.page-about {
  --about-sticky: 112px;
  background: var(--paper);
  color: var(--ink);
}

.page-about .crumb {
  padding: 14px 0 4px;
}

.page-about .section {
  padding: 52px 0;
}

.page-about .section-head {
  max-width: 760px;
  margin-bottom: 26px;
}

.page-about .section-kicker {
  color: var(--graphite);
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin: 0 0 4px;
}

.page-about .section-title {
  font-size: clamp(26px, 4.8vw, 40px);
  line-height: 1.18;
  letter-spacing: -0.02em;
  font-weight: 800;
  margin: 6px 0 0;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: 6px 0 4px;
}

.page-about .about-trace {
  display: block;
  width: 100%;
  height: 16px;
  color: var(--blue);
  opacity: 0.9;
  margin: 6px 0 22px;
}

.page-about .about-title {
  font-size: clamp(32px, 7.4vw, 62px);
  line-height: 1.1;
  letter-spacing: -0.025em;
  font-weight: 900;
  max-width: 900px;
  margin: 10px 0 18px;
}

.page-about .about-lede {
  font-size: 17px;
  line-height: 1.8;
  color: var(--graphite);
  max-width: 640px;
  margin: 0 0 24px;
}

.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 30px;
}

.page-about .about-band {
  margin: 0;
  background: var(--white);
  border: 3px solid var(--ink-dark);
  border-radius: var(--r-card);
  box-shadow: var(--sh-2);
  overflow: hidden;
}

.page-about .about-band img {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .about-band figcaption,
.page-about .about-map figcaption,
.page-about .about-cycle figcaption {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  line-height: 1.5;
  color: var(--graphite);
  padding: 10px 14px;
  border-top: 3px solid var(--ink-dark);
  background: var(--white);
}

/* ---------- 规模数字 ---------- */
.page-about .about-scale-copy p {
  font-size: 16px;
  line-height: 1.8;
  color: var(--graphite);
  max-width: 760px;
  margin: 0;
}

.page-about .about-scale-copy p + p {
  margin-top: 14px;
}

.page-about .about-stats {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .about-stat {
  background: var(--white);
  border: 3px solid var(--ink-dark);
  border-radius: var(--r-card);
  box-shadow: var(--sh-1);
  padding: 20px 18px;
  transition: transform var(--t-card) var(--ease), box-shadow var(--t-card) var(--ease);
}

.page-about .about-stat:hover,
.page-about .about-stat:focus-within,
.page-about .about-stat:focus {
  transform: translateY(-2px);
  box-shadow: var(--sh-2);
  outline: none;
}

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

.page-about .about-stat-num {
  display: block;
  font-size: clamp(46px, 12vw, 72px);
  font-weight: 900;
  line-height: 1;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
  color: var(--ink);
}

.page-about .about-stat-unit {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--moss);
}

.page-about .about-stat-note {
  margin: 12px 0 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--graphite);
}

@media (min-width: 768px) {
  .page-about .about-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 20px;
  }

  .page-about .about-stat-note {
    max-height: 0;
    margin-top: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height var(--t-card) var(--ease), opacity var(--t-card) var(--ease), margin var(--t-card) var(--ease);
  }

  .page-about .about-stat:hover .about-stat-note,
  .page-about .about-stat:focus .about-stat-note,
  .page-about .about-stat:focus-within .about-stat-note {
    max-height: 8em;
    margin-top: 12px;
    opacity: 1;
  }
}

/* ---------- 年份时间轴 ---------- */
.page-about .about-road-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
}

.page-about .about-rail {
  display: none;
}

.page-about .about-timeline {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-node {
  position: relative;
  padding: 0 0 34px 26px;
  border-left: 3px solid var(--line);
}

.page-about .about-node:last-child {
  border-left-color: transparent;
  padding-bottom: 0;
}

.page-about .about-node .timeline-node {
  position: absolute;
  left: -9px;
  top: 6px;
  width: 15px;
  height: 15px;
  border-radius: 50%;
  background: var(--white);
  border: 3px solid var(--blue);
}

.page-about .about-node--now .timeline-node {
  background: var(--lime);
  border-color: var(--ink-dark);
}

.page-about .about-node-year {
  display: inline-block;
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--blue);
}

.page-about .about-node h3 {
  font-size: 19px;
  font-weight: 700;
  line-height: 1.35;
  margin: 8px 0 8px;
}

.page-about .about-node p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--graphite);
  max-width: 62ch;
}

@media (min-width: 1024px) {
  .page-about .about-road-grid {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: 56px;
  }

  .page-about .about-rail {
    display: block;
    align-self: start;
    position: sticky;
    top: var(--about-sticky);
    padding-left: 18px;
    border-left: 3px solid var(--line);
  }

  .page-about .about-rail-year {
    position: relative;
    display: block;
    font-size: 15px;
    letter-spacing: 0.1em;
    color: var(--graphite);
    opacity: 0.55;
    transition: color var(--t-fast) var(--ease), opacity var(--t-fast) var(--ease);
  }

  .page-about .about-rail-year + .about-rail-year {
    margin-top: 26px;
  }

  .page-about .about-rail-year::before {
    content: "";
    position: absolute;
    left: -25px;
    top: 50%;
    transform: translateY(-50%);
    width: 9px;
    height: 9px;
    border-radius: 50%;
    background: var(--line);
  }

  .page-about .about-rail-year--now {
    color: var(--ink);
    opacity: 1;
  }

  .page-about .about-rail-year--now::before {
    width: 11px;
    height: 11px;
    left: -26px;
    background: var(--lime);
    border: 2px solid var(--ink-dark);
  }
}

/* ---------- 服务范围 ---------- */
.page-about .about-audience-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

.page-about .about-aud-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .about-aud {
  background: var(--white);
  border: 3px solid var(--ink-dark);
  border-radius: var(--r-sm);
  box-shadow: var(--sh-1);
  padding: 18px 18px 20px;
}

.page-about .about-aud-index {
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--moss);
}

.page-about .about-aud h3 {
  font-size: 18px;
  font-weight: 700;
  line-height: 1.4;
  margin: 8px 0 8px;
}

.page-about .about-aud p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--graphite);
}

.page-about .about-region {
  margin-top: 22px;
  padding: 18px 20px;
  background: var(--mist);
  border: 3px solid var(--ink-dark);
  border-radius: var(--r-card);
  box-shadow: var(--sh-blue);
}

.page-about .about-region p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--graphite);
}

.page-about .about-map,
.page-about .about-cycle {
  margin: 0;
  background: var(--white);
  border: 3px solid var(--ink-dark);
  border-radius: var(--r-card);
  box-shadow: var(--sh-1);
  overflow: hidden;
}

.page-about .about-map img,
.page-about .about-cycle img {
  display: block;
  width: 100%;
  height: auto;
}

@media (min-width: 900px) {
  .page-about .about-audience-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: 48px;
    align-items: start;
  }
}

/* ---------- 更新节奏 ---------- */
.page-about .about-rhythm-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

.page-about .about-rhythm-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 18px;
}

.page-about .about-rhythm-item {
  padding-bottom: 16px;
  border-bottom: 2px solid var(--line);
}

.page-about .about-rhythm-item:last-child {
  padding-bottom: 0;
  border-bottom: 0;
}

.page-about .about-rhythm-key {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--blue);
}

.page-about .about-rhythm-key::before {
  content: "";
  width: 8px;
  height: 8px;
  background: var(--lime);
  border: 2px solid var(--ink-dark);
}

.page-about .about-rhythm-item p {
  margin: 8px 0 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--graphite);
}

@media (min-width: 900px) {
  .page-about .about-rhythm-grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    gap: 48px;
    align-items: center;
  }
}

/* ---------- 深色能力带 ---------- */
.page-about .about-capability {
  background-color: var(--ink-dark);
  background-image: linear-gradient(rgba(255, 255, 255, 0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.06) 1px, transparent 1px);
  background-size: 48px 48px;
  color: var(--paper);
  padding: 52px 0;
  margin-top: 6px;
  border-top: 3px solid var(--ink-dark);
  border-bottom: 3px solid var(--ink-dark);
}

.page-about .about-capability .section-kicker {
  color: var(--lime);
}

.page-about .about-capability .section-title {
  color: var(--white);
}

.page-about .about-folds {
  display: grid;
  gap: 14px;
}

.page-about .about-fold {
  border: 2px solid rgba(255, 255, 255, 0.22);
  border-radius: var(--r-sm);
  background: rgba(255, 255, 255, 0.04);
  padding: 2px 16px;
}

.page-about .about-fold summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 15px 0;
  font-size: 16px;
  font-weight: 700;
  color: var(--white);
}

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

.page-about .about-fold summary::before {
  content: "▸";
  color: var(--lime);
  font-size: 14px;
  transition: transform var(--t-fast) var(--ease);
}

.page-about .about-fold[open] summary::before {
  transform: rotate(90deg);
}

.page-about .about-fold summary:focus-visible {
  outline: 3px solid var(--lime);
  outline-offset: 4px;
}

.page-about .about-fold p {
  margin: 0 0 16px;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(246, 248, 251, 0.84);
}

.page-about .about-fold .mono {
  color: var(--lime);
}

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

@media (min-width: 900px) {
  .page-about .about-folds {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }
}

/* ---------- 合作入口 ---------- */
.page-about .about-cta {
  padding-bottom: 64px;
}

.page-about .about-cta-bar {
  display: flex;
  flex-direction: column;
  gap: 16px;
  padding: 24px;
  background: var(--white);
  border: 3px solid var(--ink-dark);
  border-radius: var(--r-card);
  box-shadow: var(--sh-1);
  color: var(--ink);
  text-decoration: none;
  transition: transform var(--t-card) var(--ease), box-shadow var(--t-card) var(--ease), background-color var(--t-fast) var(--ease);
}

.page-about .about-cta-bar:hover {
  transform: translateY(-2px);
  box-shadow: var(--sh-2);
  background: var(--mist);
}

.page-about .about-cta-bar:focus-visible {
  outline: 3px solid var(--blue);
  outline-offset: 4px;
}

.page-about .about-cta-text {
  font-size: 16px;
  line-height: 1.7;
  color: var(--graphite);
  max-width: 56ch;
}

.page-about .about-cta-go {
  flex: 0 0 auto;
  align-self: flex-start;
  font-size: 14px;
  letter-spacing: 0.08em;
  color: var(--white);
  background: var(--blue);
  border: 3px solid var(--ink-dark);
  border-radius: var(--r-pill);
  padding: 10px 18px;
  box-shadow: var(--sh-1);
}

.page-about .about-links {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .about-links a {
  display: inline-block;
  font-size: 14px;
  padding: 8px 14px;
  background: var(--white);
  border: 2px solid var(--ink-dark);
  border-radius: var(--r-pill);
  color: var(--ink);
  text-decoration: none;
  transition: background-color var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}

.page-about .about-links a:hover {
  background: var(--blue);
  color: var(--white);
}

.page-about .about-links a:focus-visible {
  outline: 3px solid var(--blue);
  outline-offset: 3px;
}

@media (min-width: 768px) {
  .page-about .about-cta-bar {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: 32px;
    padding: 28px 32px;
  }

  .page-about .about-cta-go {
    align-self: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-stat,
  .page-about .about-cta-bar,
  .page-about .about-links a,
  .page-about .about-fold summary::before {
    transition: none;
  }

  .page-about .about-stat:hover,
  .page-about .about-cta-bar:hover {
    transform: none;
  }
}