.page-about {
  --about-line: rgba(21, 24, 22, 0.14);
  --about-line-soft: rgba(21, 24, 22, 0.08);
  --about-rail-w: 220px;
  background-color: var(--paper);
  color: var(--body-ink);
  font-family: var(--font-body);
  -webkit-font-smoothing: antialiased;
}

.page-about .mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

/* ---------- 封面 ---------- */
.page-about .about-hero {
  position: relative;
  background-color: var(--ink-900);
  background-image:
    linear-gradient(to right, rgba(169, 199, 194, 0.07) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(169, 199, 194, 0.07) 1px, transparent 1px),
    radial-gradient(120% 90% at 88% -18%, rgba(39, 211, 194, 0.16), transparent 62%),
    radial-gradient(90% 80% at -6% 108%, rgba(201, 164, 92, 0.18), transparent 66%);
  background-size: 64px 64px, 64px 64px, auto, auto;
  color: var(--on-dark);
  padding: clamp(20px, 3.6vw, 36px) 0 clamp(40px, 6vw, 80px);
  border-bottom: 1px solid var(--hairline-gold);
}

.page-about .about-hero .breadcrumbs {
  font-size: 12.5px;
  letter-spacing: 0.06em;
}

.page-about .about-hero .crumb-link {
  color: var(--silver);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.25s var(--ease), border-color 0.25s var(--ease);
}

.page-about .about-hero .crumb-link:hover,
.page-about .about-hero .crumb-link:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .about-hero .crumb-sep {
  color: rgba(169, 199, 194, 0.5);
  margin: 0 8px;
}

.page-about .about-hero .crumb-now {
  color: var(--gold-200);
}

.page-about .about-hero-grid {
  display: grid;
  gap: clamp(28px, 4.5vw, 52px);
  margin-top: clamp(26px, 4.6vw, 58px);
}

.page-about .eyebrow {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.24em;
  color: var(--gold-500);
  text-transform: uppercase;
  margin: 0 0 14px;
}

.page-about .about-hero h1 {
  margin: 0;
  font-family: var(--font-display);
  color: var(--paper-soft);
  letter-spacing: 0.02em;
  line-height: 1.28;
  max-width: 18em;
}

.page-about .about-hero .lede {
  margin: clamp(16px, 2.4vw, 24px) 0 0;
  max-width: 46ch;
  font-size: clamp(15px, 1.35vw, 17px);
  line-height: 1.92;
  color: var(--on-dark);
}

.page-about .hero-line {
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding-left: 16px;
  border-left: 2px solid var(--gold-500);
  font-family: var(--font-display);
  font-size: clamp(15px, 1.6vw, 18px);
  letter-spacing: 0.05em;
  color: var(--gold-200);
}

.page-about .about-hero-index {
  border-top: 1px solid var(--hairline-gold);
  padding-top: 14px;
}

.page-about .index-title {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--gold-500);
  text-transform: uppercase;
}

.page-about .coord-list {
  margin: 14px 0 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .coord {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 14px;
  padding: 10px 0;
  border-bottom: 1px solid rgba(169, 199, 194, 0.18);
}

.page-about .coord:first-child {
  border-top: 1px solid rgba(169, 199, 194, 0.18);
}

.page-about .coord dt {
  font-size: 12.5px;
  letter-spacing: 0.05em;
  color: var(--on-dark-soft);
}

.page-about .coord dd {
  margin: 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 14.5px;
  letter-spacing: 0.04em;
  color: var(--gold-200);
}

/* ---------- 正文骨架 ---------- */
.page-about .about-body {
  padding: clamp(34px, 5.5vw, 76px) 0 clamp(46px, 7vw, 104px);
  background:
    linear-gradient(to bottom, rgba(169, 199, 194, 0.14), transparent 220px),
    var(--paper);
}

.page-about .about-layout {
  display: grid;
  gap: clamp(28px, 5vw, 60px);
}

/* ---------- 侧栏目录 ---------- */
.page-about .about-rail {
  border-top: 1px solid var(--about-line);
  padding-top: 14px;
}

.page-about .rail-label {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--mist);
  text-transform: uppercase;
}

.page-about .toc-list {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 4px 10px;
}

.page-about .toc-link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 6px 0;
  font-size: 13.5px;
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.25s var(--ease), border-color 0.25s var(--ease);
}

.page-about .toc-link .mono {
  font-size: 11px;
  color: var(--gold-500);
  letter-spacing: 0.08em;
}

.page-about .toc-link:hover,
.page-about .toc-link:focus-visible {
  color: var(--ink-900);
  border-bottom-color: var(--cyan);
}

.page-about .toc-link[aria-current="true"] {
  color: var(--ink-900);
  border-bottom-color: var(--gold-500);
  font-weight: 600;
}

/* ---------- 章节 ---------- */
.page-about .about-chapter {
  scroll-margin-top: 96px;
}

.page-about .about-chapter + .about-chapter {
  margin-top: clamp(46px, 7vw, 92px);
}

.page-about .chapter-head {
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: baseline;
  gap: 6px 16px;
  padding-top: 16px;
  border-top: 1px solid var(--about-line);
  margin-bottom: clamp(18px, 3vw, 28px);
}

.page-about .chapter-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--gold-500);
}

.page-about .chapter-head .title-md {
  margin: 0;
  font-family: var(--font-display);
  color: var(--ink-900);
  letter-spacing: 0.02em;
  line-height: 1.4;
}

.page-about .about-chapter > p {
  margin: 0 0 1.15em;
  font-size: clamp(15px, 1.15vw, 16px);
  line-height: 1.92;
  max-width: 62ch;
  color: var(--body-ink);
}

/* ---------- 指标条 ---------- */
.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
  margin: clamp(22px, 3.6vw, 34px) 0 0;
}

.page-about .fact {
  background: var(--paper-soft);
  padding: 16px 14px 18px;
  border-left: 2px solid var(--gold-500);
}

.page-about .fact-value {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(22px, 3vw, 30px);
  line-height: 1.1;
  color: var(--ink-900);
  letter-spacing: 0.02em;
}

.page-about .fact-value .unit {
  font-size: 0.5em;
  margin-left: 3px;
  color: var(--mist);
  letter-spacing: 0.04em;
}

.page-about .fact-label {
  display: block;
  margin-top: 9px;
  font-size: 12px;
  letter-spacing: 0.07em;
  color: var(--mist);
}

/* ---------- 引句 ---------- */
.page-about .about-quote {
  margin: clamp(24px, 4vw, 38px) 0 0;
  padding: 4px 0 4px 20px;
  border-left: 3px solid var(--gold-500);
}

.page-about .about-quote p {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(17px, 2vw, 23px);
  line-height: 1.72;
  color: var(--ink-900);
  max-width: 34ch;
}

.page-about .quote-src {
  display: block;
  margin-top: 10px;
  font-family: var(--font-mono);
  font-style: normal;
  font-size: 11.5px;
  letter-spacing: 0.12em;
  color: var(--mist);
}

/* ---------- 三层解释 ---------- */
.page-about .layer-list {
  list-style: none;
  margin: clamp(20px, 3.4vw, 30px) 0 clamp(22px, 3.6vw, 32px);
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
}

.page-about .layer {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 2px 16px;
  padding: 16px 18px 18px;
  background: var(--paper-soft);
  transition: background 0.25s var(--ease);
}

.page-about .layer:hover {
  background: #F8F5EC;
}

.page-about .layer-num {
  grid-row: span 2;
  padding-top: 4px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--cyan);
}

.page-about .layer h3 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 17px;
  letter-spacing: 0.03em;
  color: var(--ink-900);
}

.page-about .layer p {
  margin: 5px 0 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--body-ink);
  max-width: 54ch;
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: clamp(20px, 3.4vw, 30px) 0;
}

.page-about .img-frame {
  overflow: hidden;
  border: 1px solid var(--about-line);
  background: #E4E0D4;
}

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

.page-about .img-frame.ratio-4x3 img,
.page-about .img-frame.about-ratio-team img,
.page-about .img-frame.ratio-1x1 img {
  height: 100%;
  object-fit: cover;
}

.page-about .about-ratio-team {
  aspect-ratio: 3 / 2;
}

.page-about .about-figure--square {
  margin-top: 0;
}

.page-about .img-cap {
  margin: 10px 0 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.7;
  letter-spacing: 0.03em;
  color: var(--mist);
}

/* ---------- 版本对照 ---------- */
.page-about .compare {
  display: grid;
  gap: 1px;
  background: var(--hairline-strong);
  border: 1px solid var(--hairline-strong);
  margin: clamp(20px, 3.4vw, 30px) 0 clamp(18px, 3vw, 26px);
}

.page-about .compare-col {
  padding: 16px 18px 20px;
  background: var(--paper-soft);
}

.page-about .compare-col--old {
  background: rgba(232, 216, 176, 0.42);
}

.page-about .compare-col--new {
  background: var(--paper-soft);
  box-shadow: inset 3px 0 0 var(--gold-500);
}

.page-about .compare-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  padding-bottom: 10px;
  margin-bottom: 12px;
  border-bottom: 1px solid var(--about-line-soft);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--mist);
}

.page-about .compare-col p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.9;
  color: var(--body-ink);
}

.page-about .diff {
  background: rgba(182, 64, 46, 0.12);
  color: var(--cinnabar);
  font-style: normal;
  padding: 1px 3px;
  border-bottom: 1px solid rgba(182, 64, 46, 0.55);
}

/* ---------- 团队折叠 ---------- */
.page-about .fold-group {
  margin-top: clamp(18px, 3vw, 26px);
  border-bottom: 1px solid var(--about-line);
}

.page-about .fold {
  border-top: 1px solid var(--about-line);
  transition: border-color 0.25s var(--ease);
}

.page-about .fold:hover,
.page-about .fold[open] {
  border-top-color: var(--gold-500);
}

.page-about .fold-summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 15px 0;
  font-family: var(--font-display);
  font-size: 16px;
  letter-spacing: 0.02em;
  color: var(--ink-900);
}

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

.page-about .fold-summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--gold-500);
  transition: color 0.25s var(--ease);
}

.page-about .fold[open] .fold-summary::after {
  content: "–";
  color: var(--cyan);
}

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

.page-about .fold-body {
  padding: 0 0 18px;
}

.page-about .fold-body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.88;
  color: var(--body-ink);
  max-width: 58ch;
}

/* ---------- 时间轴 ---------- */
.page-about .timeline {
  list-style: none;
  display: flex;
  gap: 0;
  margin: clamp(22px, 3.6vw, 34px) 0 clamp(18px, 3vw, 26px);
  padding: 0 0 14px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  border-top: 1px solid var(--hairline-strong);
}

.page-about .timeline-node {
  position: relative;
  flex: 0 0 auto;
  width: min(230px, 74vw);
  padding: 26px 22px 6px 0;
  scroll-snap-align: start;
}

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

.page-about .timeline-node::after {
  content: "";
  position: absolute;
  top: -5px;
  left: 0;
  width: 9px;
  height: 9px;
  background: var(--gold-500);
}

.page-about .timeline-node--now::after {
  background: var(--cyan);
  box-shadow: 0 0 0 4px rgba(39, 211, 194, 0.18);
}

.page-about .timeline-ver {
  display: block;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--mist);
  transition: color 0.25s var(--ease);
}

.page-about .timeline-node--now .timeline-ver {
  color: var(--cyan);
}

.page-about .timeline-node h3 {
  margin: 8px 0 6px;
  font-family: var(--font-display);
  font-size: 16px;
  letter-spacing: 0.03em;
  color: var(--ink-900);
}

.page-about .timeline-node p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.82;
  color: var(--body-ink);
}

.page-about .timeline-node:hover .timeline-ver,
.page-about .timeline-node:focus-within .timeline-ver {
  color: var(--gold-500);
}

/* ---------- 合作 ---------- */
.page-about .about-partner-visual {
  display: grid;
  gap: clamp(20px, 3.4vw, 32px);
}

.page-about .about-partner-text > p {
  margin: 0 0 1.1em;
  font-size: clamp(15px, 1.15vw, 16px);
  line-height: 1.92;
  max-width: 60ch;
  color: var(--body-ink);
}

.page-about .chip-group {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 clamp(18px, 2.8vw, 24px);
}

.page-about .chip {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  padding: 7px 12px;
  border: 1px solid var(--hairline-strong);
  background: transparent;
  color: var(--ink-700);
  transition: background 0.25s var(--ease), color 0.25s var(--ease), border-color 0.25s var(--ease);
}

.page-about .chip[data-active="true"] {
  background: var(--ink-900);
  border-color: var(--ink-900);
  color: var(--gold-200);
}

.page-about .chip:hover {
  border-color: var(--cyan);
  color: var(--cyan);
}

.page-about .chip[data-active="true"]:hover {
  color: var(--paper-soft);
}

/* ---------- 结尾路线 ---------- */
.page-about .about-outro {
  margin-top: clamp(48px, 7vw, 92px);
  padding-top: clamp(20px, 3vw, 30px);
  border-top: 3px double var(--about-line);
}

.page-about .about-outro .title-md {
  margin: 0 0 12px;
  font-family: var(--font-display);
  color: var(--ink-900);
  letter-spacing: 0.02em;
}

.page-about .about-outro > p {
  margin: 0 0 clamp(20px, 3.2vw, 28px);
  font-size: 15px;
  line-height: 1.9;
  max-width: 58ch;
  color: var(--body-ink);
}

.page-about .route-grid {
  display: grid;
  gap: 1px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
}

.page-about .route-card {
  display: block;
  padding: 20px 18px 22px;
  background: var(--paper-soft);
  color: var(--ink-900);
  text-decoration: none;
  transition: background 0.28s var(--ease), color 0.28s var(--ease);
}

.page-about .route-kicker {
  display: block;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.22em;
  color: var(--gold-500);
  text-transform: uppercase;
}

.page-about .route-card h3 {
  margin: 9px 0 6px;
  font-family: var(--font-display);
  font-size: 17px;
  letter-spacing: 0.02em;
}

.page-about .route-card p {
  margin: 0;
  font-size: 13px;
  line-height: 1.75;
  color: var(--mist);
  transition: color 0.28s var(--ease);
}

.page-about .route-card:hover,
.page-about .route-card:focus-visible {
  background: var(--ink-900);
  color: var(--paper-soft);
}

.page-about .route-card:hover p,
.page-about .route-card:focus-visible p {
  color: var(--on-dark-soft);
}

.page-about .route-card:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: -4px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 760px) {
  .page-about .compare {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-partner-visual {
    grid-template-columns: minmax(0, 240px) minmax(0, 1fr);
    align-items: start;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.55fr) minmax(250px, 0.75fr);
    align-items: end;
  }
}

@media (min-width: 1024px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    align-items: start;
    gap: clamp(40px, 4.6vw, 76px);
  }

  .page-about .about-rail {
    position: sticky;
    top: 96px;
  }

  .page-about .toc-list {
    display: block;
  }

  .page-about .toc-link {
    display: flex;
    padding: 9px 0 9px 12px;
    border-bottom: none;
    border-left: 2px solid transparent;
  }

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

  .page-about .toc-link[aria-current="true"] {
    border-left-color: var(--gold-500);
    border-bottom-color: transparent;
  }

  .page-about .about-partner-visual {
    grid-template-columns: minmax(0, 280px) minmax(0, 1fr);
    gap: clamp(28px, 3.4vw, 44px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}
<<<END>>>