.page-about {
  padding-top: var(--header-h);
  background: var(--ink-800);
  color: var(--paper);
  overflow-x: clip;
}

/* ---------- 首屏 ---------- */
.page-about .about-head {
  position: relative;
  padding: 40px 0 56px;
  border-bottom: 1px solid var(--line-dark);
}

.page-about .about-head__lines {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: repeating-linear-gradient(90deg, var(--line-dark-soft) 0 1px, transparent 1px 96px);
}

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

.page-about .about-head__inner {
  display: grid;
  gap: 32px;
  margin-top: 22px;
}

.page-about .about-head h1 {
  margin: 0 0 18px;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(28px, 4.6vw, 50px);
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.page-about .about-head h1 em {
  font-style: normal;
  color: var(--amber);
}

.page-about .about-lede {
  margin: 0;
  max-width: 40em;
  font-size: 16px;
  line-height: 1.85;
  color: rgba(244, 238, 226, 0.82);
}

.page-about .about-facts {
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-dark-soft);
  border-top: 1px solid var(--line-dark);
  border-bottom: 1px solid var(--line-dark);
}

.page-about .about-facts__item {
  background: var(--ink-800);
  padding: 18px 22px;
}

.page-about .about-facts dt {
  margin: 0 0 10px;
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--sand);
}

.page-about .about-facts dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(22px, 3vw, 32px);
  font-variant-numeric: tabular-nums;
  color: var(--paper);
}

/* ---------- 通用区块 ---------- */
.page-about .about-block {
  padding: 64px 0;
  border-bottom: 1px solid var(--line-dark-soft);
}

.page-about .about-block--paper {
  background: var(--paper);
  color: var(--paper-ink);
  border-bottom-color: var(--line-light);
}

.page-about .about-block--paper .label {
  color: rgba(27, 22, 19, 0.6);
}

.page-about .about-block--paper .prose {
  color: rgba(27, 22, 19, 0.78);
}

.page-about .about-heading {
  display: grid;
  gap: 12px;
  margin-bottom: 36px;
}

.page-about .about-heading__idx {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--goji);
}

.page-about .about-heading h2 {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(23px, 3vw, 36px);
  line-height: 1.25;
  letter-spacing: -0.02em;
}

/* ---------- 起点 ---------- */
.page-about .origin {
  display: grid;
  gap: 26px;
}

.page-about .origin__body p + p {
  margin-top: 16px;
}

.page-about .origin__year {
  font-family: var(--font-mono);
  font-size: clamp(64px, 16vw, 132px);
  line-height: 0.86;
  letter-spacing: -0.05em;
  font-variant-numeric: tabular-nums;
  color: var(--ink-700);
}

/* ---------- 编年 ---------- */
.page-about .chron {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .chron__row {
  --fg: var(--paper);
  --fg-body: rgba(244, 238, 226, 0.8);
  --fg-muted: var(--haze);
  display: grid;
  gap: 16px;
  padding-block: 34px;
  border-top: 1px solid var(--line-dark-soft);
  color: var(--fg);
}

.page-about .chron__row--paper {
  --fg: var(--paper-ink);
  --fg-body: rgba(27, 22, 19, 0.78);
  --fg-muted: rgba(27, 22, 19, 0.64);
  background: var(--paper);
  margin-inline: calc(50% - 50vw);
  padding-inline: calc(50vw - 50%);
  border-top-color: transparent;
}

.page-about .chron__mark {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.page-about .chron__mark .label {
  color: var(--fg-muted);
}

.page-about .chron__to {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--fg-muted);
}

.page-about .year-mark {
  font-family: var(--font-mono);
  font-size: clamp(30px, 4.4vw, 44px);
  line-height: 1;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
  color: var(--sand);
  transition: color var(--ease);
}

.page-about .chron__row--paper .year-mark {
  color: var(--sand-deep);
}

.page-about .year-mark.is-visible {
  color: var(--amber);
}

.page-about .chron__row:hover .year-mark,
.page-about .chron__row:focus-within .year-mark {
  color: var(--amber);
}

.page-about .chron__body h3 {
  margin: 0 0 12px;
  font-family: var(--font-sans);
  font-weight: 900;
  font-size: clamp(19px, 2.2vw, 24px);
  line-height: 1.35;
  letter-spacing: -0.01em;
  color: var(--fg);
}

.page-about .chron__body .prose {
  margin: 0;
  color: var(--fg-body);
}

.page-about .stage__range {
  margin: 0;
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  font-size: 13px;
  line-height: 1.7;
  color: var(--fg-muted);
  transition: max-height var(--ease), opacity var(--ease), margin-top var(--ease);
}

.page-about .chron__row:hover .stage__range,
.page-about .chron__row:focus-within .stage__range {
  max-height: 90px;
  opacity: 1;
  margin-top: 14px;
}

.page-about .chron__row--media {
  display: block;
  padding-block: 0;
  border-top: none;
}

/* ---------- 图片 ---------- */
.page-about .media {
  margin: 0;
}

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

.page-about .media__img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  filter: saturate(0.72) contrast(1.06) brightness(0.92);
}

.page-about .media__caption {
  margin-top: 12px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--haze);
}

.page-about .about-block--paper .media__caption {
  color: rgba(27, 22, 19, 0.62);
}

/* ---------- 团队 ---------- */
.page-about .team {
  display: grid;
  gap: 36px;
}

.page-about .flow {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  border-top: 1px solid var(--line-light);
}

.page-about .flow__item {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 16px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line-light);
}

.page-about .flow__num {
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: 0.08em;
  color: var(--goji);
  padding-top: 3px;
}

.page-about .flow__title {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 700;
  color: var(--paper-ink);
}

.page-about .flow__item .prose {
  margin: 0;
  font-size: 15px;
}

/* ---------- 共建 ---------- */
.page-about .coop {
  display: grid;
  gap: 36px;
}

.page-about .coop__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 28px;
}

.page-about .coop__item {
  border-top: 2px solid var(--amber);
  padding-top: 16px;
}

.page-about .coop__item:nth-child(2) {
  border-top-color: var(--cyan);
}

.page-about .coop__item:nth-child(3) {
  border-top-color: var(--goji);
}

.page-about .coop__title {
  margin: 0 0 10px;
  font-size: 18px;
  font-weight: 700;
  color: var(--paper);
}

.page-about .coop__desc {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(244, 238, 226, 0.78);
}

.page-about .coop__aside {
  border: 1px solid var(--line-dark);
  background: rgba(46, 61, 78, 0.42);
  padding: 24px;
}

.page-about .coop__aside dl {
  margin: 0;
}

.page-about .coop__row {
  display: grid;
  gap: 5px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line-dark-soft);
}

.page-about .coop__row:last-child {
  border-bottom: none;
}

.page-about .coop__row dt {
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--sand);
}

.page-about .coop__row dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.6;
  color: var(--paper);
  overflow-wrap: anywhere;
}

.page-about .coop__note {
  margin: 16px 0 0;
  font-size: 13px;
  line-height: 1.75;
  color: var(--haze);
}

/* ---------- 里程碑 ---------- */
.page-about .mile {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line-dark-soft);
}

.page-about .mile__item {
  display: grid;
  gap: 6px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line-dark-soft);
  transition: background-color var(--ease);
}

.page-about .mile__item:hover {
  background: rgba(46, 61, 78, 0.3);
}

.page-about .mile__item:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
}

.page-about .mile__year {
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: 0.06em;
  font-variant-numeric: tabular-nums;
  color: var(--sand);
}

.page-about .mile__text {
  font-size: 16px;
  line-height: 1.75;
  color: var(--paper);
}

.page-about .mile__note {
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  font-size: 14px;
  line-height: 1.7;
  color: var(--haze);
  transition: max-height var(--ease), opacity var(--ease);
}

.page-about .mile__item:hover .mile__note,
.page-about .mile__item:focus .mile__note,
.page-about .mile__item:focus-within .mile__note {
  max-height: 90px;
  opacity: 1;
}

/* ---------- 尾部入口 ---------- */
.page-about .about-next {
  padding: 44px 0 60px;
  background: var(--ink-900);
}

.page-about .about-next__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-dark-soft);
}

.page-about .about-next__link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 22px;
  background: var(--ink-900);
  color: var(--paper);
  text-decoration: none;
  font-size: 15px;
  transition: color var(--ease), background-color var(--ease);
}

.page-about .about-next__link:hover {
  color: var(--amber);
  background: var(--ink-800);
}

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

/* ---------- 响应式 ---------- */
@media (min-width: 760px) {
  .page-about .about-facts {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .origin {
    grid-template-columns: minmax(0, 1fr) 260px;
    gap: 56px;
    align-items: start;
  }

  .page-about .origin__year {
    text-align: right;
  }

  .page-about .chron__row {
    grid-template-columns: 168px minmax(0, 1fr);
    gap: 46px;
    padding-block: 44px;
  }

  .page-about .coop__list {
    gap: 30px;
  }

  .page-about .mile__item {
    grid-template-columns: 190px minmax(0, 1fr);
    gap: 24px;
    align-items: baseline;
  }

  .page-about .mile__text,
  .page-about .mile__note {
    grid-column: 2;
  }
}

@media (min-width: 960px) {
  .page-about .about-head {
    padding: 56px 0 64px;
  }

  .page-about .about-head__inner {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: 56px;
    align-items: end;
  }

  .page-about .team {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    gap: 64px;
    align-items: start;
  }

  .page-about .coop {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr);
    gap: 64px;
    align-items: start;
  }

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

@media (max-width: 899px) {
  .page-about .chron__mark {
    flex-direction: row;
    align-items: baseline;
    gap: 12px;
    flex-wrap: wrap;
  }

  .page-about .chron__mark .label {
    flex-basis: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .year-mark,
  .page-about .stage__range,
  .page-about .mile__note,
  .page-about .about-next__link,
  .page-about .mile__item {
    transition: none;
  }
}