.page-about {
  --ab-hard: 8px 8px 0 rgba(5, 17, 14, 0.9);
  --ab-line: rgba(47, 230, 200, 0.22);
  --ab-line-soft: rgba(47, 230, 200, 0.12);
  --ab-body: rgba(242, 247, 244, 0.82);
  background: var(--pitch);
  color: var(--bone);
  overflow-x: hidden;
}

.page-about .ab-copy {
  margin: 0 0 14px;
  font-size: 16px;
  line-height: 1.82;
  color: var(--ab-body);
  max-width: 66ch;
}

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

/* ---------- Hero ---------- */

.page-about .ab-hero {
  position: relative;
  isolation: isolate;
  padding: 36px 0 44px;
  border-bottom: 2px solid var(--cyan-line);
  background:
    radial-gradient(760px 380px at 82% -12%, rgba(47, 230, 200, 0.16), transparent 72%),
    radial-gradient(520px 300px at 4% 112%, rgba(255, 138, 61, 0.14), transparent 72%),
    var(--pitch);
}

.page-about .ab-hero-photo {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 42%;
  opacity: 0.24;
  z-index: 0;
  filter: grayscale(0.35) contrast(1.15) saturate(0.85);
  -webkit-mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.95), transparent 92%);
  mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.95), transparent 92%);
}

.page-about .ab-hero-inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 34px;
}

.page-about .ab-hero-copy h1 {
  margin: 10px 0 16px;
  font-size: clamp(30px, 8vw, 44px);
  line-height: 1.14;
  letter-spacing: 0.02em;
  font-weight: 900;
}

.page-about .ab-hero-copy .kit-lede {
  max-width: 54ch;
  color: var(--ab-body);
  line-height: 1.82;
}

.page-about .ab-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

.page-about .ab-hero-cards {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.page-about .ab-card {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 14px 12px 16px;
  border: 2px solid var(--ab-line);
  background: rgba(18, 53, 43, 0.88);
  box-shadow: 5px 5px 0 rgba(5, 17, 14, 0.9);
}

.page-about .ab-card:nth-child(2n) {
  margin-top: 18px;
}

.page-about .ab-card--accent {
  border-color: var(--orange);
  box-shadow: 5px 5px 0 rgba(255, 138, 61, 0.55);
}

.page-about .ab-card-num {
  font-family: var(--mono);
  font-size: clamp(22px, 6vw, 30px);
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--cyan);
  word-break: break-word;
}

.page-about .ab-card--accent .ab-card-num {
  color: var(--orange);
}

.page-about .ab-card-label {
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--mist);
}

/* ---------- Chapter index ---------- */

.page-about .ab-toc {
  background: var(--ink);
  border-bottom: 2px solid var(--cyan-line);
}

.page-about .ab-toc-list {
  display: flex;
  margin: 0;
  padding: 0;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .ab-toc-list li {
  flex: 0 0 auto;
}

.page-about .ab-toc-list a {
  display: block;
  padding: 15px 16px;
  font-size: 13.5px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--bone);
  text-decoration: none;
  border-right: 1px solid var(--ab-line-soft);
  transition: color 140ms var(--ease), background 140ms var(--ease);
}

.page-about .ab-toc-list a:hover,
.page-about .ab-toc-list a:focus-visible {
  color: var(--cyan);
  background: var(--cyan-soft);
  outline: none;
}

.page-about .ab-toc-no {
  display: inline-block;
  margin-right: 8px;
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--orange);
}

/* ---------- Section shell ---------- */

.page-about .ab-section {
  padding: 46px 0;
  border-bottom: 1px solid var(--ab-line-soft);
}

.page-about .ab-head h2,
.page-about .ab-desk-body h2,
.page-about .ab-dmqs-body h2,
.page-about .ab-cta h2 {
  margin: 10px 0 16px;
  font-size: clamp(25px, 5.4vw, 38px);
  line-height: 1.16;
  letter-spacing: 0.015em;
  font-weight: 900;
}

/* ---------- View ---------- */

.page-about .ab-view-grid {
  display: grid;
  gap: 28px;
}

.page-about .ab-view-list {
  display: grid;
  align-content: start;
}

.page-about .ab-view-item {
  padding: 18px 0;
  border-top: 2px solid var(--ab-line);
  transition: border-color 160ms var(--ease), padding-left 160ms var(--ease);
}

.page-about .ab-view-item:last-child {
  border-bottom: 2px solid var(--ab-line);
}

.page-about .ab-view-item:hover {
  border-color: var(--cyan);
  padding-left: 8px;
}

.page-about .ab-view-no {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--orange);
}

.page-about .ab-view-item h3 {
  margin: 6px 0 8px;
  font-size: 19px;
  font-weight: 800;
  letter-spacing: 0.02em;
  color: var(--bone);
}

.page-about .ab-view-item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--ab-body);
}

/* ---------- Stat strip ---------- */

.page-about .ab-strip {
  padding: 30px 0;
  background: var(--ink);
  border-top: 3px solid var(--cyan);
  border-bottom: 3px solid var(--orange);
}

.page-about .ab-strip-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px 16px;
}

.page-about .ab-stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
  border-left: 2px solid var(--ab-line);
  padding-left: 12px;
}

.page-about .ab-stat-value {
  font-family: var(--mono);
  font-size: clamp(20px, 5.6vw, 27px);
  font-weight: 700;
  color: var(--cyan);
  line-height: 1.1;
}

.page-about .ab-stat:nth-child(3n + 1) .ab-stat-value {
  color: var(--mint);
}

.page-about .ab-stat-label {
  font-size: 12.5px;
  line-height: 1.55;
  color: var(--mist);
}

/* ---------- Quote ---------- */

.page-about .ab-quote {
  padding: 44px 0;
  border-bottom: 2px solid var(--cyan-line);
  background:
    linear-gradient(118deg, rgba(47, 230, 200, 0.12), rgba(255, 138, 61, 0.12) 62%, transparent 92%),
    var(--pitch);
}

.page-about .ab-quote blockquote {
  margin: 0;
  max-width: 30ch;
}

.page-about .ab-quote p {
  margin: 0;
  font-size: clamp(21px, 5vw, 33px);
  font-weight: 900;
  line-height: 1.36;
  letter-spacing: 0.015em;
}

.page-about .ab-quote cite {
  display: block;
  margin-top: 16px;
  font-family: var(--mono);
  font-style: normal;
  font-size: 12.5px;
  letter-spacing: 0.1em;
  color: var(--mist);
}

/* ---------- Desk ---------- */

.page-about .ab-desk-grid {
  display: grid;
  gap: 30px;
}

.page-about .ab-desk-figure,
.page-about .ab-dmqs-figure {
  position: relative;
  margin: 0;
  border: 2px solid var(--cyan-line);
  box-shadow: var(--ab-hard);
  overflow: hidden;
  background: var(--panel);
}

.page-about .ab-desk-figure img,
.page-about .ab-dmqs-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  filter: saturate(0.86) contrast(1.08);
}

.page-about .ab-desk-figure::after,
.page-about .ab-dmqs-figure::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(160deg, rgba(47, 230, 200, 0.16), transparent 48%, rgba(255, 138, 61, 0.16));
}

.page-about .ab-figcap {
  position: absolute;
  left: 0;
  bottom: 0;
  z-index: 1;
  padding: 7px 11px;
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--ink);
  background: var(--cyan);
}

.page-about .ab-fact-list {
  margin: 20px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-fact-list li {
  display: grid;
  gap: 4px;
  padding: 14px 0;
  border-top: 1px solid var(--ab-line);
}

.page-about .ab-fact-list li:last-child {
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-fact-key {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--orange);
}

.page-about .ab-fact-txt {
  font-size: 15px;
  line-height: 1.78;
  color: var(--ab-body);
}

/* ---------- Engine ---------- */

.page-about .ab-engine-grid {
  display: grid;
  gap: 1px;
  margin-top: 26px;
  background: var(--cyan-line);
  border: 2px solid var(--cyan-line);
}

.page-about .ab-engine-item {
  padding: 22px 18px;
  background: var(--pitch);
  transition: background 160ms var(--ease);
}

.page-about .ab-engine-item:hover {
  background: var(--panel);
}

.page-about .ab-engine-no {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--orange);
}

.page-about .ab-engine-item h3 {
  margin: 8px 0 8px;
  font-size: 18px;
  font-weight: 800;
  letter-spacing: 0.02em;
}

.page-about .ab-engine-item p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.78;
  color: var(--ab-body);
}

/* ---------- DMQS ---------- */

.page-about .ab-dmqs-grid {
  display: grid;
  gap: 30px;
}

.page-about .ab-device-list {
  margin: 18px 0 24px;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 12px;
}

.page-about .ab-device-list li {
  position: relative;
  padding-left: 22px;
  font-size: 15px;
  line-height: 1.7;
  color: var(--ab-body);
}

.page-about .ab-device-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 8px;
  height: 8px;
  background: var(--orange);
}

/* ---------- Roadmap ---------- */

.page-about .ab-road-list {
  margin: 26px 0 0;
  padding: 0 0 0 26px;
  list-style: none;
  border-left: 2px solid var(--cyan-line);
  display: grid;
  gap: 16px;
}

.page-about .ab-road-item {
  position: relative;
}

.page-about .ab-road-item::before {
  content: "";
  position: absolute;
  left: -34px;
  top: 16px;
  width: 12px;
  height: 12px;
  background: var(--pitch);
  border: 2px solid var(--cyan);
  transition: background 160ms var(--ease);
}

.page-about .ab-road-item:has(details[open])::before {
  background: var(--orange);
  border-color: var(--orange);
}

.page-about .ab-road-item details {
  border: 2px solid var(--ab-line);
  background: rgba(18, 53, 43, 0.6);
  transition: border-color 160ms var(--ease);
}

.page-about .ab-road-item details[open] {
  border-color: var(--cyan);
}

.page-about .ab-road-item summary {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 15px 16px;
  list-style: none;
  cursor: pointer;
  font-size: 16px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--bone);
}

.page-about .ab-road-item summary::-webkit-details-marker {
  display: none;
}

.page-about .ab-road-item summary:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.page-about .ab-road-item summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--mono);
  font-size: 18px;
  line-height: 1;
  color: var(--orange);
}

.page-about .ab-road-item details[open] summary::after {
  content: "–";
}

.page-about .ab-road-no {
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: 0.12em;
  color: var(--cyan);
  white-space: nowrap;
}

.page-about .ab-road-title {
  min-width: 0;
}

.page-about .ab-road-body {
  padding: 14px 16px 18px;
  font-size: 14.5px;
  line-height: 1.82;
  color: var(--ab-body);
  border-top: 2px solid var(--ab-line);
}

/* ---------- CTA ---------- */

.page-about .ab-cta {
  padding: 44px 0 52px;
  border-top: 3px solid var(--cyan);
  background:
    linear-gradient(132deg, rgba(47, 230, 200, 0.14), rgba(255, 138, 61, 0.16) 72%, transparent),
    var(--ink);
}

.page-about .ab-cta-inner {
  display: grid;
  gap: 22px;
  align-items: center;
}

.page-about .ab-cta-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- Responsive ---------- */

@media (min-width: 700px) {
  .page-about .ab-strip-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 26px 20px;
  }

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

  .page-about .ab-fact-list li {
    grid-template-columns: 96px minmax(0, 1fr);
    gap: 16px;
    align-items: baseline;
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero {
    padding: 56px 0 72px;
  }

  .page-about .ab-hero-inner {
    grid-template-columns: minmax(0, 1.06fr) minmax(0, 0.94fr);
    gap: 52px;
    align-items: end;
  }

  .page-about .ab-hero-copy h1 {
    font-size: clamp(42px, 4.6vw, 58px);
  }

  .page-about .ab-card {
    padding: 16px 14px 18px;
  }

  .page-about .ab-section {
    padding: 68px 0;
  }

  .page-about .ab-view-grid,
  .page-about .ab-desk-grid,
  .page-about .ab-dmqs-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .ab-desk-grid {
    grid-template-columns: minmax(0, 0.92fr) minmax(0, 1.08fr);
  }

  .page-about .ab-dmqs-grid {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    align-items: center;
  }

  .page-about .ab-head--wide {
    max-width: 70ch;
  }

  .page-about .ab-quote blockquote {
    max-width: 34ch;
  }

  .page-about .ab-cta-inner {
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 36px;
  }
}

@media (min-width: 1080px) {
  .page-about .ab-strip-grid {
    grid-template-columns: repeat(6, minmax(0, 1fr));
    gap: 18px;
  }

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

  .page-about .ab-engine-item {
    padding: 26px 20px;
  }

  .page-about .ab-toc-list a {
    padding: 16px 22px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-view-item,
  .page-about .ab-engine-item,
  .page-about .ab-toc-list a,
  .page-about .ab-road-item details,
  .page-about .ab-road-item::before {
    transition: none;
  }
}
<<<END>>>