.page-about {
  --about-rail-w: 190px;
  --about-ease: cubic-bezier(0.22, 1, 0.36, 1);
  display: block;
  padding-bottom: 80px;
  background:
    radial-gradient(1100px 560px at 88% -6%, rgba(46, 74, 92, 0.34), transparent 62%),
    var(--ink);
  color: var(--paper);
  overflow-wrap: break-word;
}

.page-about .mono {
  font-family: var(--font-mono);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: 26px 0 0;
}

.page-about .about-hero-grid {
  display: grid;
  gap: 28px;
  margin-top: 28px;
}

.page-about .about-eyebrow {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--grid-soft);
}

.page-about h1 {
  margin: 14px 0 0;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(30px, 6.2vw, 58px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about h1 .signal-underline {
  background-image: linear-gradient(var(--signal), var(--signal));
  background-repeat: no-repeat;
  background-position: 0 94%;
  background-size: 100% 6px;
  padding-bottom: 2px;
}

.page-about .about-hero-lede {
  margin: 20px 0 0;
  font-size: 16px;
  line-height: 1.78;
  color: var(--dust);
  max-width: 62ch;
}

.page-about .about-figure {
  margin: 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--panel);
}

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

.page-about .about-figure figcaption {
  padding: 10px 16px 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--grid-soft);
  border-top: 1px solid var(--hairline);
}

.page-about .about-figure--hero {
  margin-top: 6px;
  box-shadow: var(--shadow-lift);
}

.page-about .about-figure--hero img {
  aspect-ratio: 16 / 9;
}

.page-about .about-stats {
  list-style: none;
  margin: 44px 0 0;
  padding: 26px 0 0;
  border-top: 1px solid var(--hairline);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px 16px;
}

.page-about .about-stats li {
  position: relative;
  padding-top: 12px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .about-stats li::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 22px;
  height: 2px;
  background: var(--signal);
}

.page-about .about-stat-value {
  font-size: clamp(20px, 2.6vw, 28px);
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-stat-label {
  font-size: 13px;
  color: var(--grid-soft);
}

/* ---------- 主体两栏 ---------- */
.page-about .about-body {
  display: grid;
  gap: 34px;
  margin-top: 56px;
}

.page-about .about-rail-title {
  margin: 0 0 12px;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--grid-soft);
}

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

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

.page-about .about-rail-link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 9px 14px;
  border-radius: 999px;
  background: var(--panel);
  border: 1px solid transparent;
  color: var(--dust);
  font-size: 13px;
  text-decoration: none;
  white-space: nowrap;
  transition: color 180ms var(--about-ease), background-color 180ms var(--about-ease),
    border-color 180ms var(--about-ease);
}

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

.page-about .about-rail-link:hover,
.page-about .about-rail-link:focus-visible {
  color: var(--paper);
  border-color: rgba(255, 106, 19, 0.5);
  background: var(--panel-soft);
}

/* ---------- 章节 ---------- */
.page-about .about-stage {
  scroll-margin-top: 100px;
}

.page-about .about-stage + .about-stage {
  margin-top: 60px;
  padding-top: 42px;
  border-top: 1px solid var(--hairline);
}

.page-about .about-stage-head {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-stage-num {
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--signal);
}

.page-about h2 {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(22px, 3.6vw, 34px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about p {
  margin: 18px 0 0;
  font-size: 16px;
  line-height: 1.78;
  color: rgba(242, 239, 231, 0.84);
  max-width: 68ch;
}

.page-about h3 {
  margin: 0;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .about-note {
  padding: 16px 20px;
  border-radius: var(--radius);
  background: rgba(18, 49, 42, 0.72);
  border-left: 4px solid var(--signal-soft);
  font-size: 15px;
  color: var(--dust);
}

/* ---------- 阶段时间线 ---------- */
.page-about .about-epochs {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
}

.page-about .about-epoch {
  position: relative;
  padding: 0 0 26px 26px;
  border-left: 1px solid var(--hairline-strong);
}

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

.page-about .about-epoch::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 6px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--grid);
  box-shadow: 0 0 0 3px var(--ink);
  transition: background-color 180ms var(--about-ease);
}

.page-about .about-epoch:hover::before {
  background: var(--signal);
}

.page-about .about-epoch-tag {
  display: block;
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--grid-soft);
}

.page-about .about-epoch h3 {
  margin-top: 6px;
}

.page-about .about-epoch p {
  margin-top: 8px;
  font-size: 15px;
  color: var(--dust);
}

.page-about .about-epochs + .about-figure {
  margin-top: 34px;
}

/* ---------- 归档流程 ---------- */
.page-about .about-split {
  display: grid;
  gap: 30px;
  margin-top: 4px;
}

.page-about .about-flow {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .about-flow-step {
  padding: 18px 20px;
  border-radius: var(--radius);
  background: var(--panel);
}

.page-about .about-flow-num {
  display: block;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--signal);
}

.page-about .about-flow-step h3 {
  margin-top: 8px;
}

.page-about .about-flow-step p {
  margin-top: 6px;
  font-size: 15px;
  color: var(--dust);
}

.page-about .about-figure--work img {
  aspect-ratio: 3 / 2;
}

/* ---------- 双层索引 ---------- */
.page-about .about-lens {
  margin: 28px 0 0;
  display: grid;
  gap: 0;
  border-top: 1px solid var(--hairline);
}

.page-about .about-lens-row {
  display: grid;
  gap: 6px;
  padding: 20px 0;
  border-bottom: 1px solid var(--hairline);
}

.page-about .about-lens-key {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--signal);
}

.page-about .about-lens-row p {
  margin: 0;
  font-size: 15px;
  color: var(--dust);
  max-width: 62ch;
}

.page-about .about-quote {
  margin: 30px 0 0;
  padding: 18px 22px;
  border-left: 4px solid var(--signal);
  border-radius: 0 var(--radius) var(--radius) 0;
  background: var(--panel);
}

.page-about .about-quote p {
  margin: 0;
  font-size: 16px;
  line-height: 1.72;
  color: var(--paper);
  max-width: 58ch;
}

/* ---------- 团队 ---------- */
.page-about .about-team {
  margin-top: 26px;
}

.page-about .about-team .tablist {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .about-team .tabpanel {
  padding-top: 20px;
}

.page-about .about-team .tabpanel p {
  margin-top: 0;
  max-width: 64ch;
}

/* ---------- 合作生态 ---------- */
.page-about .about-partners {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .about-partners li {
  padding: 20px 0;
  border-bottom: 1px solid var(--hairline);
}

.page-about .about-partners li:first-child {
  border-top: 1px solid var(--hairline);
}

.page-about .about-partner-name {
  display: block;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--signal-soft);
}

.page-about .about-partners p {
  margin-top: 8px;
  font-size: 15px;
  color: var(--dust);
  max-width: 64ch;
}

/* ---------- 收尾 ---------- */
.page-about .about-cta {
  margin-top: 64px;
  padding: 34px 26px 30px;
  border-radius: var(--radius-lg);
  background: linear-gradient(140deg, var(--panel), var(--ink-deep) 88%);
  border: 1px solid var(--hairline);
}

.page-about .about-cta h2 {
  font-size: clamp(20px, 3vw, 28px);
}

.page-about .about-cta p {
  margin-top: 14px;
  max-width: 64ch;
}

.page-about .about-cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 768px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 24px;
  }

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

  .page-about .about-lens-row {
    grid-template-columns: 120px minmax(0, 1fr);
    align-items: baseline;
    gap: 18px;
  }

  .page-about .about-cta {
    padding: 44px 40px 40px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-hero {
    padding-top: 34px;
  }

  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.18fr) minmax(0, 0.82fr);
    align-items: end;
    gap: 52px;
    margin-top: 34px;
  }

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

  .page-about .about-body {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: 60px;
    margin-top: 72px;
  }

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

  .page-about .about-rail-list {
    flex-direction: column;
    overflow: visible;
    gap: 0;
    padding: 0;
  }

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

  .page-about .about-rail-link {
    border-radius: 0;
    border: none;
    border-left: 1px solid var(--hairline);
    background: none;
    padding: 11px 0 11px 20px;
    white-space: normal;
    position: relative;
    line-height: 1.5;
  }

  .page-about .about-rail-link::before {
    content: "";
    position: absolute;
    left: -5px;
    top: 17px;
    width: 9px;
    height: 9px;
    border-radius: 50%;
    background: var(--grid);
    transition: background-color 180ms var(--about-ease), box-shadow 180ms var(--about-ease);
  }

  .page-about .about-rail-link:hover,
  .page-about .about-rail-link:focus-visible {
    background: none;
    border-color: var(--hairline);
    color: var(--paper);
  }

  .page-about .about-rail-link:hover::before,
  .page-about .about-rail-link:focus-visible::before {
    background: var(--signal);
    box-shadow: 0 0 0 5px rgba(255, 106, 19, 0.14);
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    align-items: start;
    gap: 44px;
  }

  .page-about .about-split-main > p:first-child {
    margin-top: 18px;
  }

  .page-about .about-figure--work {
    margin-top: 18px;
  }

  .page-about .about-partners {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0 32px;
    border-bottom: 1px solid var(--hairline);
  }

  .page-about .about-partners li {
    border-bottom: none;
    padding: 24px 0;
  }

  .page-about .about-partners li:first-child {
    border-top: none;
  }

  .page-about .about-partners li + li {
    border-left: 1px solid var(--hairline);
    padding-left: 28px;
  }
}

@media (min-width: 1440px) {
  .page-about .about-hero-grid {
    gap: 72px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail-link,
  .page-about .about-epoch::before,
  .page-about .about-rail-link::before {
    transition-duration: 120ms;
  }
}