.page-about {
  --ab-sticky-top: 7rem;
  --ab-scroll-offset: 96px;
  background: var(--ab-bg);
  color: var(--ab-ink);
  font-family: var(--font-body);
  line-height: 1.75;
  overflow-x: hidden;
}

.page-about .ab-story {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.25rem;
  align-items: start;
  padding: calc(32px + 1vw) 0 0;
}

.page-about .ab-story__rail {
  order: 2;
  display: grid;
  gap: 1.25rem;
  align-content: start;
  padding: 1.5rem;
  background: var(--ab-white);
  border: var(--border-navy);
  box-shadow: var(--shadow-hard);
}

.page-about .ab-story__content {
  order: 1;
  min-width: 0;
}

.page-about .ab-rail-brand {
  display: flex;
  align-items: center;
  gap: 0.875rem;
}

.page-about .ab-rail-brand__logo {
  display: inline-grid;
  place-items: center;
  flex: 0 0 auto;
  width: 48px;
  height: 48px;
  background: var(--ab-navy);
  color: var(--ab-gold);
  font-family: var(--font-head);
  font-size: 1.5rem;
  font-weight: 700;
  clip-path: polygon(0 0, 100% 0, 100% 72%, 80% 100%, 0 100%);
}

.page-about .ab-rail-brand__meta {
  display: flex;
  flex-direction: column;
  line-height: 1.3;
}

.page-about .ab-rail-brand__name {
  font-family: var(--font-head);
  font-size: 1.4rem;
  letter-spacing: 0.04em;
  color: var(--ab-navy);
}

.page-about .ab-rail-brand__slogan {
  font-size: 0.8rem;
  letter-spacing: 0.14em;
  color: var(--ab-gold);
}

.page-about .ab-toc {
  border-top: 2px solid var(--ab-cream);
  padding-top: 1.25rem;
}

.page-about .ab-toc__label {
  margin: 0 0 0.75rem;
  font-family: var(--font-head);
  font-size: 0.9rem;
  letter-spacing: 0.2em;
  color: var(--ab-navy);
}

.page-about .ab-toc__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.4rem;
}

.page-about .ab-toc__list a {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  padding: 0.55rem 0.75rem;
  color: var(--ab-ink);
  text-decoration: none;
  font-weight: 600;
  border-left: 3px solid transparent;
  transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}

.page-about .ab-toc__list a:hover,
.page-about .ab-toc__list a:focus-visible {
  background: var(--ab-bg);
  border-color: var(--ab-gold);
  color: var(--ab-navy);
}

.page-about .ab-toc__num {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--ab-gold);
}

.page-about .ab-toc__title {
  font-size: 0.95rem;
}

.page-about .ab-rail__cta {
  width: 100%;
  justify-content: center;
  text-align: center;
}

.page-about .ab-rail__note {
  margin: 0;
  font-size: 0.85rem;
  line-height: 1.6;
  color: var(--ab-blue);
}

.page-about .breadcrumbs {
  margin-bottom: 1.5rem;
}

.page-about .breadcrumbs a {
  color: var(--ab-navy);
  text-decoration: none;
}

.page-about .breadcrumbs a:hover {
  text-decoration: underline;
}

.page-about .ab-hero {
  position: relative;
  margin-bottom: 3.25rem;
  padding: 0.75rem 0 2.5rem;
  border-bottom: var(--border-navy);
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  left: 0;
  bottom: -3px;
  width: 34%;
  height: 3px;
  background: var(--ab-gold);
}

.page-about .ab-hero__title {
  margin: 0 0 1.25rem;
  font-family: var(--font-head);
  font-size: clamp(2rem, 7vw, 3.4rem);
  line-height: 1.08;
  letter-spacing: 0.02em;
  color: var(--ab-navy);
}

.page-about .ab-hero__lead {
  margin: 0 0 1.5rem;
  max-width: 64ch;
  font-size: 1.0625rem;
  color: var(--ab-blue);
  border-left: 5px solid var(--ab-gold);
  padding-left: 1.25rem;
}

.page-about .ab-hero__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-hero-stat {
  padding: 1rem 1.125rem;
  background: var(--ab-navy);
  color: var(--ab-white);
  box-shadow: var(--shadow-gold);
}

.page-about .ab-hero-stat dt {
  margin: 0;
  font-size: 1.5rem;
  line-height: 1.1;
  font-weight: 700;
  color: var(--ab-gold);
}

.page-about .ab-hero-stat dd {
  margin: 0.25rem 0 0;
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.82);
}

.page-about .ab-chapter {
  position: relative;
  scroll-margin-top: var(--ab-scroll-offset);
  padding: 2.25rem 0 3rem;
  border-top: 2px dashed rgba(10, 35, 66, 0.15);
}

.page-about .ab-chapter::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 6px;
  background: linear-gradient(135deg, var(--ab-navy) 0 58%, var(--ab-gold) 58% 100%);
}

.page-about .ab-chapter__head {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 2px solid var(--ab-cream);
}

.page-about .ab-chapter__num {
  display: inline-block;
  padding: 0.3rem 0.65rem;
  background: var(--ab-navy);
  color: var(--ab-gold);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
}

.page-about .ab-chapter__head h2 {
  margin: 0;
  font-family: var(--font-head);
  font-size: clamp(1.75rem, 3.4vw, 2.5rem);
  line-height: 1.1;
  color: var(--ab-navy);
}

.page-about .ab-chapter__body {
  display: grid;
  gap: 1.25rem;
}

.page-about .ab-chapter__body p {
  margin: 0;
  color: var(--ab-blue);
}

.page-about .ab-chapter__figure {
  margin: 0.25rem 0 0.5rem;
  border: var(--border-navy);
  background: var(--ab-navy);
  box-shadow: var(--shadow-gold);
  overflow: hidden;
}

.page-about .ab-chapter__figure--wide {
  margin-bottom: 1.5rem;
}

.page-about .ab-chapter__img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .ab-timeline {
  list-style: none;
  margin: 0.75rem 0 0;
  padding: 0;
  position: relative;
  display: grid;
  gap: 1.75rem;
}

.page-about .ab-timeline::before {
  content: "";
  position: absolute;
  left: 42px;
  top: 4px;
  bottom: 4px;
  width: 3px;
  background: var(--ab-navy);
}

.page-about .ab-timeline__item {
  position: relative;
  display: grid;
  grid-template-columns: 84px minmax(0, 1fr);
  gap: 1rem;
  align-items: start;
}

.page-about .ab-timeline__item:nth-child(1) {
  animation: ab-rise 0.5s 0.05s ease both;
}

.page-about .ab-timeline__item:nth-child(2) {
  animation: ab-rise 0.5s 0.1s ease both;
}

.page-about .ab-timeline__item:nth-child(3) {
  animation: ab-rise 0.5s 0.15s ease both;
}

.page-about .ab-timeline__item:nth-child(4) {
  animation: ab-rise 0.5s 0.2s ease both;
}

.page-about .ab-timeline__item:nth-child(5) {
  animation: ab-rise 0.5s 0.25s ease both;
}

.page-about .ab-timeline__item:nth-child(6) {
  animation: ab-rise 0.5s 0.3s ease both;
}

.page-about .ab-timeline__marker {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 0.4rem 0.3rem;
  background: var(--ab-navy);
  border: 2px solid var(--ab-gold);
  color: var(--ab-gold);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  line-height: 1.1;
  text-align: center;
  clip-path: polygon(0 0, calc(100% - 8px) 0, 100% 50%, calc(100% - 8px) 100%, 0 100%);
}

.page-about .ab-timeline__card {
  background: var(--ab-white);
  border: 2px solid var(--ab-navy);
  box-shadow: 4px 4px 0 rgba(10, 35, 66, 0.14);
  padding: 1rem 1.125rem;
}

.page-about .ab-timeline__card .tag {
  margin-bottom: 0.55rem;
}

.page-about .ab-timeline__card h3 {
  margin: 0 0 0.4rem;
  font-family: var(--font-head);
  font-size: 1.3rem;
  line-height: 1.15;
  color: var(--ab-navy);
}

.page-about .ab-timeline__card p {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.65;
  color: var(--ab-blue);
}

.page-about .ab-chapter--data {
  background: var(--ab-navy);
  color: rgba(255, 255, 255, 0.88);
  padding: 2rem 1.25rem 2.5rem;
  box-shadow: var(--shadow-gold);
}

.page-about .ab-chapter--data .ab-chapter__head {
  border-bottom-color: rgba(255, 255, 255, 0.18);
}

.page-about .ab-chapter--data .ab-chapter__head h2 {
  color: var(--ab-white);
}

.page-about .ab-chapter--data .ab-chapter__num {
  background: var(--ab-gold);
  color: var(--ab-navy);
}

.page-about .ab-datachapter__eyebrow {
  display: inline-block;
  margin: 0 0 1rem;
  padding: 0.25rem 0.6rem;
  background: var(--ab-red);
  color: var(--ab-white);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.12em;
}

.page-about .ab-chapter--data .rte p {
  color: rgba(255, 255, 255, 0.88);
}

.page-about .ab-chapter--data .ab-chapter__figure {
  border-color: var(--ab-gold);
  box-shadow: 6px 6px 0 rgba(212, 175, 55, 0.22);
}

.page-about .ab-datagrid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin-top: 2rem;
}

.page-about .ab-datum {
  position: relative;
  display: grid;
  gap: 0.2rem;
  padding: 1.1rem 1rem;
  background: var(--ab-white);
  border: var(--border-navy);
  box-shadow: 5px 5px 0 rgba(1, 11, 20, 0.55);
  cursor: default;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.page-about .ab-datum:hover,
.page-about .ab-datum:focus-within {
  transform: translate(-2px, -2px);
  box-shadow: 7px 7px 0 rgba(1, 11, 20, 0.55);
}

.page-about .ab-datum__value {
  font-size: 1.45rem;
  line-height: 1.2;
  font-weight: 700;
  color: var(--ab-navy);
}

.page-about .ab-datum__label {
  font-size: 0.85rem;
  color: var(--ab-blue);
}

.page-about .ab-datum__note {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  margin: 0.25rem 0 0;
  padding: 0;
  font-size: 0.78rem;
  line-height: 1.45;
  color: var(--ab-white);
  background: var(--ab-navy);
  transition: max-height 0.25s ease, opacity 0.25s ease, padding 0.25s ease;
}

.page-about .ab-datum:hover .ab-datum__note,
.page-about .ab-datum:focus-within .ab-datum__note {
  max-height: 70px;
  opacity: 1;
  padding: 0.35rem 0.5rem;
}

.page-about .ab-chapter--tianjin .ab-chapter__head {
  border-left: 5px solid var(--ab-red);
  padding-left: 1rem;
}

.page-about .ab-chapter--tianjin .ab-chapter__num {
  background: var(--ab-red);
  color: var(--ab-white);
}

.page-about .ab-chapter--mission {
  margin-top: 1rem;
  background: var(--ab-cream);
  border: var(--border-navy);
  box-shadow: var(--shadow-hard);
  padding: 2rem 1.5rem 2.75rem;
}

.page-about .ab-chapter--mission .ab-chapter__head {
  border-bottom-color: rgba(10, 35, 66, 0.12);
}

.page-about .ab-mission__quote {
  margin: 1.75rem 0 1.5rem;
  font-family: var(--font-editorial);
  font-size: clamp(1.4rem, 3vw, 1.9rem);
  line-height: 1.4;
  color: var(--ab-navy);
  border-left: 5px solid var(--ab-gold);
  padding-left: 1.25rem;
}

.page-about .ab-mission__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 2rem;
}

.page-about .btn:focus-visible,
.page-about .ab-toc a:focus-visible {
  outline: 3px solid var(--ab-orange);
  outline-offset: 2px;
}

@keyframes ab-rise {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-timeline__item {
    animation: none;
  }
}

@media (min-width: 768px) {
  .page-about .ab-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

  .page-about .ab-chapter--data {
    padding: 2.5rem 2rem 3rem;
  }

  .page-about .ab-timeline__marker {
    font-size: 0.75rem;
  }
}

@media (min-width: 992px) {
  .page-about .ab-story {
    grid-template-columns: minmax(250px, 300px) minmax(0, 1fr);
    gap: clamp(2rem, 5vw, 4.5rem);
    padding-bottom: 4rem;
  }

  .page-about .ab-story__rail {
    order: 1;
    position: sticky;
    top: var(--ab-sticky-top);
    max-height: calc(100vh - var(--ab-sticky-top) - 2rem);
    overflow-y: auto;
  }

  .page-about .ab-story__content {
    order: 2;
  }

  .page-about .ab-hero__title {
    font-size: clamp(2.6rem, 5vw, 3.6rem);
  }

  .page-about .ab-chapter {
    padding: 3rem 0 3.5rem;
    scroll-margin-top: 120px;
  }

  .page-about .ab-chapter--data {
    padding: 3rem 2.25rem 3.5rem;
    margin: 0.5rem 0 1rem;
  }

  .page-about .ab-chapter--mission {
    padding: 2.5rem 2.5rem 3rem;
  }

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

  .page-about .ab-timeline {
    gap: 2rem;
  }

  .page-about .ab-timeline__item {
    grid-template-columns: 96px minmax(0, 1fr);
    gap: 1.25rem;
  }

  .page-about .ab-timeline::before {
    left: 48px;
  }

  .page-about .ab-timeline__card {
    padding: 1.15rem 1.35rem;
  }
}