.page-about {
  --about-gap: clamp(28px, 4.5vw, 56px);
  --about-hero-pad: clamp(36px, 6.5vw, 92px);
  padding-bottom: clamp(48px, 8vw, 112px);
}

/* ---------- breadcrumb ---------- */
.page-about .breadcrumb {
  padding: 22px 0 0;
  font-size: 13px;
  color: var(--index-600);
}
.page-about .breadcrumb a {
  color: var(--mist-200);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color .2s var(--ease), color .2s var(--ease);
}
.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--signal-400);
  border-bottom-color: var(--signal-400);
}

/* ---------- hero ---------- */
.page-about .about-hero {
  position: relative;
  padding: var(--about-hero-pad) 0 clamp(28px, 4vw, 52px);
  border-bottom: 1px solid var(--line-700);
  overflow: hidden;
}
.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -80px;
  top: 12%;
  width: min(46vw, 520px);
  aspect-ratio: 1 / 1;
  background:
    radial-gradient(closest-side, rgba(66, 245, 209, .14), transparent 70%),
    repeating-linear-gradient(90deg, var(--line-700) 0 1px, transparent 1px 34px),
    repeating-linear-gradient(0deg, var(--line-700) 0 1px, transparent 1px 34px);
  opacity: .55;
  pointer-events: none;
}
.page-about .about-hero__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 34px;
  position: relative;
  z-index: 1;
}
.page-about .about-hero .eyebrow {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .24em;
  text-transform: uppercase;
  color: var(--round-500);
}
.page-about .about-hero__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(52px, 11vw, 132px);
  line-height: .92;
  letter-spacing: -.02em;
  color: var(--archive-050);
}
.page-about .about-hero__sub {
  margin: 22px 0 0;
  max-width: 46ch;
  font-size: clamp(16px, 1.6vw, 18px);
  line-height: 1.75;
  color: var(--mist-200);
}
.page-about .about-hero__links {
  margin: 28px 0 0;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .hero-facts {
  margin: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line-700);
  border: 1px solid var(--line-700);
}
.page-about .hero-fact {
  background: var(--base-900);
  padding: 18px 16px;
}
.page-about .hero-fact dt {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  color: var(--index-600);
}
.page-about .hero-fact dd {
  margin: 10px 0 0;
  display: flex;
  align-items: baseline;
  gap: 4px;
  color: var(--signal-400);
}
.page-about .hero-fact .num {
  font-family: var(--font-mono);
  font-size: clamp(26px, 4.4vw, 40px);
  line-height: 1;
  letter-spacing: -.02em;
}
.page-about .hero-fact__suffix {
  font-size: 13px;
  color: var(--mist-200);
}

/* ---------- layout grid ---------- */
.page-about .about-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--about-gap) 0;
  padding-top: clamp(28px, 4vw, 52px);
}
.page-about .about-col {
  min-width: 0;
}

/* ---------- rail ---------- */
.page-about .about-rail {
  order: -1;
  border-bottom: 1px solid var(--line-700);
  padding-bottom: 14px;
  min-width: 0;
}
.page-about .rail-title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .24em;
  text-transform: uppercase;
  color: var(--index-600);
}
.page-about .rail-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 0;
  overflow-x: auto;
  scrollbar-width: none;
}
.page-about .rail-list::-webkit-scrollbar {
  display: none;
}
.page-about .rail-item {
  flex: 0 0 auto;
}
.page-about .rail-link {
  display: block;
  white-space: nowrap;
  padding: 7px 16px 7px 0;
  font-size: 13px;
  color: var(--mist-200);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}
.page-about .rail-link:hover,
.page-about .rail-link:focus-visible {
  color: var(--signal-400);
  border-bottom-color: var(--signal-400);
}

/* ---------- sections ---------- */
.page-about .about-sec {
  padding: clamp(30px, 4.4vw, 54px) 0;
  border-top: 1px solid var(--line-700);
}
.page-about .about-sec:first-child {
  border-top: 0;
  padding-top: 0;
}
.page-about .sec-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 16px;
}
.page-about .sec-num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--round-500);
  flex: 0 0 auto;
}
.page-about .sec-head h2 {
  margin: 0;
}
.page-about .about-sec .body-text {
  max-width: 62ch;
  margin: 0 0 16px;
  font-size: 16px;
  line-height: 1.8;
  color: var(--archive-050);
}
.page-about .about-sec .body-text:last-child {
  margin-bottom: 0;
}
.page-about .about-sec .body-text a {
  color: var(--signal-400);
  text-decoration: none;
  border-bottom: 1px solid var(--line-700);
  transition: border-color .2s var(--ease);
}
.page-about .about-sec .body-text a:hover,
.page-about .about-sec .body-text a:focus-visible {
  border-bottom-color: var(--signal-400);
}
.page-about .note {
  max-width: 62ch;
  margin: 20px 0 0;
  padding-left: 16px;
  border-left: 1px solid var(--line-700);
  font-size: 13px;
  line-height: 1.7;
  color: var(--index-600);
}
.page-about .note__label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--round-500);
  margin-right: 8px;
}

/* ---------- stat grid ---------- */
.page-about .stat-grid {
  margin: 24px 0 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line-700);
  border: 1px solid var(--line-700);
}
.page-about .stat-cell {
  background: var(--base-900);
  padding: 22px 18px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.page-about .stat-cell__v {
  font-family: var(--font-mono);
  font-size: clamp(28px, 4.6vw, 42px);
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--signal-400);
}
.page-about .stat-cell__v--amber {
  color: var(--round-500);
}
.page-about .stat-cell__l {
  font-size: 13px;
  line-height: 1.6;
  color: var(--mist-200);
}

/* ---------- team ---------- */
.page-about .team-grid {
  margin: 24px 0 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line-700);
  border: 1px solid var(--line-700);
}
.page-about .team-cell {
  background: var(--layer-800);
  padding: 22px 20px;
}
.page-about .team-cell h3 {
  margin: 0 0 10px;
  font-size: 17px;
  color: var(--archive-050);
}
.page-about .team-cell p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--mist-200);
}

.page-about .team-figure {
  margin: 28px 0 0;
}

/* ---------- flow ---------- */
.page-about .flow-list {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  border-top: 1px solid var(--line-700);
}
.page-about .flow-item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 18px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line-700);
}
.page-about .flow-idx {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--round-500);
  padding-top: 3px;
}
.page-about .flow-name {
  margin: 0 0 6px;
  font-size: 15px;
  font-weight: 600;
  color: var(--archive-050);
}
.page-about .flow-item p {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist-200);
}

/* ---------- timeline ---------- */
.page-about .tl-figure {
  margin: 24px 0 32px;
}
.page-about .tl-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
}
.page-about .tl-item {
  position: relative;
  padding: 30px 0 12px;
  border-top: 1px solid var(--line-700);
}
.page-about .tl-item:first-child {
  border-top-color: var(--round-500);
}
.page-about .tl-dot {
  position: absolute;
  top: -5px;
  left: 0;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--round-500);
}
.page-about .tl-dot--current {
  background: var(--signal-400);
  box-shadow: 0 0 0 4px rgba(66, 245, 209, .16);
}
.page-about .tl-v {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--index-600);
}
.page-about .tl-v--amber {
  color: var(--round-500);
}
.page-about .tl-name {
  margin: 0 0 10px;
  font-size: 17px;
  color: var(--archive-050);
}
.page-about .tl-desc {
  margin: 0;
  max-width: 42ch;
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist-200);
  transition: color .25s var(--ease);
}
.page-about .tl-item:hover .tl-desc,
.page-about .tl-item:focus-within .tl-desc {
  color: var(--archive-050);
}
.page-about .tl-item:hover .tl-dot {
  transform: scale(1.25);
}
.page-about .tl-dot {
  transition: transform .25s var(--ease);
}

/* ---------- mobile / spec list ---------- */
.page-about .mobile-figure {
  margin: 24px 0 0;
}
.page-about .spec-list {
  margin: 26px 0 20px;
  padding: 0;
  border-top: 1px solid var(--line-700);
}
.page-about .spec-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line-700);
}
.page-about .spec-row dt {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--round-500);
}
.page-about .spec-row dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--archive-050);
}

/* ---------- closing ---------- */
.page-about .about-close {
  margin-top: clamp(30px, 4vw, 52px);
  padding: clamp(28px, 4vw, 44px) clamp(20px, 3vw, 36px);
  background: var(--layer-800);
  border-left: 3px solid var(--signal-400);
}
.page-about .close-line {
  margin: 0 0 20px;
  max-width: 40ch;
  font-family: var(--font-display);
  font-size: clamp(19px, 2.4vw, 26px);
  line-height: 1.55;
  color: var(--archive-050);
}
.page-about .close-anchor {
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 16px;
  padding-top: 16px;
  border-top: 1px solid var(--line-700);
  font-size: 13px;
}
.page-about .anchor-k {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--index-600);
}
.page-about .anchor-v {
  color: var(--mist-200);
}
.page-about .anchor-link {
  margin-left: auto;
  color: var(--signal-400);
  text-decoration: none;
  border-bottom: 1px solid var(--line-700);
  padding-bottom: 2px;
  transition: border-color .2s var(--ease);
}
.page-about .anchor-link:hover,
.page-about .anchor-link:focus-visible {
  border-bottom-color: var(--signal-400);
}

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

/* ---------- responsive ---------- */
@media (min-width: 640px) {
  .page-about .stat-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .spec-row {
    grid-template-columns: minmax(0, 150px) minmax(0, 1fr);
    gap: 20px;
    align-items: baseline;
  }
}

@media (min-width: 760px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1fr) minmax(0, 320px);
    align-items: end;
    gap: clamp(28px, 5vw, 72px);
  }
  .page-about .hero-facts {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .team-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .tl-list {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }
  .page-about .tl-item {
    padding: 30px 18px 8px 0;
  }
  .page-about .tl-desc {
    max-width: none;
  }
}

@media (min-width: 1024px) {
  .page-about .about-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 3fr);
    column-gap: clamp(40px, 5.5vw, 84px);
  }
  .page-about .about-rail {
    order: 0;
    border-bottom: 0;
    padding-bottom: 0;
  }
  .page-about .rail-sticky {
    position: sticky;
    top: calc(var(--head-h) + 32px);
  }
  .page-about .rail-list {
    display: block;
    overflow: visible;
    border-left: 1px solid var(--line-700);
  }
  .page-about .rail-link {
    white-space: normal;
    padding: 9px 0 9px 16px;
    margin-left: -1px;
    border-bottom: 0;
    border-left: 2px solid transparent;
    transition: color .2s var(--ease), border-left-color .2s var(--ease);
  }
  .page-about .rail-link:hover,
  .page-about .rail-link:focus-visible {
    border-bottom-color: transparent;
    border-left-color: var(--signal-400);
  }
}

@media (min-width: 1200px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1fr) minmax(0, 400px);
  }
  .page-about .hero-facts {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tl-dot,
  .page-about .tl-desc,
  .page-about .rail-link,
  .page-about .breadcrumb a,
  .page-about .about-sec .body-text a,
  .page-about .anchor-link {
    transition: none;
  }
  .page-about .tl-item:hover .tl-dot {
    transform: none;
  }
}
<<<END>>>