.page-about {
  --ab-line: rgba(147, 163, 177, .20);
  --ab-body-text: #C8D3DC;
  --ab-gap: 40px;
  background: var(--ink-0);
  color: var(--paper);
  overflow-x: hidden;
}

/* ---------- hero ---------- */
.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  padding: 44px 0 56px;
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  top: -34%;
  right: -28%;
  width: 132%;
  height: 168%;
  background: linear-gradient(145deg, rgba(46, 230, 214, .17) 0%, rgba(18, 167, 154, .06) 46%, rgba(14, 23, 32, 0) 74%);
  clip-path: polygon(40% 0, 100% 0, 100% 100%, 0 70%);
  pointer-events: none;
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--line-grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--line-grid) 1px, transparent 1px);
  background-size: 58px 58px;
  opacity: .22;
  pointer-events: none;
}

.page-about .ab-hero__inner {
  position: relative;
  z-index: 1;
}

.page-about .ab-hero__kicker {
  margin: 0 0 20px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .3em;
  color: var(--cyan);
}

.page-about .ab-hero__title {
  margin: 0;
  font-size: clamp(36px, 9.4vw, 82px);
  line-height: 1.04;
  letter-spacing: .035em;
  font-weight: 800;
  color: var(--paper);
}

.page-about .ab-hero__lede {
  margin: 24px 0 0;
  max-width: 40ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--ab-body-text);
}

.page-about .ab-hero__facts {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 34px 0 0;
  padding: 1px;
  background: var(--ab-line);
  border: 1px solid var(--ab-line);
}

.page-about .ab-hero__facts > li {
  background: var(--ink-0);
  padding: 14px 12px;
}

.page-about .ab-fact__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 24px;
  line-height: 1;
  color: var(--paper);
  letter-spacing: .02em;
}

.page-about .ab-fact__num small {
  font-size: 12px;
  color: var(--cool);
  margin-left: 4px;
}

.page-about .ab-fact__label {
  display: block;
  margin-top: 8px;
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--cool);
}

/* ---------- .page-about grid ---------- */
.page-about .ab-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 44px;
  padding-top: 48px;
  padding-bottom: 64px;
}

/* ---------- rail ---------- */
.page-about .ab-rail__head {
  margin-bottom: 28px;
}

.page-about .ab-rail__figure {
  margin: 0 0 20px;
  border: 1px solid var(--ab-line);
  overflow: hidden;
}

.page-about .ab-rail__label {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .26em;
  color: var(--tag);
}

.page-about .ab-rail__hint {
  margin: 8px 0 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--cool);
}

.page-about .ab-rail__list {
  list-style: none;
  margin: 0;
  padding: 0 0 0 20px;
  border-left: 1px solid var(--line-strong);
}

.page-about .ab-rail__item {
  position: relative;
}

.page-about .ab-rail__node {
  border-bottom: 1px solid rgba(147, 163, 177, .10);
}

.page-about .ab-rail__summary {
  position: relative;
  cursor: pointer;
  list-style: none;
  padding: 10px 0 12px;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2px;
}

.page-about .ab-rail__summary::-webkit-details-marker {
  display: none;
}

.page-about .ab-rail__dot {
  position: absolute;
  left: -25px;
  top: 14px;
  width: 9px;
  height: 9px;
  background: var(--ink-0);
  border: 1px solid var(--cyan-deep);
  transition: background .3s var(--ease), border-color .3s var(--ease);
}

.page-about .ab-rail__node[open] .ab-rail__dot {
  background: var(--tag);
  border-color: var(--tag);
}

.page-about .ab-rail__year {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--cyan);
  transition: color .3s var(--ease);
}

.page-about .ab-rail__node[open] .ab-rail__year {
  color: var(--tag);
}

.page-about .ab-rail__title {
  font-size: 15px;
  color: var(--paper);
  letter-spacing: .02em;
}

.page-about .ab-rail__text {
  margin: 0 0 12px;
  padding-left: 0;
  font-size: 13px;
  line-height: 1.75;
  color: var(--cool);
}

/* ---------- flow ---------- */
.page-about .ab-flow {
  display: flex;
  flex-direction: column;
  gap: var(--ab-gap);
  min-width: 0;
}

.page-about .ab-sec {
  position: relative;
  background: var(--ink-1);
  border: 1px solid var(--ab-line);
  padding: 26px 20px 30px;
  min-width: 0;
}

.page-about .ab-sec--repair { border-top: 3px solid var(--orange); }
.page-about .ab-sec--train  { border-top: 3px solid var(--cyan); }
.page-about .ab-sec--plain  { border-top: 3px solid var(--tag); }

.page-about .ab-sec__id {
  position: absolute;
  top: 12px;
  right: 14px;
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--cool);
  opacity: .32;
  transition: opacity .3s var(--ease), color .3s var(--ease);
}

.page-about .ab-sec:hover .ab-sec__id {
  opacity: 1;
  color: var(--tag);
}

.page-about .ab-sec__marker {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .2em;
  color: var(--tag);
}

.page-about .ab-sec__title {
  margin: 0 0 18px;
  font-size: clamp(22px, 4.4vw, 32px);
  line-height: 1.24;
  letter-spacing: .03em;
  font-weight: 700;
  color: var(--paper);
}

.page-about .ab-sec__prose p {
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ab-body-text);
  max-width: 40ch;
}

.page-about .ab-sec__prose p:last-child {
  margin-bottom: 0;
}

.page-about .ab-sec__prose--after {
  margin-top: 20px;
  padding-top: 18px;
  border-top: 1px dashed var(--ab-line);
}

.page-about .ab-sec__figure {
  margin: 0 0 20px;
  border: 1px solid var(--ab-line);
  overflow: hidden;
}

.page-about .ab-sec__figure + .ab-sec__prose {
  margin-top: 0;
}

.page-about .ab-sec__prose + .ab-sec__figure {
  margin-top: 20px;
}

.page-about .ab-sec__conclusion {
  margin: 22px 0 0;
  padding: 13px 16px;
  background: rgba(230, 197, 92, .08);
  border-left: 3px solid var(--tag);
  font-size: 15px;
  line-height: 1.7;
  font-weight: 700;
  color: var(--paper);
}

.page-about .ab-sec__conclusion--repair {
  background: rgba(255, 138, 61, .08);
  border-left-color: var(--orange);
}

.page-about .ab-sec__conclusion--train {
  background: rgba(46, 230, 214, .08);
  border-left-color: var(--cyan);
}

/* ---------- service grid ---------- */
.page-about .ab-svc {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--ab-line);
  border: 1px solid var(--ab-line);
}

.page-about .ab-svc__item {
  background: var(--ink-0);
  padding: 20px 18px;
}

.page-about .ab-svc__tagline {
  margin: 0 0 12px;
}

.page-about .ab-svc__heading {
  margin: 0 0 10px;
  font-size: 17px;
  line-height: 1.4;
  letter-spacing: .02em;
  color: var(--paper);
}

.page-about .ab-svc__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--ab-body-text);
}

/* ---------- crew numbers ---------- */
.page-about .ab-crew {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  margin: 22px 0 0;
  background: var(--ab-line);
  border: 1px solid var(--ab-line);
}

.page-about .ab-crew__cell {
  background: var(--ink-0);
  padding: 16px 12px;
  text-align: center;
}

.page-about .ab-crew__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 26px;
  line-height: 1;
  color: var(--cyan);
}

.page-about .ab-crew__label {
  display: block;
  margin-top: 8px;
  font-size: 12px;
  letter-spacing: .05em;
  color: var(--cool);
}

/* ---------- map svg ---------- */
.page-about .ab-map {
  display: block;
  width: 100%;
  height: auto;
  margin: 20px 0 0;
  border: 1px solid var(--ab-line);
  background: var(--ink-0);
}

/* ---------- cta ---------- */
.page-about .ab-cta {
  border: 1px solid var(--line-strong);
  background: linear-gradient(135deg, rgba(46, 230, 214, .07) 0%, rgba(14, 23, 32, 0) 58%);
  padding: 26px 20px;
}

.page-about .ab-cta__label {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .26em;
  color: var(--tag);
}

.page-about .ab-cta__text {
  margin: 0 0 22px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ab-body-text);
  max-width: 40ch;
}

.page-about .ab-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .ab-cta__aside {
  margin: 20px 0 0;
  font-size: 13px;
  color: var(--cool);
}

.page-about .ab-cta__link {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(46, 230, 214, .35);
  padding-bottom: 1px;
}

.page-about .ab-cta__link:hover {
  color: var(--orange);
  border-bottom-color: var(--orange);
}

.page-about .ab-cta__sep {
  margin: 0 8px;
  color: var(--cool);
}

/* ---------- media safety ---------- */
.page-about .media-frame {
  margin: 0;
}

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

/* ---------- medium screens ---------- */
@media (min-width: 640px) {
  .page-about .ab-hero {
    padding: 64px 0 76px;
  }

  .page-about .ab-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    max-width: 760px;
    margin-top: 40px;
  }

  .page-about .ab-hero__facts > li {
    padding: 18px 16px;
  }

  .page-about .ab-fact__num {
    font-size: 28px;
  }

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

  .page-about .ab-sec {
    padding: 32px 28px 36px;
  }

  .page-about .ab-sec__prose p {
    font-size: 16px;
  }

  .page-about .ab-cta {
    padding: 34px 30px;
  }
}

/* ---------- desktop: left rail + right cards ---------- */
@media (min-width: 900px) {
  .page-about .ab-body {
    grid-template-columns: 248px minmax(0, 1fr);
    gap: 52px;
    padding-top: 64px;
    padding-bottom: 88px;
  }

  .page-about .ab-rail {
    position: sticky;
    top: calc(var(--bar-h) + 24px);
    align-self: start;
    max-height: calc(100vh - var(--bar-h) - 48px);
    overflow-y: auto;
    padding-right: 4px;
  }

  .page-about .ab-flow {
    --ab-gap: 48px;
  }

  .page-about .ab-sec-off:nth-child(odd) {
    margin-right: 28px;
  }

  .page-about .ab-sec-off:nth-child(even) {
    margin-left: 34px;
  }

  .page-about .ab-sec__title {
    max-width: 22ch;
  }

  .page-about .ab-sec__figure {
    max-width: 560px;
  }

  .page-about .ab-cta {
    margin-right: 28px;
  }
}

@media (min-width: 1180px) {
  .page-about .ab-body {
    grid-template-columns: 272px minmax(0, 1fr);
    gap: 64px;
  }

  .page-about .ab-sec-off:nth-child(odd) {
    margin-right: 44px;
  }

  .page-about .ab-sec-off:nth-child(even) {
    margin-left: 48px;
  }
}

/* ---------- reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .ab-sec__id,
  .page-about .ab-rail__dot,
  .page-about .ab-rail__year {
    transition: none;
  }
}
</main>