.page-about {
  --about-rail: 168px;
  --about-line: rgba(55, 191, 174, .32);
  --about-text: rgba(244, 241, 232, .8);
  --about-dim: rgba(244, 241, 232, .62);
  background: var(--ink-900);
  color: var(--paper);
  overflow-x: hidden;
}

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

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding-top: clamp(24px, 5vw, 56px);
  background:
    radial-gradient(120% 90% at 88% 0%, rgba(55, 191, 174, .13), transparent 55%),
    radial-gradient(90% 70% at 0% 100%, rgba(216, 168, 78, .08), transparent 60%),
    linear-gradient(160deg, var(--ink-900) 0%, var(--ink-800) 58%, var(--ink-900) 100%);
  border-bottom: 1px solid var(--hair);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  right: 0;
  bottom: 0;
  width: min(56%, 560px);
  height: min(64%, 320px);
  background: linear-gradient(125deg, rgba(216, 168, 78, .14), transparent 70%);
  clip-path: polygon(100% 0, 100% 100%, 0 100%);
  pointer-events: none;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
  padding-bottom: clamp(30px, 5vw, 56px);
}

.page-about .breadcrumb {
  margin-bottom: clamp(18px, 3vw, 30px);
}

.page-about .about-crumb {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--mist);
}

.page-about .about-crumb li {
  display: inline-flex;
  align-items: center;
}

.page-about .about-crumb li + li::before {
  content: "/";
  margin: 0 10px;
  color: rgba(166, 182, 177, .45);
}

.page-about .about-crumb a {
  color: var(--mist);
  text-decoration: none;
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

.page-about .about-crumb a:hover {
  color: var(--gold);
  border-bottom-color: var(--gold);
}

.page-about .about-crumb [aria-current="page"] {
  color: var(--gold);
}

.page-about .about-hero__eyebrow {
  margin: 0 0 20px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .22em;
  color: var(--mist);
  position: relative;
  padding-left: 34px;
}

.page-about .about-hero__eyebrow::before {
  content: "";
  position: absolute;
  left: 0;
  top: .62em;
  width: 22px;
  height: 1px;
  background: var(--gold);
}

.page-about .about-hero__title {
  margin: 0 0 24px;
  font-family: var(--font-display);
  font-size: clamp(2.1rem, 7.4vw, 4.75rem);
  line-height: 1.12;
  letter-spacing: -.02em;
  font-weight: 400;
  color: var(--paper);
  max-width: 18ch;
}

.page-about .about-hero__cut {
  color: var(--gold);
  background: linear-gradient(96deg, var(--gold) 8%, var(--gold-soft) 92%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.page-about .about-hero__lede {
  margin: 0 0 30px;
  max-width: 62ch;
  font-size: clamp(1rem, 2.2vw, 1.125rem);
  line-height: 1.85;
  color: var(--about-text);
}

.page-about .about-hero__facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(148px, 1fr));
  gap: 1px;
  background: var(--hair-soft);
  border: 1px solid var(--hair-soft);
}

.page-about .about-hero__facts li {
  background: rgba(10, 46, 39, .78);
  padding: 15px 16px;
  display: flex;
  flex-direction: column;
  gap: 9px;
  transition: background-color .2s var(--ease);
}

.page-about .about-hero__facts li:hover {
  background: var(--glass);
}

.page-about .about-fact__k {
  font-size: 11px;
  letter-spacing: .18em;
  color: var(--mist);
}

.page-about .about-fact__v {
  font-family: var(--font-display);
  font-size: clamp(1.25rem, 3vw, 1.7rem);
  line-height: 1.1;
  color: var(--gold);
  letter-spacing: .02em;
}

.page-about .about-hero__media {
  position: relative;
  margin: 0;
  line-height: 0;
  clip-path: polygon(0 14%, 100% 0, 100% 100%, 0 100%);
  background: var(--ink-900);
}

.page-about .about-hero__media img {
  display: block;
  width: 100%;
  height: clamp(200px, 34vw, 420px);
  object-fit: cover;
  filter: saturate(.82) brightness(.72) contrast(1.06);
}

.page-about .about-hero__media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(180deg, rgba(6, 33, 28, .1) 30%, rgba(6, 33, 28, .92) 100%);
}

/* ---------- 布局骨架 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(26px, 5vw, 56px);
  padding-block: clamp(34px, 6vw, 84px);
}

/* ---------- 左侧章节索引 ---------- */
.page-about .about-rail {
  border-bottom: 1px solid var(--hair-soft);
  padding-bottom: 14px;
}

.page-about .toc-title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .2em;
  color: var(--mist);
}

.page-about .toc-list {
  list-style: none;
  margin: 0;
  padding: 0 0 6px;
  display: flex;
  gap: 10px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .toc-list li {
  flex: 0 0 auto;
}

.page-about .toc-link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 7px 12px;
  font-size: 13.5px;
  color: var(--mist);
  text-decoration: none;
  border: 1px solid var(--hair-soft);
  background: rgba(10, 46, 39, .5);
  white-space: nowrap;
  transition: color .2s var(--ease), border-color .2s var(--ease), background-color .2s var(--ease);
}

.page-about .toc-link .index {
  font-size: 10px;
  color: rgba(216, 168, 78, .6);
  transition: color .2s var(--ease);
}

.page-about .toc-link:hover,
.page-about .toc-link:focus-visible {
  color: var(--gold-soft);
  border-color: var(--hair);
}

.page-about .toc-link[aria-current] {
  color: var(--gold);
  border-color: var(--gold);
  background: var(--glass);
}

.page-about .toc-link[aria-current] .index {
  color: var(--gold);
}

/* ---------- 章节 ---------- */
.page-about .about-flow {
  min-width: 0;
}

.page-about .chapter {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  padding-block: clamp(28px, 4.5vw, 54px);
  border-top: 1px solid var(--hair-soft);
}

.page-about .chapter:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .chapter__meta {
  display: flex;
  align-items: baseline;
  gap: 14px;
}

.page-about .chapter__no {
  margin: 0;
  font-size: clamp(26px, 4vw, 40px);
  line-height: 1;
  letter-spacing: .06em;
}

.page-about .chapter__tag {
  margin: 0;
  font-size: 11px;
  letter-spacing: .26em;
  color: var(--mist);
}

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

.page-about .chapter__title {
  margin: 0 0 18px;
  font-family: var(--font-display);
  font-size: clamp(1.4rem, 3.4vw, 2.2rem);
  line-height: 1.3;
  letter-spacing: -.01em;
  font-weight: 400;
  color: var(--paper);
  display: flex;
  align-items: flex-start;
  gap: 12px;
}

.page-about .chapter__title::before {
  content: "";
  flex: 0 0 auto;
  width: 10px;
  height: 10px;
  margin-top: .5em;
  background: var(--gold);
  clip-path: polygon(0 0, 100% 0, 0 100%);
}

.page-about .prose {
  max-width: 72ch;
  margin: 0 0 18px;
  font-size: 16px;
  line-height: 1.86;
  color: var(--about-text);
}

.page-about .prose:last-child {
  margin-bottom: 0;
}

.page-about .chapter__aside {
  margin-top: 22px;
  padding: 16px 18px;
  border-left: 2px solid var(--ink-700);
  background: rgba(10, 46, 39, .55);
  font-size: 15px;
  color: var(--about-dim);
}

.page-about .link-line {
  color: var(--gold-soft);
  text-decoration: none;
  padding-bottom: 1px;
  border-bottom: 1px solid var(--hair);
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

.page-about .link-line:hover {
  color: var(--gold);
  border-bottom-color: var(--gold);
}

/* ---------- 原则引用块 ---------- */
.page-about .quote-list {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  gap: 20px;
}

.page-about .quote-list li {
  position: relative;
  padding-left: 18px;
  border-left: 2px solid var(--gold);
}

.page-about .quote-list strong {
  display: block;
  margin-bottom: 7px;
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 400;
  letter-spacing: .03em;
  color: var(--gold-soft);
}

.page-about .quote-list p {
  margin: 0;
  font-size: 15px;
  line-height: 1.82;
  color: var(--about-text);
  max-width: 66ch;
}

/* ---------- 边界清单 ---------- */
.page-about .line-list {
  margin: 22px 0 0;
  border-top: 1px solid var(--hair-soft);
}

.page-about .line-list__row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 6px;
  padding: 16px 12px 16px 0;
  border-bottom: 1px solid var(--hair-soft);
  transition: background-color .18s var(--ease);
}

.page-about .line-list__row:hover {
  background: var(--glass);
}

.page-about .line-list dt {
  margin: 0;
}

.page-about .line-list dt .index {
  font-size: 12px;
  color: var(--gold);
}

.page-about .line-list dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.82;
  color: var(--about-text);
}

/* ---------- 区域矩阵 ---------- */
.page-about .area-grid {
  list-style: none;
  margin: 24px 0 10px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 8px;
}

.page-about .area-grid__cell {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .1em;
  text-align: center;
  padding: 14px 6px;
  color: var(--gold-soft);
  background: var(--glass);
  border: 1px solid var(--hair-soft);
  transition: border-color .18s var(--ease), background-color .18s var(--ease), color .18s var(--ease);
}

.page-about .area-grid__cell:hover {
  border-color: var(--gold);
  background: var(--glass-strong);
  color: var(--gold);
}

.page-about .area-grid__cap {
  margin: 0 0 22px;
  font-size: 11px;
  color: var(--mist);
}

/* ---------- 团队 ---------- */
.page-about .team {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin-top: 24px;
}

.page-about .team__unit {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 20px;
  background: var(--ink-800);
  border: 1px solid var(--hair-soft);
  transition: border-color .18s var(--ease), transform .18s var(--ease), box-shadow .18s var(--ease);
}

.page-about .team__unit:hover {
  border-color: var(--gold);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lift);
}

.page-about .team__unit h3 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 400;
  letter-spacing: .03em;
  color: var(--gold-soft);
}

.page-about .team__unit p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--about-dim);
}

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

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(.78) brightness(.76) contrast(1.05);
  border: 1px solid var(--hair-soft);
}

.page-about .about-figure .img-frame__cap {
  display: block;
  margin-top: 10px;
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--mist);
}

.page-about .chapter--team .prose:last-of-type {
  margin-top: 22px;
}

/* ---------- 问答折叠 ---------- */
.page-about .qa {
  display: grid;
  gap: 10px;
  margin-top: 22px;
}

.page-about .qa__item {
  border: 1px solid var(--hair-soft);
  background: rgba(10, 46, 39, .62);
  transition: border-color .18s var(--ease), background-color .18s var(--ease);
}

.page-about .qa__item:hover {
  border-color: var(--hair);
}

.page-about .qa__item[open] {
  border-color: var(--gold);
  background: var(--glass);
}

.page-about .qa__q {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 16px 18px;
  cursor: pointer;
  list-style: none;
  font-size: 15px;
  line-height: 1.65;
  color: var(--paper);
  transition: color .18s var(--ease);
}

.page-about .qa__q::-webkit-details-marker {
  display: none;
}

.page-about .qa__q::after {
  content: "＋";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--gold);
}

.page-about .qa__item[open] .qa__q::after {
  content: "－";
}

.page-about .qa__q:hover {
  color: var(--gold-soft);
}

.page-about .qa__no {
  flex: 0 0 auto;
  font-size: 11px;
  color: var(--gold);
}

.page-about .qa__a {
  padding: 0 18px 18px;
  border-top: 1px solid var(--hair-soft);
}

.page-about .qa__a p {
  margin: 14px 0 0;
  max-width: 68ch;
  font-size: 14.5px;
  line-height: 1.86;
  color: var(--about-text);
}

/* ---------- 时间轴 ---------- */
.page-about .timeline-shell {
  position: relative;
  margin-top: 24px;
  padding: 6px 0;
  overflow: hidden;
}

.page-about .timeline-shell__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: .14;
  filter: saturate(.55) brightness(.68);
  pointer-events: none;
  -webkit-mask-image: linear-gradient(180deg, transparent, #000 18%, #000 82%, transparent);
  mask-image: linear-gradient(180deg, transparent, #000 18%, #000 82%, transparent);
}

.page-about .timeline {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 8px 0 8px 26px;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 18px;
  bottom: 18px;
  width: 1px;
  background: linear-gradient(180deg, var(--data), rgba(55, 191, 174, .12));
}

.page-about .timeline > li {
  position: relative;
  padding-bottom: 8px;
}

.page-about .timeline > li::before {
  content: "";
  position: absolute;
  left: -25px;
  top: 16px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--ink-900);
  border: 2px solid var(--gold);
  transition: background-color .2s var(--ease), box-shadow .2s var(--ease);
}

.page-about .timeline > li:hover::before {
  box-shadow: 0 0 0 4px rgba(216, 168, 78, .16);
}

.page-about .timeline__item {
  border-bottom: 1px solid var(--hair-soft);
}

.page-about .timeline__item[open] {
  background: var(--glass);
}

.page-about .timeline__item[open] ~ * {
  border-color: var(--hair);
}

.page-about .timeline__summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px;
  padding: 14px 14px 14px 0;
  cursor: pointer;
  list-style: none;
}

.page-about .timeline__summary::-webkit-details-marker {
  display: none;
}

.page-about .timeline__stamp {
  flex: 0 0 auto;
  min-width: 66px;
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--data);
}

.page-about .timeline__title {
  font-family: var(--font-display);
  font-size: clamp(1.0625rem, 2.3vw, 1.25rem);
  letter-spacing: .01em;
  color: var(--paper);
  transition: color .2s var(--ease);
}

.page-about .timeline__summary:hover .timeline__title {
  color: var(--gold-soft);
}

.page-about .timeline__body {
  padding: 0 0 14px;
}

.page-about .timeline__body p {
  margin: 0;
  max-width: 64ch;
  font-size: 14.5px;
  line-height: 1.86;
  color: var(--about-text);
}

.page-about .chapter--history .prose:last-child {
  margin-top: 22px;
}

/* ---------- 继续查阅 ---------- */
.page-about .about-next {
  margin-top: clamp(20px, 3vw, 34px);
  padding-top: clamp(28px, 4vw, 48px);
  border-top: 1px solid var(--hair);
}

.page-about .about-next__title {
  margin: 0 0 20px;
  font-family: var(--font-display);
  font-size: clamp(1.25rem, 2.6vw, 1.75rem);
  font-weight: 400;
  letter-spacing: .02em;
  color: var(--paper);
}

.page-about .about-next__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.page-about .about-next__card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 22px;
  background: var(--ink-800);
  border: 1px solid var(--hair-soft);
  text-decoration: none;
  color: var(--paper);
  transition: border-color .18s var(--ease), background-color .18s var(--ease), transform .18s var(--ease);
}

.page-about .about-next__card:hover,
.page-about .about-next__card:focus-visible {
  border-color: var(--gold);
  background: var(--glass);
  transform: translateY(-2px);
}

.page-about .about-next__card .index {
  font-size: 11px;
  letter-spacing: .2em;
  color: var(--mist);
}

.page-about .about-next__card strong {
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 400;
  line-height: 1.6;
  color: var(--gold-soft);
}

/* ---------- 平板及以上 ---------- */
@media (min-width: 640px) {
  .page-about .area-grid {
    grid-template-columns: repeat(6, minmax(0, 1fr));
    gap: 10px;
  }

  .page-about .line-list__row {
    grid-template-columns: 172px minmax(0, 1fr);
    gap: 22px;
    align-items: baseline;
    padding-right: 16px;
  }

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

  .page-about .team__unit--lead {
    grid-column: span 2;
    grid-row: span 2;
  }

  .page-about .team__unit--wide {
    grid-column: span 2;
  }

  .page-about .about-next__grid {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

  .page-about .about-next__card {
    grid-column: span 3;
  }

  .page-about .about-next__card:last-child {
    grid-column: span 6;
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 900px) {
  .page-about .chapter {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: clamp(20px, 3vw, 44px);
  }

  .page-about .chapter__meta {
    flex-direction: column;
    gap: 10px;
    position: sticky;
    top: calc(var(--header-h) + 40px);
    align-self: start;
  }
}

@media (min-width: 1024px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(32px, 4vw, 72px);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 28px);
    align-self: start;
    border-bottom: 0;
    border-left: 1px solid var(--hair);
    padding: 0 0 0 18px;
  }

  .page-about .toc-list {
    display: grid;
    gap: 8px;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .toc-list li {
    flex: none;
  }

  .page-about .toc-link {
    display: flex;
    padding: 6px 0;
    background: none;
    border: 0;
    border-bottom: 1px solid transparent;
  }

  .page-about .toc-link[aria-current] {
    background: none;
  }

  .page-about .toc-link:hover,
  .page-about .toc-link:focus-visible {
    border-bottom-color: var(--gold);
  }

  .page-about .toc-link[aria-current] {
    border-bottom-color: var(--gold);
  }

  .page-about .chapter {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .team__unit:hover,
  .page-about .about-next__card:hover {
    transform: none;
  }
}