.page-about {
  background: var(--pitch);
  color: var(--text);
  padding-bottom: clamp(48px, 8vw, 96px);
  overflow-x: hidden;
}

.page-about .about-crumb {
  padding-top: 24px;
}

.page-about a:focus-visible,
.page-about [tabindex]:focus-visible {
  outline: 2px solid var(--electric);
  outline-offset: 3px;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding-top: clamp(20px, 3.5vw, 44px);
  padding-bottom: clamp(44px, 7vw, 88px);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
  align-items: end;
}

.page-about .about-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(32px, 5.2vw, 62px);
  line-height: 1.06;
  letter-spacing: -0.01em;
  color: var(--text);
  margin: 14px 0 20px;
}

.page-about .about-hero__lead {
  font-size: clamp(15px, 1.15vw, 17px);
  line-height: 1.85;
  color: var(--muted);
  max-width: 62ch;
  margin: 0;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.page-about .about-hero__figure {
  margin: 0;
}

@media (min-width: 960px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 56px;
  }
}

/* ---------- 关键数字带 ---------- */

.page-about .about-stats {
  background: var(--deep);
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}

.page-about .about-stats__grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px 10px;
  padding-top: 28px;
  padding-bottom: 28px;
}

.page-about .stat {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-left: 14px;
  border-left: 2px solid var(--flame);
}

.page-about .stat__value {
  font-family: var(--font-mono);
  font-size: clamp(24px, 3.2vw, 38px);
  line-height: 1;
  color: var(--text);
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
}

.page-about .stat__value small {
  font-size: 0.55em;
  color: var(--electric);
  margin-left: 2px;
}

.page-about .stat__label {
  font-size: 13px;
  color: var(--muted);
  letter-spacing: 0.02em;
}

@media (min-width: 720px) {
  .page-about .about-stats__grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 24px;
    padding-top: 34px;
    padding-bottom: 34px;
  }
}

/* ---------- 主体布局：左索引 + 右正文 ---------- */

.page-about .about-shell {
  max-width: var(--container);
  margin: 0 auto;
  padding: clamp(44px, 6.5vw, 84px) var(--gutter) 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 40px;
}

.page-about .about-side {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.page-about .about-side__block {
  border-top: 1px solid var(--rule);
  padding-top: 16px;
}

.page-about .toc__list {
  list-style: none;
  margin: 12px 0 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.page-about .toc__link {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 9px 10px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.5;
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: color 160ms var(--ease), border-color 160ms var(--ease), background-color 160ms var(--ease);
}

.page-about .toc__link:hover,
.page-about .toc__link:focus-visible {
  color: var(--text);
  border-left-color: var(--electric);
  background: rgba(46, 74, 85, 0.28);
}

.page-about .toc__link[aria-current="true"] {
  color: var(--text);
  border-left-color: var(--flame);
  background: rgba(255, 106, 26, 0.08);
}

.page-about .toc__num {
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--muted);
  flex: 0 0 auto;
}

.page-about .toc__link[aria-current="true"] .toc__num {
  color: var(--flame);
}

.page-about .about-side__milestones {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

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

.page-about .milestone__year {
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--electric);
  letter-spacing: 0.02em;
  flex: 0 0 58px;
  font-variant-numeric: tabular-nums;
}

.page-about .milestone__note {
  font-size: 13px;
  color: var(--muted);
  line-height: 1.5;
}

@media (min-width: 1024px) {
  .page-about .about-shell {
    grid-template-columns: minmax(200px, 3fr) minmax(0, 9fr);
    gap: 64px;
    align-items: start;
  }

  .page-about .about-side {
    position: sticky;
    top: calc(var(--masthead-offset) + 24px);
    align-self: start;
  }
}

/* ---------- 章节通用 ---------- */

.page-about .about-body {
  display: flex;
  flex-direction: column;
  gap: clamp(52px, 7.5vw, 100px);
  min-width: 0;
}

.page-about .chapter__head {
  border-bottom: 1px solid var(--rule);
  padding-bottom: 16px;
  margin-bottom: 26px;
}

.page-about .chapter__num {
  display: block;
  font-family: var(--font-display);
  font-size: clamp(50px, 7.4vw, 88px);
  font-weight: 700;
  line-height: 0.82;
  letter-spacing: -0.02em;
  color: var(--rule);
  margin-bottom: 10px;
  font-variant-numeric: tabular-nums;
}

.page-about .chapter__title {
  font-family: var(--font-display);
  font-size: clamp(22px, 2.4vw, 32px);
  line-height: 1.25;
  letter-spacing: -0.01em;
  color: var(--text);
  margin: 0;
}

.page-about .chapter p {
  font-size: 16px;
  line-height: 1.85;
  color: var(--text);
  margin: 0 0 18px;
  max-width: 68ch;
}

.page-about .chapter p.chapter__lead {
  font-size: clamp(17px, 1.4vw, 20px);
  line-height: 1.72;
  color: var(--text);
  padding-left: 16px;
  border-left: 3px solid var(--flame);
  margin: 0 0 26px;
  max-width: 60ch;
}

/* ---------- 数据链路 ---------- */

.page-about .pipeline {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  border-top: 1px solid var(--rule);
  margin: 6px 0 30px;
}

.page-about .pipeline__step {
  padding: 24px 0 22px;
  border-bottom: 1px solid var(--rule);
}

.page-about .pipeline__step-num {
  display: inline-block;
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--electric);
  border: 1px solid currentColor;
  padding: 3px 8px;
  margin-bottom: 14px;
}

.page-about .pipeline__step h3 {
  font-family: var(--font-display);
  font-size: 22px;
  line-height: 1.2;
  letter-spacing: 0.01em;
  color: var(--text);
  margin: 0 0 10px;
}

.page-about .pipeline__step p {
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--muted);
  margin: 0;
  max-width: 40ch;
}

.page-about .pipeline__figure {
  margin: 0;
}

@media (min-width: 820px) {
  .page-about .pipeline {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .pipeline__step {
    border-bottom: 0;
    border-left: 1px solid var(--rule);
    padding: 26px 24px 26px;
  }

  .page-about .pipeline__step:first-child {
    border-left: 0;
    padding-left: 0;
  }

  .page-about .pipeline__step:last-child {
    padding-right: 0;
  }
}

/* ---------- 团队 ---------- */

.page-about .team {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

.page-about .team__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.page-about .team__list li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 18px;
  padding-top: 16px;
  border-top: 1px solid var(--rule);
}

.page-about .team__count {
  grid-row: span 2;
  font-family: var(--font-mono);
  font-size: clamp(30px, 4vw, 44px);
  line-height: 1;
  color: var(--flame);
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
}

.page-about .team__count small {
  font-size: 0.5em;
  color: var(--electric);
}

.page-about .team__role {
  font-size: 15px;
  color: var(--text);
  align-self: end;
  letter-spacing: 0.02em;
}

.page-about .team__list p {
  grid-column: 2;
  font-size: 14px;
  line-height: 1.78;
  color: var(--muted);
  margin: 2px 0 0;
}

.page-about .team__figure {
  margin: 0;
}

@media (min-width: 900px) {
  .page-about .team {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 44px;
    align-items: start;
  }
}

/* ---------- 合作生态 ---------- */

.page-about .partners {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
  margin: 6px 0 22px;
}

.page-about .partners__card {
  position: relative;
  padding: 24px 22px;
  background: var(--deep);
  border: 1px solid var(--rule);
  transition: transform 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .partners__card::before {
  content: "";
  position: absolute;
  top: -1px;
  left: -1px;
  right: -1px;
  height: 2px;
  background: var(--electric);
}

.page-about .partners__card:nth-child(2)::before {
  background: var(--flame);
}

.page-about .partners__card:hover {
  transform: translateY(-4px);
  border-color: var(--electric);
}

.page-about .partners__type {
  display: block;
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--muted);
  margin-bottom: 12px;
}

.page-about .partners__card h3 {
  font-family: var(--font-display);
  font-size: 20px;
  line-height: 1.25;
  color: var(--text);
  margin: 0 0 10px;
}

.page-about .partners__card p {
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
  margin: 0;
}

.page-about .partners__note {
  font-size: 14px;
  line-height: 1.8;
  color: var(--text);
  border-left: 2px solid var(--amber);
  padding-left: 14px;
  margin: 0;
  max-width: 68ch;
}

@media (min-width: 760px) {
  .page-about .partners {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 22px;
  }
}

/* ---------- 时间线 ---------- */

.page-about .timeline {
  display: flex;
  gap: 0;
  overflow-x: auto;
  scroll-snap-type: x proximity;
  -webkit-overflow-scrolling: touch;
  padding: 4px 0 22px;
  margin: 0;
  scrollbar-width: thin;
  scrollbar-color: var(--rule) transparent;
}

.page-about .timeline__item {
  position: relative;
  flex: 0 0 76%;
  max-width: 300px;
  padding-right: 20px;
  scroll-snap-align: start;
  transition: transform 160ms var(--ease);
}

.page-about .timeline__item::after {
  content: "";
  position: absolute;
  top: 47px;
  left: 0;
  right: 20px;
  height: 1px;
  background: var(--rule-soft);
  pointer-events: none;
}

.page-about .timeline__year {
  display: block;
  height: 34px;
  font-family: var(--font-mono);
  font-size: 28px;
  line-height: 34px;
  color: var(--electric);
  letter-spacing: 0.02em;
  font-variant-numeric: tabular-nums;
}

.page-about .timeline__marker {
  position: relative;
  z-index: 1;
  display: block;
  width: 12px;
  height: 12px;
  margin: 8px 0 20px;
  background: var(--flame);
  box-shadow: 0 0 0 4px var(--pitch);
  transition: background-color 160ms var(--ease), transform 160ms var(--ease);
}

.page-about .timeline__item:hover .timeline__marker,
.page-about .timeline__item:focus-visible .timeline__marker {
  background: var(--flame);
  transform: scale(1.25);
}

.page-about .timeline__title {
  font-family: var(--font-display);
  font-size: 17px;
  line-height: 1.3;
  letter-spacing: 0.01em;
  color: var(--text);
  margin: 0 0 8px;
}

.page-about .timeline__text {
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--muted);
  margin: 0;
  max-width: 30ch;
}

.page-about .timeline__item:nth-child(2) .timeline__marker,
.page-about .timeline__item:nth-child(2) .timeline__year {
  color: var(--electric);
}

@media (min-width: 720px) {
  .page-about .timeline__item {
    flex: 0 0 262px;
    max-width: 262px;
  }
}

/* ---------- 三件事 ---------- */

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

.page-about .creed__item {
  padding: 22px 0 0;
  border-top: 2px solid var(--rule);
  margin-bottom: 22px;
}

.page-about .creed__item:nth-child(1) {
  border-top-color: var(--flame);
}

.page-about .creed__item:nth-child(2) {
  border-top-color: var(--electric);
}

.page-about .creed__item:nth-child(3) {
  border-top-color: var(--amber);
  margin-bottom: 0;
}

.page-about .creed__idx {
  display: block;
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--muted);
  margin-bottom: 12px;
}

.page-about .creed__item h3 {
  font-family: var(--font-display);
  font-size: 20px;
  line-height: 1.25;
  color: var(--text);
  margin: 0 0 10px;
}

.page-about .creed__item p {
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--muted);
  margin: 0;
  max-width: 40ch;
}

@media (min-width: 820px) {
  .page-about .creed {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 32px;
  }

  .page-about .creed__item {
    margin-bottom: 0;
  }
}

/* ---------- 结尾 ---------- */

.page-about .about-cta {
  margin-top: clamp(52px, 7.5vw, 96px);
  background: linear-gradient(135deg, rgba(16, 31, 58, 0.92), rgba(10, 38, 32, 0.92));
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}

.page-about .about-cta__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
  padding-top: clamp(38px, 5.5vw, 68px);
  padding-bottom: clamp(38px, 5.5vw, 68px);
}

.page-about .about-cta h2 {
  font-family: var(--font-display);
  font-size: clamp(23px, 3.1vw, 38px);
  line-height: 1.22;
  letter-spacing: -0.01em;
  color: var(--text);
  margin: 10px 0 12px;
}

.page-about .about-cta p {
  font-size: 15px;
  line-height: 1.82;
  color: var(--muted);
  margin: 0;
  max-width: 56ch;
}

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

@media (min-width: 880px) {
  .page-about .about-cta__inner {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: center;
    gap: 48px;
  }
}

/* ---------- 图片与动效兜底 ---------- */

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

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .page-about .partners__card:hover,
  .page-about .timeline__item:hover .timeline__marker,
  .page-about .timeline__item:focus-visible .timeline__marker {
    transform: none;
  }
}