.page-about {
  --ab-ink-soft: rgba(251, 250, 247, 0.72);
  --ab-ink-line: rgba(251, 250, 247, 0.16);
  background: var(--sand);
  color: var(--text);
  overflow-x: hidden;
}

/* ---------- hero ---------- */
.page-about .ab-hero {
  background: var(--ink-900);
  color: var(--paper);
  padding-block: clamp(20px, 3.4vw, 34px) clamp(36px, 5vw, 68px);
}

.page-about .ab-hero__inner {
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.page-about .crumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 10px;
  list-style: none;
  margin: 0 0 clamp(24px, 4vw, 44px);
  padding: 0;
  font-family: var(--label);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--ab-ink-soft);
}

.page-about .crumbs li + li::before {
  content: "/";
  margin-right: 10px;
  color: rgba(251, 250, 247, 0.34);
}

.page-about .crumbs a {
  color: var(--mint);
  text-decoration: none;
}

.page-about .crumbs a:hover {
  color: var(--signal-mist);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.page-about .ab-hero__grid {
  display: grid;
  gap: clamp(28px, 4vw, 52px);
}

.page-about .ab-kicker {
  font-family: var(--label);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--signal);
  margin: 0 0 14px;
}

.page-about h1 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(28px, 4.4vw, 54px);
  line-height: 1.24;
  letter-spacing: -0.01em;
  margin: 0 0 18px;
  max-width: 15em;
}

.page-about .ab-hero__lede {
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.8;
  color: var(--ab-ink-soft);
  margin: 0;
  max-width: 33em;
}

.page-about .ab-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 16px;
}

.page-about .ab-fact {
  border-top: 2px solid var(--signal);
  padding-top: 12px;
}

.page-about .ab-fact__label {
  font-family: var(--label);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--mint);
  margin: 0 0 6px;
}

.page-about .ab-fact__num {
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(26px, 3.2vw, 38px);
  line-height: 1.1;
  color: var(--paper);
  margin: 0 0 6px;
  font-variant-numeric: tabular-nums;
}

.page-about .ab-fact__desc {
  font-size: 13px;
  line-height: 1.6;
  color: rgba(251, 250, 247, 0.6);
  margin: 0;
}

/* ---------- layout ---------- */
.page-about .ab-layout {
  max-width: var(--wrap);
  margin-inline: auto;
  padding: clamp(28px, 4.4vw, 56px) var(--gutter) clamp(48px, 6vw, 92px);
  display: grid;
  gap: clamp(20px, 3vw, 44px);
}

/* ---------- index ---------- */
.page-about .ab-index__title {
  font-family: var(--label);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 10px;
}

.page-about .ab-index ol {
  list-style: none;
  margin: 0;
  padding: 0 0 4px;
  display: grid;
  gap: 8px;
  grid-auto-flow: column;
  grid-auto-columns: max-content;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .ab-index a {
  display: block;
  padding: 7px 14px;
  border: 1px solid var(--sand-deep);
  border-radius: 999px;
  background: var(--paper);
  font-family: var(--label);
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--ink-500);
  text-decoration: none;
  white-space: nowrap;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.page-about .ab-index a:hover {
  color: var(--ink-900);
  border-color: var(--signal);
  background: var(--signal-mist);
}

.page-about .ab-index a.is-active {
  background: var(--ink-900);
  border-color: var(--ink-900);
  color: var(--paper);
}

.page-about .ab-index a:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 3px;
}

/* ---------- chapter ---------- */
.page-about .ab-canvas {
  min-width: 0;
  display: grid;
  gap: clamp(16px, 2.4vw, 26px);
}

.page-about .ab-chapter {
  background: var(--paper);
  border-radius: var(--r-lg);
  padding: clamp(22px, 3.4vw, 44px);
  min-width: 0;
}

.page-about .ab-chapter--paper {
  background: var(--paper);
}

.page-about .ab-chapter--mint {
  background: var(--mint);
}

.page-about .ab-chapter--deep {
  background: var(--ink-900);
  color: var(--paper);
}

.page-about .ab-head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 12px 16px;
  align-items: start;
  border-top: 2px solid var(--signal);
  padding-top: 16px;
  margin-bottom: clamp(16px, 2.4vw, 24px);
}

.page-about .ab-idx {
  font-family: var(--label);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.18em;
  color: var(--signal);
  padding-top: 5px;
}

.page-about .ab-head h2 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(21px, 2.7vw, 33px);
  line-height: 1.34;
  letter-spacing: -0.01em;
  margin: 8px 0 0;
  max-width: 18em;
}

.page-about .ab-chapter--deep .ab-head h2 {
  color: var(--paper);
}

.page-about .ab-lede {
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.8;
  color: var(--ink-500);
  max-width: 34em;
  margin: 0 0 clamp(18px, 2.6vw, 26px);
}

.page-about .ab-chapter--deep .ab-lede {
  color: var(--ab-ink-soft);
}

.page-about .ab-chapter p,
.page-about .ab-chapter li {
  max-width: 34em;
}

.page-about .ab-chapter--deep .tag {
  background: rgba(251, 250, 247, 0.1);
  color: var(--mint);
}

/* ---------- plates ---------- */
.page-about .ab-plates {
  display: grid;
  gap: 14px;
}

.page-about .ab-plate {
  background: var(--sand);
  border-radius: var(--r-md);
  padding: 20px 20px 22px;
  transition: background 0.24s ease, transform 0.24s ease;
}

.page-about .ab-plate:hover {
  background: var(--signal-mist);
  transform: translateY(-2px);
}

.page-about .ab-plate:hover .tag {
  transform: translateY(-2px);
}

.page-about .ab-plate .tag {
  transition: transform 0.24s ease;
}

.page-about .ab-plate h3 {
  font-family: var(--sans);
  font-weight: 700;
  font-size: 16.5px;
  line-height: 1.5;
  margin: 12px 0 8px;
}

.page-about .ab-plate p {
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--ink-500);
  margin: 0;
}

/* ---------- steps ---------- */
.page-about .ab-steps {
  list-style: none;
  margin: 0 0 0 14px;
  padding: 0;
  border-left: 1px solid var(--sand-deep);
}

.page-about .ab-step {
  position: relative;
  padding: 0 0 clamp(18px, 2.4vw, 26px) 26px;
}

.page-about .ab-step:last-child {
  padding-bottom: 2px;
}

.page-about .ab-step__no {
  position: absolute;
  left: -15px;
  top: -2px;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: var(--ink-900);
  color: var(--paper);
  font-family: var(--label);
  font-size: 12px;
  font-weight: 700;
}

.page-about .ab-step:first-child .ab-step__no {
  background: var(--signal);
  color: #fff;
}

.page-about .ab-step h3 {
  font-family: var(--sans);
  font-weight: 700;
  font-size: 16px;
  line-height: 1.5;
  margin: 2px 0 6px;
}

.page-about .ab-step p {
  font-size: 14.5px;
  line-height: 1.78;
  color: var(--ink-500);
  margin: 0;
}

.page-about .ab-step details {
  margin-top: 10px;
}

.page-about .ab-step summary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 0;
  cursor: pointer;
  list-style: none;
  font-family: var(--label);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--signal-deep);
}

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

.page-about .ab-step summary::after {
  content: "+";
  font-size: 15px;
  line-height: 1;
}

.page-about .ab-step details[open] summary::after {
  content: "−";
}

.page-about .ab-step summary:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 3px;
}

.page-about .ab-step details ul {
  margin: 8px 0 0;
  padding-left: 18px;
  display: grid;
  gap: 5px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--ink-500);
}

/* ---------- figures ---------- */
.page-about .ab-figure {
  margin: clamp(20px, 3vw, 30px) 0 0;
}

.page-about .ab-figure img,
.page-about .ab-team__figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  border-radius: var(--r-md);
}

.page-about .media__caption {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.65;
  color: var(--muted);
  max-width: 40em;
}

/* ---------- era timeline ---------- */
.page-about .ab-era {
  list-style: none;
  margin: clamp(16px, 2.4vw, 24px) 0 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .ab-era__item {
  position: relative;
  padding: 16px 0 18px 22px;
  border-left: 2px solid var(--sand-deep);
  transition: border-color 0.24s ease;
}

.page-about .ab-era__item:hover {
  border-left-color: var(--signal);
}

.page-about .ab-era__year {
  display: block;
  font-family: var(--label);
  font-size: clamp(19px, 2.2vw, 26px);
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--ink-900);
  line-height: 1.1;
  margin-bottom: 6px;
}

.page-about .ab-era__item:hover .ab-era__year {
  color: var(--signal-deep);
}

.page-about .ab-era__item h3 {
  font-family: var(--sans);
  font-weight: 700;
  font-size: 14.5px;
  line-height: 1.5;
  margin: 0 0 6px;
}

.page-about .ab-era__item p {
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--ink-500);
  margin: 0;
}

/* ---------- team ---------- */
.page-about .ab-team {
  display: grid;
  gap: clamp(20px, 3vw, 30px);
}

.page-about .ab-roles {
  display: grid;
  gap: 16px;
  align-content: start;
}

.page-about .ab-role {
  border-top: 2px solid var(--ink-900);
  padding-top: 12px;
}

.page-about .ab-role h3 {
  font-family: var(--sans);
  font-weight: 700;
  font-size: 16px;
  line-height: 1.5;
  margin: 10px 0 6px;
}

.page-about .ab-role p {
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--ink-500);
  margin: 0;
}

.page-about .ab-team__figure {
  margin: 0;
  align-self: start;
}

.page-about .ab-note {
  margin: clamp(20px, 3vw, 28px) 0 0;
  padding-left: 16px;
  border-left: 2px solid var(--signal);
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--ink-500);
  max-width: 36em;
}

.page-about .ab-chapter--mint .ab-note {
  color: var(--ink-700);
}

/* ---------- region (dark) ---------- */
.page-about .ab-region {
  display: grid;
  gap: 20px;
  margin: clamp(18px, 2.6vw, 26px) 0 0;
}

.page-about .ab-region__num {
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(34px, 4.4vw, 52px);
  line-height: 1;
  color: var(--paper);
  margin: 0 0 10px;
  border-top: 2px solid var(--signal);
  padding-top: 14px;
}

.page-about .ab-region__num span {
  display: block;
  margin-top: 8px;
  font-family: var(--label);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--mint);
}

.page-about .ab-region__desc {
  font-size: 14px;
  line-height: 1.75;
  color: var(--ab-ink-soft);
  margin: 0;
}

.page-about .ab-deep-note {
  margin: clamp(20px, 3vw, 28px) 0 0;
  padding-top: 18px;
  border-top: 1px solid var(--ab-ink-line);
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--ab-ink-soft);
  max-width: 40em;
}

/* ---------- quality ---------- */
.page-about .ab-checks {
  list-style: none;
  margin: clamp(16px, 2.4vw, 24px) 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .ab-check {
  background: var(--sand);
  border-radius: var(--r-sm);
  padding: 16px 18px 18px;
}

.page-about .ab-check__no {
  font-family: var(--label);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--signal-deep);
  margin: 0 0 8px;
}

.page-about .ab-check h3 {
  font-family: var(--sans);
  font-weight: 700;
  font-size: 15.5px;
  margin: 0 0 6px;
}

.page-about .ab-check p:last-child {
  font-size: 14px;
  line-height: 1.75;
  color: var(--ink-500);
  margin: 0;
}

.page-about .ab-keep {
  margin-top: clamp(20px, 3vw, 28px);
  padding-left: 16px;
  border-left: 2px solid var(--signal);
}

.page-about .ab-keep > p:nth-of-type(2) {
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--ink-500);
  margin: 10px 0 16px;
}

/* ---------- principles ---------- */
.page-about .ab-claims {
  list-style: none;
  margin: clamp(16px, 2.4vw, 24px) 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .ab-claim {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 14px;
  align-items: start;
  padding-bottom: 14px;
  border-bottom: 1px solid rgba(14, 27, 42, 0.14);
}

.page-about .ab-claim:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .ab-claim__n {
  font-family: var(--label);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--ink-900);
  padding-top: 5px;
}

.page-about .ab-claim h3 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(17px, 1.9vw, 21px);
  line-height: 1.4;
  margin: 0 0 6px;
  color: var(--ink-900);
}

.page-about .ab-claim p {
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--ink-700);
  margin: 0;
}

.page-about .ab-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: clamp(22px, 3vw, 30px);
}

.page-about .ab-actions .btn {
  text-decoration: none;
}

.page-about .ab-actions .btn:focus-visible {
  outline: 2px solid var(--ink-900);
  outline-offset: 3px;
}

/* ---------- responsive ---------- */
@media (min-width: 720px) {
  .page-about .ab-region {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 24px;
  }

  .page-about .ab-checks {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
  }
}

@media (min-width: 760px) {
  .page-about .ab-plates {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .ab-plates > .ab-plate:nth-child(2) {
    margin-top: 22px;
  }

  .page-about .ab-roles {
    grid-template-columns: 1.15fr 0.9fr 1fr;
    gap: 18px;
  }
}

@media (min-width: 900px) {
  .page-about .ab-era {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    column-gap: 14px;
  }

  .page-about .ab-era__item {
    padding: 24px 6px 0 0;
    border-left: 0;
    border-top: 2px solid var(--sand-deep);
  }

  .page-about .ab-era__item:hover {
    border-left-color: transparent;
  }

  .page-about .ab-era__item::before {
    content: "";
    position: absolute;
    top: -7px;
    left: 0;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--sand-deep);
    transition: background 0.24s ease, transform 0.24s ease;
  }

  .page-about .ab-era__item:hover::before,
  .page-about .ab-era__item:focus-within::before {
    background: var(--signal);
    transform: scale(1.25);
  }

  .page-about .ab-era__item:hover {
    border-top-color: var(--signal);
  }
}

@media (min-width: 940px) {
  .page-about .ab-layout {
    grid-template-columns: 172px minmax(0, 1fr);
    align-items: start;
  }

  .page-about .ab-index {
    position: sticky;
    top: calc(var(--header-h) + 28px);
  }

  .page-about .ab-index ol {
    grid-auto-flow: row;
    grid-auto-columns: auto;
    overflow: visible;
    gap: 2px;
    padding-bottom: 0;
  }

  .page-about .ab-index a {
    padding: 7px 4px 7px 12px;
    border: 0;
    border-left: 2px solid var(--sand-deep);
    border-radius: 0;
    background: transparent;
    font-size: 13px;
    letter-spacing: 0;
    white-space: normal;
  }

  .page-about .ab-index a:hover {
    background: transparent;
    border-left-color: var(--signal);
    color: var(--ink-900);
  }

  .page-about .ab-index a.is-active {
    background: transparent;
    border-left-color: var(--signal);
    color: var(--ink-900);
    font-weight: 700;
  }
}

@media (min-width: 1000px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: end;
  }

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

@media (min-width: 1020px) {
  .page-about .ab-team {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
    align-items: start;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-plate,
  .page-about .ab-plate .tag,
  .page-about .ab-era__item::before {
    transition: none;
  }

  .page-about .ab-plate:hover {
    transform: none;
  }

  .page-about .ab-plate:hover .tag {
    transform: none;
  }
}
<<<END>>>