.page-about {
  --about-block-y: clamp(48px, 8vw, 96px);
  --about-node: var(--clay);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  background:
    radial-gradient(120% 90% at 82% 8%, rgba(24, 107, 74, .55) 0%, rgba(11, 27, 43, 0) 62%),
    var(--night);
  color: var(--paper);
  padding: clamp(104px, 14vw, 172px) 0 clamp(52px, 7vw, 92px);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: repeating-linear-gradient(
    90deg,
    var(--line-light) 0 1px,
    transparent 1px 64px
  );
  opacity: .5;
  pointer-events: none;
}

.page-about .about-hero__crumb {
  position: relative;
  z-index: 1;
  margin-bottom: clamp(28px, 5vw, 56px);
  color: var(--on-dark);
}

.page-about .about-hero__crumb a {
  color: var(--on-dark);
  text-decoration: none;
}

.page-about .about-hero__crumb a:hover,
.page-about .about-hero__crumb a:focus-visible {
  color: var(--signal);
  text-decoration: underline;
}

.page-about .about-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(28px, 5vw, 56px);
  align-items: end;
}

.page-about .about-hero__lead .eyebrow {
  color: var(--signal);
}

.page-about .about-hero h1 {
  margin: 14px 0 20px;
  font-size: var(--fs-display);
  font-weight: 900;
  line-height: 1.04;
  letter-spacing: -0.02em;
  color: var(--white);
  max-width: 15ch;
}

.page-about .about-hero__lede {
  max-width: 56ch;
  margin: 0;
  font-size: var(--fs-body);
  line-height: 1.75;
  color: var(--on-dark);
}

.page-about .about-hero__panel {
  background: var(--paper);
  color: var(--slate);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-card);
  box-shadow: 8px 8px 0 rgba(11, 27, 43, .45);
  padding: 22px 22px 18px;
}

.page-about .about-hero__panel-label {
  margin: 0 0 14px;
  font-family: var(--font-narrow);
  font-size: 12px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--clay);
}

.page-about .about-hero__facts {
  margin: 0;
  display: grid;
  gap: 0;
}

.page-about .about-fact {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px dashed var(--line);
}

.page-about .about-fact:last-child {
  border-bottom: 0;
}

.page-about .about-fact dt {
  font-size: 13px;
  color: var(--slate);
  opacity: .82;
}

.page-about .about-fact dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--graphite);
  white-space: nowrap;
}

/* ---------- 通用区块 ---------- */
.page-about .about-block {
  padding: var(--about-block-y) 0;
}

.page-about .about-h2 {
  margin: 12px 0 18px;
  font-size: var(--fs-h2);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--graphite);
  max-width: 24ch;
}

.page-about .eyebrow--dark {
  color: var(--clay);
}

.page-about .prose,
.page-about .dual__main p {
  font-size: var(--fs-body);
  line-height: 1.75;
  color: var(--slate);
  max-width: 62ch;
}

.page-about .dual__main p + p {
  margin-top: 1.1em;
}

.page-about .about-note {
  margin-top: 1.4em;
  padding-left: 16px;
  border-left: 3px solid var(--signal);
  font-size: 15px;
  color: var(--slate);
}

.page-about .dual__main a {
  color: var(--grass);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .dual__main a:hover,
.page-about .dual__main a:focus-visible {
  color: var(--signal);
}

/* ---------- 双线分栏 ---------- */
.page-about .dual {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(28px, 4vw, 48px);
}

.page-about .dual__side {
  order: -1;
}

/* ---------- 年份轨 ---------- */
.page-about .year-rail {
  list-style: none;
  margin: 0;
  padding: 4px 0 0 22px;
  border-left: 1px solid var(--line-strong);
}

.page-about .year-node {
  position: relative;
  padding-bottom: 26px;
}

.page-about .year-node:last-child {
  padding-bottom: 0;
}

.page-about .year-node::before {
  content: "";
  position: absolute;
  left: -28px;
  top: 6px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--paper);
  border: 2px solid var(--about-node);
}

.page-about .year-node__year {
  display: block;
  font-size: 20px;
  font-weight: 700;
  color: var(--clay);
  letter-spacing: .02em;
}

.page-about .year-node__text {
  display: block;
  margin-top: 4px;
  font-size: 14px;
  line-height: 1.65;
  color: var(--slate);
}

/* ---------- 横幅图 ---------- */
.page-about .about-banner {
  margin: 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .img-frame {
  position: relative;
  background: var(--mist);
  overflow: hidden;
}

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

.page-about .img-frame--wide img {
  aspect-ratio: 16 / 9;
}

.page-about .img-frame--tall img {
  aspect-ratio: 4 / 3;
  object-position: center;
}

.page-about .img-frame__caption {
  display: block;
  padding: 12px var(--gutter);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--slate);
  background: var(--paper);
  border-top: 1px solid var(--line);
}

/* ---------- 章节色带编号点亮 ---------- */
.page-about .chapter-band .chapter-band__num {
  color: var(--mist);
  transition: color var(--dur) var(--ease);
}

.page-about .chapter-band.is-visible .chapter-band__num {
  color: var(--signal);
}

/* ---------- 四条主线 ---------- */
.page-about .lanes {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 18px;
}

.page-about .lane {
  position: relative;
  display: grid;
  grid-template-columns: 46px 1fr;
  gap: 16px;
  align-items: start;
  padding: 22px 22px 22px 16px;
  background: var(--white);
  border: 1px solid var(--line);
  border-left: 4px solid var(--grass);
  border-radius: var(--radius-card);
  box-shadow: 5px 5px 0 rgba(58, 65, 73, .12);
}

.page-about .lane--offset {
  border-left-color: var(--clay);
}

.page-about .lane__no {
  font-family: var(--font-narrow);
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  color: var(--mist);
  letter-spacing: -0.02em;
}

.page-about .lane__title {
  margin: 0 0 6px;
  font-size: var(--fs-h3);
  font-weight: 700;
  color: var(--graphite);
}

.page-about .lane__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--slate);
}

.page-about .lanes__foot {
  margin: 26px 0 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--slate);
}

.page-about .lanes__foot a {
  color: var(--grass);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .lanes__foot a:hover,
.page-about .lanes__foot a:focus-visible {
  color: var(--signal);
}

/* ---------- 团队 ---------- */
.page-about .about-block--team {
  background: var(--paper);
}

.page-about .dual--media .dual__media {
  margin: 0;
  order: 0;
}

.page-about .mini-metrics {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 14px;
  margin-top: 28px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.page-about .mini-metrics .metric {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .mini-metrics .metric__value {
  font-size: 30px;
  font-weight: 700;
  color: var(--grass);
  line-height: 1;
}

.page-about .mini-metrics .metric__label {
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--slate);
}

/* ---------- 协作网络 ---------- */
.page-about .about-block--network {
  background: var(--white);
}

.page-about .dual__side--net {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.page-about .about-net {
  width: 100%;
  height: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  background: var(--paper);
}

.page-about .about-net__lines line {
  stroke: var(--moss);
  opacity: .55;
}

.page-about .about-net__hubs circle {
  fill: var(--clay);
}

.page-about .about-net__hubs .about-net__core {
  fill: var(--signal);
}

.page-about .about-net__spokes circle {
  fill: var(--white);
  stroke: var(--grass);
  stroke-width: 2;
  transition: fill var(--dur) var(--ease), r var(--dur) var(--ease);
}

.page-about .about-net__spokes circle:hover {
  fill: var(--signal);
}

.page-about .about-net__labels text {
  font-family: var(--font-sans);
  font-size: 13px;
  fill: var(--slate);
}

.page-about .net-facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 12px;
}

.page-about .net-facts li {
  padding: 12px 14px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  font-size: 13px;
  color: var(--slate);
}

.page-about .net-facts .num {
  display: block;
  font-size: 22px;
  font-weight: 700;
  color: var(--clay);
  margin-bottom: 2px;
}

.page-about .network-photo {
  margin: clamp(30px, 5vw, 52px) 0 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  overflow: hidden;
}

.page-about .network-photo img {
  aspect-ratio: 21 / 9;
  object-position: center 40%;
}

/* ---------- 时间线 ---------- */
.page-about .about-block--timeline {
  background: var(--paper);
}

.page-about .milestones {
  list-style: none;
  margin: 0;
  padding: 0 0 0 24px;
  border-left: 1px solid var(--line-strong);
}

.page-about .milestone {
  position: relative;
  display: grid;
  grid-template-columns: 1fr;
  gap: 6px;
  padding: 0 0 30px 0;
}

.page-about .milestone:last-child {
  padding-bottom: 0;
}

.page-about .milestone::before {
  content: "";
  position: absolute;
  left: -30px;
  top: 8px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--paper);
  border: 3px solid var(--clay);
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .milestone:hover::before {
  background: var(--signal);
  border-color: var(--signal);
}

.page-about .milestone__year {
  font-family: var(--font-mono);
  font-size: 24px;
  font-weight: 700;
  color: var(--graphite);
  letter-spacing: -0.01em;
  line-height: 1;
}

.page-about .milestone__body h3 {
  margin: 4px 0 6px;
  font-size: var(--fs-h3);
  font-weight: 700;
  color: var(--grass);
}

.page-about .milestone__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--slate);
  max-width: 58ch;
}

.page-about .timeline-foot {
  margin: 32px 0 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--slate);
}

.page-about .timeline-foot a {
  color: var(--grass);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .timeline-foot a:hover,
.page-about .timeline-foot a:focus-visible {
  color: var(--signal);
}

/* ---------- 为什么 ---------- */
.page-about .about-block--why {
  background: var(--night);
  color: var(--paper);
}

.page-about .about-block--why .about-block__lead {
  color: var(--on-dark);
}

.page-about .why-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
}

.page-about .why-card {
  position: relative;
  padding: 26px 22px 24px;
  background: rgba(245, 241, 232, .05);
  border: 1px solid var(--line-light);
  border-top: 3px solid var(--signal);
  border-radius: var(--radius-card);
}

.page-about .why-card__idx {
  display: block;
  font-family: var(--font-narrow);
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  color: var(--signal);
  margin-bottom: 14px;
}

.page-about .why-card h3 {
  margin: 0 0 10px;
  font-size: var(--fs-h3);
  font-weight: 700;
  color: var(--white);
}

.page-about .why-card p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--on-dark);
}

/* ---------- 使用场景 ---------- */
.page-about .about-block--scenes {
  background: var(--white);
}

.page-about .scenes {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
}

.page-about .scene {
  padding: 22px 20px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  box-shadow: 4px 4px 0 rgba(58, 65, 73, .1);
}

.page-about .scene h3 {
  margin: 12px 0 8px;
  font-size: 17px;
  font-weight: 700;
  color: var(--graphite);
}

.page-about .scene p {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--slate);
}

/* ---------- 结尾 ---------- */
.page-about .about-cta {
  background: linear-gradient(160deg, var(--grass) 0%, var(--night) 88%);
  color: var(--paper);
  padding: clamp(44px, 7vw, 82px) 0;
}

.page-about .about-cta__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 26px;
  align-items: center;
}

.page-about .about-cta h2 {
  margin: 0 0 12px;
  font-size: var(--fs-h2);
  font-weight: 800;
  line-height: 1.2;
  color: var(--white);
}

.page-about .about-cta p {
  margin: 0;
  max-width: 56ch;
  font-size: var(--fs-body);
  line-height: 1.75;
  color: var(--on-dark);
}

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

/* ---------- 响应式 ---------- */
@media (min-width: 760px) {
  .page-about .milestone {
    grid-template-columns: 130px 1fr;
    gap: 24px;
    align-items: start;
  }

  .page-about .milestone__year {
    font-size: 30px;
    padding-top: 2px;
  }

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

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.55fr) minmax(300px, 1fr);
    gap: clamp(32px, 5vw, 72px);
  }

  .page-about .dual {
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
    gap: clamp(32px, 5vw, 76px);
  }

  .page-about .dual__side {
    order: 0;
  }

  .page-about .dual--media {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.3fr);
  }

  .page-about .dual--media .dual__media {
    order: 0;
  }

  .page-about .lanes {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 22px;
  }

  .page-about .lane--offset:nth-child(even) {
    transform: translateY(22px);
  }

  .page-about .why-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 22px;
  }

  .page-about .about-cta__inner {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: 48px;
  }

  .page-about .about-cta__actions {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (min-width: 1180px) {
  .page-about .scenes {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

/* ---------- 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .chapter-band .chapter-band__num,
  .page-about .about-net__spokes circle,
  .page-about .milestone::before {
    transition: none;
  }
}