page-about .timeline-node:hover,
.page-about .timeline-node:focus-visible {
  color: var(--teal);
  background: var(--paper-a06);
}

.page-about .timeline-node__year {
  font-family: var(--font-display);
  font-size: 26px;
  font-weight: 300;
  letter-spacing: -0.02em;
  color: var(--text-hi);
  transition: color var(--dur) var(--ease);
}

.page-about .timeline-node:hover .timeline-node__year,
.page-about .timeline-node:focus-visible .timeline-node__year {
  color: var(--teal);
}

.page-about .timeline-node__tag {
  font-size: 12px;
  letter-spacing: 0.08em;
  line-height: 1.5;
}

.page-about .timeline-notes {
  display: grid;
  margin-top: clamp(22px, 4vw, 38px);
}

.page-about .timeline-note {
  padding: 18px 0;
  border-top: 1px solid var(--about-rule);
  scroll-margin-top: calc(var(--nav-h) + 24px);
}

.page-about .timeline-note:target {
  background: var(--teal-a08);
  box-shadow: inset 2px 0 0 0 var(--teal);
  padding-left: 16px;
}

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

.page-about .timeline-note h3 {
  margin: 8px 0 8px;
  font-size: 17px;
  font-weight: 500;
  color: var(--text-hi);
}

.page-about .timeline-note p:last-child {
  margin: 0;
  max-width: 40ch;
  color: var(--text-mid);
  font-size: 15.5px;
}

/* ---------- 02 栏目分工 ---------- */

.page-about .divisions-layout {
  display: grid;
  gap: clamp(28px, 4vw, 50px);
}

.page-about .divisions {
  min-width: 0;
}

.page-about .division-row {
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr);
  gap: 6px 16px;
  padding: 16px 0;
  border-top: 1px solid var(--about-rule);
  transition: background-color var(--dur) var(--ease);
}

.page-about .division-row:last-child {
  border-bottom: 1px solid var(--about-rule);
}

.page-about .division-row__no {
  padding-top: 4px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--text-mid);
}

.page-about .division-row__name {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 400;
  letter-spacing: -0.01em;
  color: var(--text-hi);
  justify-self: start;
}

.page-about .division-row__name:hover {
  color: var(--teal);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
}

.page-about .division-row__intent {
  grid-column: 2;
  margin: 0;
  max-width: 40ch;
  font-size: 15px;
  color: var(--text-mid);
}

.page-about .division-row__rate {
  grid-column: 2;
  margin: 2px 0 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--text-mid);
}

.page-about .division-row__detail {
  grid-column: 2;
  margin: 4px 0 0;
  max-height: 200px;
  overflow: hidden;
  font-size: 14px;
  color: var(--text-mid);
}

.page-about .division-row:hover {
  background: var(--paper-a06);
}

.page-about .divisions-aside {
  display: grid;
  gap: 20px;
  align-content: start;
}

.page-about .divisions-aside .figure {
  margin: 0;
}

.page-about .division-note {
  margin: 0;
  padding-left: 14px;
  border-left: 1px solid var(--violet-a50);
  color: var(--text-mid);
  font-size: 14.5px;
  max-width: 42ch;
}

/* ---------- 03 校对机制 ---------- */

.page-about .review-layout {
  display: grid;
  gap: clamp(28px, 4vw, 50px);
}

.page-about .review-intro {
  margin: 0;
  color: var(--text-mid);
}

.page-about .review-list {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
}

.page-about .review-list li {
  position: relative;
  padding: 14px 0 14px 34px;
  border-top: 1px solid var(--about-rule);
  color: var(--text-mid);
  font-size: 15.5px;
  max-width: 46ch;
}

.page-about .review-list li::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 22px;
  width: 12px;
  height: 7px;
  border-left: 1.5px solid var(--teal);
  border-bottom: 1.5px solid var(--teal);
  transform: rotate(-45deg);
}

.page-about .review-list strong {
  color: var(--text-hi);
  font-weight: 500;
}

.page-about .review-figure {
  margin: 0;
}

/* ---------- 04 / 05 纸面区块 ---------- */

.page-about .about-section--paper {
  background: var(--paper);
  color: var(--text-on-paper);
  border-bottom: 1px solid var(--about-rule);
}

.page-about .about-section--paper .exhibit-label,
.page-about .about-section--paper .index-label {
  color: rgba(20, 33, 58, 0.6);
}

.page-about .about-section--paper .exhibit-label__no {
  color: var(--teal-deep);
}

.page-about .about-section--paper .tick-rule {
  border-top-color: var(--about-ink-line);
}

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

.page-about .bounds-list > li {
  display: grid;
  gap: 6px;
  padding: 20px 0;
  border-top: 1px solid var(--about-ink-line);
}

.page-about .bounds-list > li:last-child {
  border-bottom: 1px solid var(--about-ink-line);
}

.page-about .bounds-list__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 500;
  letter-spacing: -0.01em;
}

.page-about .bounds-list__text {
  margin: 0;
  max-width: 44ch;
  font-size: 15.5px;
  color: var(--about-ink-soft);
}

.page-about .entity-grid {
  display: grid;
  gap: clamp(30px, 4vw, 52px);
}

.page-about .entity-block {
  min-width: 0;
}

.page-about .entity-table {
  width: 100%;
  margin-top: 12px;
  border-collapse: collapse;
  font-size: 15px;
}

.page-about .entity-table th,
.page-about .entity-table td {
  text-align: left;
  vertical-align: top;
  padding: 13px 0;
  border-top: 1px solid var(--about-ink-line);
}

.page-about .entity-table th {
  width: 40%;
  font-weight: 500;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: rgba(20, 33, 58, 0.6);
}

.page-about .entity-table td {
  color: var(--text-on-paper);
}

.page-about .about-section--paper .mono {
  font-family: var(--font-mono);
  font-size: 0.94em;
  padding: 1px 5px;
  background: rgba(20, 33, 58, 0.07);
  color: var(--text-on-paper);
  word-break: break-word;
}

.page-about .entity-caution {
  margin: 20px 0 0;
  padding-left: 14px;
  border-left: 2px solid var(--amber-deep);
  font-size: 14px;
  color: var(--about-ink-soft);
  max-width: 42ch;
}

.page-about .entity-caution a {
  color: var(--teal-deep);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

/* ---------- 收尾 ---------- */

.page-about .about-cta {
  padding: clamp(40px, 6vw, 72px) 0 clamp(56px, 8vw, 96px);
  background: var(--ink-950);
}

.page-about .about-cta__panel {
  display: grid;
  gap: 16px;
  padding: clamp(24px, 4vw, 42px);
  border: 1px solid var(--about-rule);
  border-left: 2px solid var(--teal);
  background: var(--ink-800);
  box-shadow: var(--shadow-hover);
}

.page-about .about-cta__panel h2 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(24px, 3.4vw, 38px);
  font-weight: 300;
  letter-spacing: -0.02em;
  line-height: 1.1;
}

.page-about .about-cta__text {
  margin: 0;
  max-width: 46ch;
  color: var(--text-mid);
  font-size: 15.5px;
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 4px;
}

/* ---------- 响应式 ---------- */

@media (min-width: 760px) {
  .page-about .bounds-list > li {
    grid-template-columns: 220px minmax(0, 1fr);
    gap: 24px;
    align-items: start;
  }

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

@media (min-width: 900px) {
  .page-about .about-head {
    grid-template-columns: minmax(0, 1fr) 200px;
    align-items: end;
  }

  .page-about .timeline-notes {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 48px;
  }

  .page-about .division-row {
    grid-template-columns: 48px 172px minmax(0, 1fr) 190px;
    gap: 0 20px;
    align-items: baseline;
  }

  .page-about .division-row__no {
    grid-column: 1;
  }

  .page-about .division-row__name {
    grid-column: 2;
  }

  .page-about .division-row__intent {
    grid-column: 3;
    margin: 0;
  }

  .page-about .division-row__rate {
    grid-column: 4;
    margin: 0;
    text-align: right;
  }

  .page-about .division-row__detail {
    grid-column: 2 / -1;
    max-height: 0;
    opacity: 0;
    margin: 0;
    transition:
      max-height var(--dur-slow) var(--ease),
      opacity var(--dur-slow) var(--ease),
      margin var(--dur-slow) var(--ease);
  }

  .page-about .division-row:hover .division-row__detail,
  .page-about .division-row:focus-within .division-row__detail {
    max-height: 140px;
    opacity: 1;
    margin-top: 10px;
  }

  .page-about .division-row:hover + .division-row,
  .page-about .division-row:focus-within + .division-row {
    border-top-color: transparent;
  }
}

@media (min-width: 940px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1fr) 300px;
    align-items: start;
  }

  .page-about .divisions-layout {
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .review-layout {
    grid-template-columns: minmax(0, 1fr) minmax(0, 380px);
    align-items: start;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .timeline-node,
  .page-about .division-row,
  .page-about .division-row__detail {
    transition: color var(--dur) var(--ease), background-color var(--dur) var(--ease);
  }

  .page-about .division-row__detail {
    max-height: 200px;
    opacity: 1;
  }
}