.page-about {
  --about-rail: 132px;
  --about-gap: clamp(1.5rem, 4vw, 3.25rem);
  overflow-x: clip;
}

.page-about .about-hero {
  padding-block: clamp(1.5rem, 3.5vw, 2.5rem) clamp(2rem, 5vw, 4rem);
  border-bottom: 1px solid var(--line-gold-soft);
}

.page-about .hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--about-gap);
  margin-top: clamp(1.25rem, 3vw, 2.25rem);
}

.page-about .hero-copy h1 {
  margin: 0.9rem 0 0;
}

.page-about .hero-copy .lede {
  margin: 1.35rem 0 0;
  max-width: 34ch;
  color: var(--graphite-600);
}

.page-about .hero-facts {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(1.6rem, 3vw, 2.4rem) 0 0;
  padding: 0;
  background: var(--line-gold-soft);
  border-top: 1px solid var(--line-gold);
}

.page-about .hero-facts > div {
  background: var(--ivory-050);
  padding: 0.9rem 0.75rem 1rem;
  min-width: 0;
}

.page-about .hero-facts dt {
  font-size: var(--fs-12);
  letter-spacing: 0.12em;
  color: var(--graphite-600);
  margin-bottom: 0.4rem;
}

.page-about .hero-facts dd {
  margin: 0;
  font-family: var(--font-display);
  font-size: var(--fs-24);
  color: var(--ink-900);
  line-height: 1.1;
}

.page-about .hero-facts dd .mono {
  font-size: 1.15em;
  color: var(--gold-500);
}

.page-about .hero-figure {
  margin: 0;
  position: relative;
}

.page-about .hero-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  border: 1px solid var(--line-gold);
}

.page-about .hero-figure figcaption,
.page-about .team-figure figcaption,
.page-about .closing-figure figcaption {
  margin-top: 0.65rem;
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--graphite-600);
  line-height: 1.6;
}

.page-about .chronicle-section {
  padding-block: clamp(2.25rem, 5.5vw, 4.5rem);
  background: var(--ivory-100);
}

.page-about .chronicle {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.5rem, 3vw, 2rem);
}

.page-about .chron-rail {
  border-top: 1px solid var(--line-gold);
  padding-top: 0.85rem;
}

.page-about .rail-head {
  margin: 0 0 0.7rem;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.18em;
  color: var(--graphite-600);
}

.page-about .chron-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1rem;
}

.page-about .chron-list a {
  display: inline-flex;
  align-items: baseline;
  gap: 0.5rem;
  padding: 0.15rem 0;
  font-size: var(--fs-13);
  color: var(--graphite-600);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.page-about .chron-list a:hover,
.page-about .chron-list a:focus-visible {
  color: var(--ink-900);
  border-color: var(--gold-500);
}

.page-about .chron-list .mono {
  font-size: var(--fs-12);
  color: var(--gold-500);
}

.page-about .chron-body {
  min-width: 0;
}

.page-about .chron-entry {
  padding-block: clamp(1.6rem, 3.5vw, 2.8rem);
  border-top: 1px solid var(--line-gold-soft);
}

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

.page-about .entry-index {
  margin: 0 0 0.75rem;
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  color: var(--gold-500);
}

.page-about .chron-entry h2 {
  margin: 0 0 1rem;
}

.page-about .chron-entry > p {
  margin: 0 0 1rem;
  max-width: 38ch;
  font-size: var(--fs-17);
  line-height: 1.75;
  color: var(--graphite-600);
}

.page-about .chron-entry > p:last-child {
  margin-bottom: 0;
}

.page-about .chron-entry strong {
  color: var(--ink-900);
  font-weight: 600;
}

/* 四条工作线 */
.page-about .lanes {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: clamp(1.5rem, 3vw, 2.25rem) 0 0;
  background: var(--line-gold-soft);
  border-block: 1px solid var(--line-gold);
}

.page-about .lane {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  padding: 1.35rem 1.05rem 1.1rem;
  background: var(--ivory-050);
  outline: none;
  --lane-accent: var(--gold-500);
}

.page-about .lane::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  background: var(--lane-accent);
}

.page-about .lane--proof { --lane-accent: var(--jade-500); }
.page-about .lane--service { --lane-accent: var(--cinnabar-600); }
.page-about .lane--ops { --lane-accent: var(--gold-300); }

.page-about .lane:focus-visible {
  box-shadow: inset 0 0 0 1px var(--gold-500);
}

.page-about .lane-num {
  margin: 0;
  font-size: var(--fs-12);
  color: var(--lane-accent);
  letter-spacing: 0.1em;
}

.page-about .lane-name {
  margin: 0;
  font-family: var(--font-display);
  font-size: var(--fs-24);
  font-weight: 400;
  letter-spacing: 0.02em;
  color: var(--ink-900);
  line-height: 1.25;
}

.page-about .lane-size {
  margin: 0;
  font-size: var(--fs-13);
  color: var(--graphite-600);
}

.page-about .lane-size .mono {
  font-size: 1.35em;
  color: var(--ink-900);
}

.page-about .lane-core {
  margin: 0.25rem 0 0;
  font-size: var(--fs-15);
  line-height: 1.7;
  color: var(--ink-900);
}

.page-about .lane-more {
  display: grid;
  grid-template-rows: 1fr;
  margin-top: 0.35rem;
}

.page-about .lane-more > div {
  overflow: hidden;
}

.page-about .lane-more p {
  margin: 0 0 0.45rem;
  font-size: var(--fs-13);
  line-height: 1.7;
  color: var(--graphite-600);
}

.page-about .lane-more p:last-child {
  margin-bottom: 0;
}

.page-about .team-figure {
  margin: clamp(1.5rem, 3vw, 2.25rem) 0 0;
}

.page-about .team-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 14 / 9;
  object-fit: cover;
  border: 1px solid var(--line-gold-soft);
}

/* 三道确认 */
.page-about .stages {
  margin: clamp(1.5rem, 3vw, 2.25rem) 0 1.5rem;
  padding: clamp(1.15rem, 3vw, 1.9rem) clamp(1rem, 2.5vw, 1.75rem);
  border: 1px solid var(--line-gold);
  background: var(--ivory-050);
}

.page-about .stage-map {
  display: none;
  width: 100%;
  height: auto;
}

.page-about .stage-line {
  stroke: var(--line-gold);
  stroke-width: 1.5;
}

.page-about .stage-node {
  fill: var(--gold-500);
}

.page-about .stage-node--mid {
  fill: var(--gold-300);
}

.page-about .stage-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.25rem;
}

.page-about .stage-list li {
  border-left: 1px solid var(--line-gold);
  padding-left: 0.95rem;
}

.page-about .stage-num {
  margin: 0 0 0.35rem;
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  color: var(--gold-500);
}

.page-about .stage-list h3 {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  font-size: var(--fs-24);
  font-weight: 400;
  color: var(--ink-900);
  line-height: 1.3;
}

.page-about .stage-list p:last-child {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.75;
  color: var(--graphite-600);
}

/* 四档成长 */
.page-about .tiers {
  list-style: none;
  margin: clamp(1.5rem, 3vw, 2.25rem) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
}

.page-about .tier {
  padding: 1.1rem 1rem 1.05rem;
  border-top: 1px solid var(--line-gold-soft);
  border-left: 3px solid var(--gold-300);
  background: var(--ivory-050);
}

.page-about .tier:nth-child(2) { border-left-color: var(--gold-500); }
.page-about .tier:nth-child(3) { border-left-color: var(--jade-500); }
.page-about .tier:nth-child(4) { border-left-color: var(--cinnabar-600); }

.page-about .tier-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
}

.page-about .tier-name {
  margin: 0;
  font-family: var(--font-display);
  font-size: var(--fs-24);
  font-weight: 400;
  letter-spacing: 0.14em;
  color: var(--ink-900);
}

.page-about .tier-tag {
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  color: var(--graphite-600);
}

.page-about .tier-desc {
  margin: 0.6rem 0 0;
  font-size: var(--fs-15);
  line-height: 1.75;
  color: var(--graphite-600);
  max-width: 40ch;
}

/* 透明度报告切换 */
.page-about .report {
  position: relative;
  margin: clamp(1.5rem, 3vw, 2.25rem) 0 0;
  border: 1px solid var(--line-gold);
  background: var(--ivory-050);
}

.page-about .report-input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  clip-path: inset(50%);
  pointer-events: none;
}

.page-about .report-labels {
  display: flex;
  flex-wrap: wrap;
  gap: 1px;
  background: var(--line-gold-soft);
  border-bottom: 1px solid var(--line-gold-soft);
}

.page-about .report-labels label {
  flex: 1 1 auto;
  padding: 0.7rem 0.9rem;
  background: var(--ivory-050);
  font-size: var(--fs-13);
  letter-spacing: 0.06em;
  color: var(--graphite-600);
  cursor: pointer;
  text-align: center;
  transition: color 0.18s var(--ease), background-color 0.18s var(--ease);
}

.page-about .report-labels label:hover {
  color: var(--ink-900);
}

.page-about #report-tab-1:checked ~ .report-labels label[for="report-tab-1"],
.page-about #report-tab-2:checked ~ .report-labels label[for="report-tab-2"],
.page-about #report-tab-3:checked ~ .report-labels label[for="report-tab-3"] {
  color: var(--ink-900);
  background: var(--ivory-100);
  box-shadow: inset 0 -2px 0 var(--gold-500);
}

.page-about #report-tab-1:focus-visible ~ .report-labels label[for="report-tab-1"],
.page-about #report-tab-2:focus-visible ~ .report-labels label[for="report-tab-2"],
.page-about #report-tab-3:focus-visible ~ .report-labels label[for="report-tab-3"] {
  outline: 2px solid var(--gold-500);
  outline-offset: -2px;
}

.page-about .report-panel {
  display: none;
  padding: 1.05rem 1rem 1.15rem;
}

.page-about #report-tab-1:checked ~ .report-panels #report-panel-1,
.page-about #report-tab-2:checked ~ .report-panels #report-panel-2,
.page-about #report-tab-3:checked ~ .report-panels #report-panel-3 {
  display: block;
}

.page-about .report-panel p {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.75;
  color: var(--graphite-600);
  max-width: 40ch;
}

.page-about .report-panel a {
  color: var(--ink-900);
  text-decoration: none;
  border-bottom: 1px solid var(--gold-500);
}

.page-about .report-panel a:hover,
.page-about .report-panel a:focus-visible {
  color: var(--gold-500);
}

/* 结尾 */
.page-about .closing {
  padding-block: clamp(2.25rem, 5.5vw, 4.5rem);
  background: var(--green-900);
  color: var(--ivory-050);
}

.page-about .closing-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.5rem, 4vw, 3rem);
  align-items: end;
}

.page-about .eyebrow--light {
  color: var(--gold-300);
}

.page-about .closing-copy h2 {
  margin: 0.8rem 0 1rem;
  color: var(--ivory-050);
  max-width: 20ch;
}

.page-about .closing-copy p {
  margin: 0;
  max-width: 36ch;
  font-size: var(--fs-17);
  line-height: 1.75;
  color: var(--ivory-100);
}

.page-about .closing-links {
  display: grid;
  gap: 1px;
  background: var(--line-dark);
  border-top: 1px solid var(--line-dark);
  border-bottom: 1px solid var(--line-dark);
}

.page-about .closing-links a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.95rem 0.25rem;
  background: var(--green-900);
  color: var(--ivory-050);
  text-decoration: none;
  font-size: var(--fs-17);
  border-bottom: 1px solid var(--line-dark);
  transition: color 0.2s var(--ease), padding-left 0.2s var(--ease);
}

.page-about .closing-links a:last-child {
  border-bottom: 0;
}

.page-about .closing-links a .mono {
  color: var(--gold-500);
}

.page-about .closing-links a:hover,
.page-about .closing-links a:focus-visible {
  color: var(--gold-300);
  padding-left: 0.75rem;
}

.page-about .closing-figure {
  margin: clamp(2rem, 4vw, 3rem) 0 0;
}

.page-about .closing-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border: 1px solid var(--line-dark);
}

.page-about .closing-figure figcaption {
  color: var(--gold-300);
  opacity: 0.85;
}

/* 桌面端 */
@media (min-width: 820px) {
  .page-about .lanes {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .stage-map {
    display: block;
    margin-bottom: 1.25rem;
  }

  .page-about .stage-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: clamp(1rem, 2.5vw, 2rem);
  }

  .page-about .closing-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  }
}

@media (min-width: 960px) {
  .page-about .hero-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: end;
  }

  .page-about .hero-figure {
    align-self: end;
  }
}

@media (min-width: 1040px) {
  .page-about .chronicle {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(2rem, 4vw, 4rem);
  }

  .page-about .chron-rail {
    position: sticky;
    top: calc(var(--header-h) + 2rem);
    align-self: start;
    border-top: 0;
    padding-top: 0;
    border-left: 1px solid var(--line-gold);
    padding-left: 1.1rem;
  }

  .page-about .chron-list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 1.05rem;
  }

  .page-about .chron-entry {
    max-width: 74ch;
  }

  .page-about .chron-entry:nth-of-type(even) {
    margin-left: clamp(0px, 5%, 4rem);
  }

  .page-about .chron-entry:nth-of-type(3n) {
    margin-left: clamp(0px, 2.5%, 1.75rem);
  }

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

  .page-about .lane-more {
    grid-template-rows: 0fr;
    transition: grid-template-rows 0.32s var(--ease);
  }

  .page-about .lane:hover .lane-more,
  .page-about .lane:focus .lane-more,
  .page-about .lane:focus-within .lane-more {
    grid-template-rows: 1fr;
  }

  .page-about .tier:nth-child(2) {
    margin-left: 4%;
  }

  .page-about .tier:nth-child(3) {
    margin-left: 8%;
  }

  .page-about .tier:nth-child(4) {
    margin-left: 12%;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition-duration: 0.001ms !important;
    animation-duration: 0.001ms !important;
  }
}
<<<END>>>