.page-about {
  --ab-gut: clamp(18px, 4vw, 56px);
  --ab-rail: 0px;
  background: var(--ink);
  color: var(--ivory);
  padding-bottom: clamp(48px, 8vw, 96px);
}

.page-about .sd-crumbs {
  padding-top: clamp(18px, 3vw, 30px);
  font-family: var(--font-num);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--sage);
}
.page-about .sd-crumbs a {
  color: var(--sage);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}
.page-about .sd-crumbs a:hover,
.page-about .sd-crumbs a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--line-cyan);
}
.page-about .sd-crumbs .sd-crumbs__sep {
  margin: 0 8px;
  color: var(--moss);
}
.page-about .sd-crumbs [aria-current="page"] {
  color: var(--ivory);
}

/* ---------- Hero ---------- */
.page-about .ab-hero {
  margin-top: clamp(18px, 3vw, 30px);
}
.page-about .ab-hero__frame {
  display: grid;
  gap: clamp(20px, 3vw, 36px);
  padding: clamp(20px, 3.4vw, 44px);
  border: 1px solid var(--line-strong);
  background:
    linear-gradient(160deg, rgba(14, 29, 25, 0.94) 0%, rgba(6, 17, 15, 0.98) 62%),
    var(--graphite);
  position: relative;
}
.page-about .ab-hero__frame::before {
  content: "";
  position: absolute;
  inset: 8px;
  border: 1px solid var(--line-soft);
  pointer-events: none;
}
.page-about .ab-hero__frame::after {
  content: "";
  position: absolute;
  top: 0;
  left: clamp(20px, 3.4vw, 44px);
  width: 72px;
  height: 2px;
  background: var(--cyan);
  pointer-events: none;
}
.page-about .ab-hero__text {
  position: relative;
  z-index: 1;
}
.page-about .ab-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4.6vw, 3.6rem);
  line-height: 1.14;
  letter-spacing: -0.02em;
  font-weight: 700;
  margin: 0 0 18px;
  color: var(--ivory);
  max-width: 18ch;
}
.page-about .ab-hero__lede {
  font-size: clamp(15px, 1.4vw, 17px);
  line-height: 1.78;
  color: var(--sage);
  max-width: 56ch;
  margin: 0 0 24px;
}
.page-about .ab-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}
.page-about .ab-hero__chips {
  list-style: none;
  margin: 24px 0 0;
  padding: 16px 0 0;
  border-top: 1px solid var(--line);
  display: flex;
  flex-wrap: wrap;
  gap: 10px 22px;
  font-size: 12.5px;
  color: var(--sage);
}
.page-about .ab-hero__visual {
  position: relative;
  z-index: 1;
  margin: 0;
  border: 1px solid var(--line);
  background: var(--mineral);
  overflow: hidden;
}
.page-about .ab-hero__visual img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  filter: saturate(0.86) contrast(1.04);
}
.page-about .ab-hero__cap {
  padding: 12px 14px;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--sage);
  border-top: 1px solid var(--line);
  background: rgba(6, 17, 15, 0.72);
  font-family: var(--font-num);
}

/* ---------- Shell: toc + flow ---------- */
.page-about .ab-shell {
  margin-top: clamp(36px, 6vw, 72px);
  display: grid;
  gap: clamp(28px, 4vw, 52px);
}
.page-about .ab-toc {
  border-left: 2px solid var(--moss);
  padding-left: 14px;
}
.page-about .ab-toc__title {
  font-family: var(--font-num);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--cyan);
  margin: 0 0 12px;
}
.page-about .ab-toc__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}
.page-about .ab-toc__list a {
  display: block;
  padding: 8px 0;
  font-size: 13.5px;
  line-height: 1.5;
  color: var(--sage);
  text-decoration: none;
  border-bottom: 1px solid var(--line-soft);
  transition: color 160ms ease, padding-left 160ms ease;
}
.page-about .ab-toc__list a:hover,
.page-about .ab-toc__list a:focus-visible {
  color: var(--cyan);
  padding-left: 6px;
}

/* ---------- Chapter ---------- */
.page-about .ab-flow {
  display: grid;
  gap: clamp(40px, 6vw, 84px);
  min-width: 0;
}
.page-about .ab-chapter {
  scroll-margin-top: 96px;
  padding-top: clamp(10px, 2vw, 20px);
  border-top: 1px solid var(--line-strong);
}
.page-about .ab-chapter--alt {
  background: linear-gradient(180deg, rgba(27, 43, 39, 0.5) 0%, rgba(6, 17, 15, 0) 78%);
  border-top-color: var(--line-cyan);
  padding: clamp(24px, 3.4vw, 40px) clamp(16px, 2.6vw, 32px) clamp(8px, 1.6vw, 16px);
}
.page-about .ab-chapter__head {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 16px;
  align-items: start;
  margin-bottom: clamp(18px, 2.6vw, 30px);
}
.page-about .ab-chapter__no {
  font-family: var(--font-num);
  font-size: clamp(22px, 2.6vw, 30px);
  font-weight: 700;
  color: var(--moss);
  line-height: 1;
  padding-top: 4px;
}
.page-about .ab-chapter h2 {
  font-family: var(--font-display);
  font-size: clamp(1.4rem, 2.6vw, 2rem);
  line-height: 1.24;
  letter-spacing: -0.02em;
  font-weight: 700;
  color: var(--ivory);
  margin: 0 0 10px;
}
.page-about .ab-chapter__quote {
  font-family: var(--font-editorial);
  font-size: clamp(14px, 1.5vw, 16px);
  line-height: 1.7;
  color: var(--cyan-soft);
  margin: 0;
  opacity: 0.9;
}
.page-about .ab-chapter__body {
  display: grid;
  gap: clamp(20px, 3vw, 32px);
}
.page-about .ab-prose p {
  font-size: 16px;
  line-height: 1.78;
  color: rgba(232, 228, 214, 0.84);
  margin: 0 0 16px;
  max-width: 68ch;
}
.page-about .ab-prose p:last-child {
  margin-bottom: 0;
}

/* facts */
.page-about .ab-facts {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}
.page-about .ab-fact {
  background: var(--graphite);
  padding: 16px 14px;
  display: grid;
  gap: 6px;
}
.page-about .ab-fact__num {
  font-family: var(--font-num);
  font-size: clamp(20px, 2.4vw, 26px);
  font-weight: 700;
  color: var(--clay);
  line-height: 1;
  font-variant-numeric: tabular-nums;
}
.page-about .ab-fact__label {
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--sage);
}

/* ---------- editorial ---------- */
.page-about .ab-editorial {
  display: grid;
  gap: clamp(18px, 3vw, 30px);
  align-items: start;
}
.page-about .ab-editorial__figure {
  margin: 0;
  border: 1px solid var(--line);
  background: var(--mineral);
  overflow: hidden;
}
.page-about .ab-editorial__figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}
.page-about .ab-editorial__figure figcaption {
  padding: 10px 14px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--sage);
  border-top: 1px solid var(--line);
}
.page-about .ab-editorial__copy p {
  font-size: 16px;
  line-height: 1.78;
  color: rgba(232, 228, 214, 0.84);
  margin: 0 0 16px;
  max-width: 66ch;
}
.page-about .ab-editorial__copy p:last-child {
  margin-bottom: 0;
}

/* check flow */
.page-about .ab-check {
  list-style: none;
  margin: clamp(24px, 4vw, 40px) 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}
.page-about .ab-check__step {
  position: relative;
  background: var(--graphite);
  border: 1px solid var(--line);
  border-left: 2px solid var(--cyan);
  padding: 18px 16px 16px 44px;
}
.page-about .ab-check__tick {
  position: absolute;
  left: 14px;
  top: 19px;
  width: 16px;
  height: 16px;
  border: 1.5px solid var(--cyan);
  background: rgba(95, 242, 200, 0.1);
}
.page-about .ab-check__tick::after {
  content: "";
  position: absolute;
  left: 4px;
  top: 1px;
  width: 4px;
  height: 8px;
  border-right: 1.6px solid var(--cyan);
  border-bottom: 1.6px solid var(--cyan);
  transform: rotate(42deg);
}
.page-about .ab-check__name {
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 700;
  color: var(--ivory);
  margin: 0 0 8px;
  letter-spacing: 0.01em;
}
.page-about .ab-check__desc {
  font-size: 14px;
  line-height: 1.7;
  color: var(--sage);
  margin: 0 0 10px;
}
.page-about .ab-check__tag {
  display: inline-block;
  font-family: var(--font-num);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  color: var(--ink);
  background: var(--cyan);
  padding: 3px 7px;
}

.page-about .ab-diagram {
  margin: clamp(24px, 4vw, 40px) 0 0;
  border: 1px solid var(--line);
  background: var(--mineral);
  overflow: hidden;
}
.page-about .ab-diagram img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}
.page-about .ab-diagram figcaption {
  padding: 10px 14px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--sage);
  border-top: 1px solid var(--line);
}

/* ---------- roles ---------- */
.page-about .ab-roles {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}
.page-about .ab-role {
  background: var(--graphite);
  padding: 16px;
  display: grid;
  gap: 6px;
  outline: none;
  transition: background 160ms ease;
}
.page-about .ab-role__name {
  font-family: var(--font-display);
  font-size: 14.5px;
  font-weight: 700;
  color: var(--ivory);
  letter-spacing: 0.01em;
  display: flex;
  align-items: center;
  gap: 8px;
}
.page-about .ab-role__name::before {
  content: "";
  width: 6px;
  height: 6px;
  background: var(--moss);
  flex: none;
}
.page-about .ab-role__duty {
  font-size: 13.5px;
  line-height: 1.68;
  color: var(--sage);
  padding-left: 14px;
}
.page-about .ab-role:hover,
.page-about .ab-role:focus-visible {
  background: var(--mineral);
}
.page-about .ab-role:hover .ab-role__name::before,
.page-about .ab-role:focus-visible .ab-role__name::before {
  background: var(--cyan);
}
.page-about .ab-role:focus-visible {
  box-shadow: inset 0 0 0 2px var(--cyan);
}

/* ---------- timeline ---------- */
.page-about .ab-timeline {
  position: relative;
  display: grid;
  gap: 0;
  padding-left: 18px;
  border-left: 1px solid var(--line-strong);
}
.page-about .ab-milestone {
  position: relative;
  padding: 0 0 clamp(22px, 3vw, 32px) clamp(16px, 2vw, 24px);
}
.page-about .ab-milestone:last-child {
  padding-bottom: 0;
}
.page-about .ab-milestone::before {
  content: "";
  position: absolute;
  left: calc(-18px - 5px);
  top: 6px;
  width: 9px;
  height: 9px;
  background: var(--ink);
  border: 2px solid var(--cyan);
  transform: rotate(45deg);
}
.page-about .ab-milestone__no {
  display: inline-block;
  font-family: var(--font-num);
  font-size: 11.5px;
  letter-spacing: 0.12em;
  color: var(--cyan);
  margin-bottom: 6px;
}
.page-about .ab-milestone__title {
  font-family: var(--font-display);
  font-size: clamp(15px, 1.7vw, 17px);
  font-weight: 700;
  color: var(--ivory);
  margin: 0 0 6px;
  letter-spacing: -0.01em;
}
.page-about .ab-milestone__desc {
  font-size: 14px;
  line-height: 1.72;
  color: var(--sage);
  margin: 0 0 8px;
  max-width: 60ch;
}
.page-about .ab-milestone__ver {
  display: inline-block;
  font-family: var(--font-num);
  font-size: 10.5px;
  letter-spacing: 0.08em;
  color: var(--sage);
  border: 1px solid var(--line-strong);
  padding: 2px 8px;
}

/* ---------- ecosystem ---------- */
.page-about .ab-eco {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.page-about .ab-eco__tag {
  font-size: 13px;
  line-height: 1.4;
  padding: 9px 13px;
  color: var(--ivory);
  background: linear-gradient(145deg, rgba(62, 107, 87, 0.46), rgba(31, 77, 58, 0.32));
  border: 1px solid rgba(95, 242, 200, 0.22);
  transition: border-color 160ms ease, background 160ms ease;
}
.page-about .ab-eco__tag:hover {
  border-color: var(--line-cyan);
  background: linear-gradient(145deg, rgba(62, 107, 87, 0.62), rgba(31, 77, 58, 0.44));
}

/* ---------- compliance ---------- */
.page-about .ab-chapter--last {
  border-top-color: var(--moss);
}
.page-about .ab-compliance {
  display: grid;
  gap: 14px;
}
.page-about .ab-compliance__card {
  background: var(--graphite);
  border: 1px solid var(--line);
  padding: 20px 18px;
}
.page-about .ab-compliance__title {
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 700;
  color: var(--ivory);
  margin: 0 0 10px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line-soft);
  letter-spacing: 0.01em;
}
.page-about .ab-compliance__card p {
  font-size: 14px;
  line-height: 1.75;
  color: var(--sage);
  margin: 0 0 10px;
}
.page-about .ab-compliance__meta {
  font-family: var(--font-num);
  font-size: 12px !important;
  letter-spacing: 0.05em;
  color: var(--cyan) !important;
}
.page-about .ab-compliance__list {
  list-style: none;
  margin: 0 0 12px;
  padding: 0;
  display: grid;
  gap: 10px;
}
.page-about .ab-compliance__list li {
  display: grid;
  gap: 4px;
}
.page-about .ab-compliance__k {
  font-family: var(--font-num);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--moss);
  text-transform: uppercase;
}
.page-about .ab-compliance__v {
  font-size: 14px;
  line-height: 1.6;
  color: var(--ivory);
  word-break: break-word;
}
.page-about .ab-compliance__note {
  font-size: 12.5px !important;
  line-height: 1.68;
  color: rgba(157, 179, 166, 0.86) !important;
  padding-top: 10px;
  border-top: 1px solid var(--line-soft);
  margin: 0 !important;
}
.page-about .ab-compliance .sd-copy {
  justify-self: start;
  background: transparent;
  border: 1px solid var(--line-strong);
  color: var(--ivory);
  font-family: var(--font-num);
  font-size: 13px;
  padding: 9px 12px;
  min-height: 44px;
  cursor: pointer;
  text-align: left;
  word-break: break-all;
  transition: border-color 160ms ease, color 160ms ease, background 160ms ease;
}
.page-about .ab-compliance .sd-copy:hover {
  border-color: var(--line-cyan);
  color: var(--cyan);
}
.page-about .ab-compliance .sd-copy:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}
.page-about .ab-compliance .sd-copy[data-copied] {
  border-color: var(--cyan);
  color: var(--ink);
  background: var(--cyan);
}

/* ---------- next ---------- */
.page-about .ab-next {
  margin-top: clamp(24px, 4vw, 40px);
  padding: clamp(18px, 2.8vw, 28px);
  border: 1px solid var(--line-strong);
  background:
    repeating-linear-gradient(90deg, rgba(95, 242, 200, 0.16) 0 1px, transparent 1px 24px),
    var(--ink-deep);
}
.page-about .ab-next__text {
  font-size: 15px;
  line-height: 1.75;
  color: rgba(232, 228, 214, 0.86);
  margin: 0 0 16px;
  max-width: 60ch;
}
.page-about .ab-next__links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- media queries ---------- */
@media (min-width: 720px) {
  .page-about .ab-facts {
    grid-template-columns: repeat(4, 1fr);
  }
  .page-about .ab-compliance {
    grid-template-columns: 1fr 1fr;
  }
  .page-about .ab-check {
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
  }
  .page-about .ab-roles {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero__frame {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    align-items: stretch;
  }
  .page-about .ab-editorial {
    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
  }
}

@media (min-width: 1080px) {
  .page-about .ab-shell {
    grid-template-columns: 236px minmax(0, 1fr);
    align-items: start;
  }
  .page-about .ab-toc {
    position: sticky;
    top: 96px;
  }
  .page-about .ab-chapter__body {
    grid-template-columns: minmax(0, 1fr) 250px;
    align-items: start;
  }
  .page-about .ab-chapter--alt .ab-chapter__body {
    grid-template-columns: minmax(0, 1fr);
  }
  .page-about .ab-chapter h2 {
    max-width: 26ch;
  }
}

@media (max-width: 719px) {
  .page-about .ab-hero__actions .sd-btn,
  .page-about .ab-next__links .sd-btn {
    flex: 1 1 auto;
    text-align: center;
  }
  .page-about .ab-facts {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-toc__list a,
  .page-about .ab-role,
  .page-about .ab-eco__tag,
  .page-about .ab-compliance .sd-copy {
    transition: none;
  }
}
<<<END>>>