.page-about {
  --ab-line: var(--line-500);
  background: var(--ink-950);
  color: var(--smoke-100);
  font-family: var(--sans);
}

.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  padding-bottom: clamp(36px, 6vw, 76px);
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  top: -12%;
  right: -14%;
  width: min(660px, 76vw);
  height: min(660px, 76vw);
  background: var(--amber-450);
  opacity: 0.08;
  transform: rotate(16deg);
  clip-path: polygon(0 0, 100% 0, 100% 58%, 0 100%);
  pointer-events: none;
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: clamp(90px, 18vw, 220px);
  height: 3px;
  background: var(--cinnabar-500);
  pointer-events: none;
}

.page-about .ab-hero__inner {
  position: relative;
  z-index: 1;
  padding-top: clamp(18px, 3vw, 32px);
}

.page-about .breadcrumb {
  margin-bottom: clamp(22px, 4vw, 40px);
}

.page-about .breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  gap: 0 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: 13px;
  line-height: 1.6;
}

.page-about .breadcrumb__item {
  display: inline-flex;
  align-items: center;
}

.page-about .breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  margin-right: 8px;
  color: var(--ab-line);
}

.page-about .crumb {
  color: var(--smoke-400);
  text-decoration: none;
  transition: color var(--dur) var(--ease);
}

.page-about a.crumb:hover,
.page-about a.crumb:focus-visible {
  color: var(--amber-450);
}

.page-about .crumb[aria-current="page"] {
  color: var(--smoke-100);
}

.page-about .ab-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 52px);
  align-items: end;
}

.page-about .ab-hero h1 {
  margin: 14px 0 0;
  max-width: 22ch;
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(30px, 5.2vw, 54px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--smoke-100);
}

.page-about .ab-hero__lede {
  margin-top: clamp(18px, 2.4vw, 26px);
  max-width: 54ch;
  font-size: clamp(15px, 1.3vw, 17px);
  line-height: 1.85;
  color: var(--smoke-100);
}

.page-about .ab-hero__jump {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 18px;
  margin-top: clamp(22px, 3vw, 32px);
  padding-top: 16px;
  border-top: 1px dashed var(--ab-line);
}

.page-about .ab-hero__jumplabel {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--celadon-400);
}

.page-about .ab-jump {
  font-size: 14px;
  color: var(--smoke-400);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .ab-jump:hover,
.page-about .ab-jump:focus-visible {
  color: var(--amber-200);
  border-bottom-color: var(--amber-200);
}

.page-about .ab-plate {
  padding: clamp(20px, 3vw, 30px);
  border: 1px solid var(--ab-line);
  background: linear-gradient(158deg, var(--ink-850) 0%, var(--ink-950) 78%);
  box-shadow: 0 24px 48px -34px rgba(0, 0, 0, 0.95);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 26px), calc(100% - 26px) 100%, 0 100%);
}

.page-about .ab-plate__label {
  display: block;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--smoke-400);
}

.page-about .ab-plate__ver {
  display: block;
  margin-top: 8px;
  font-family: var(--mono);
  font-size: clamp(44px, 7.5vw, 68px);
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--amber-450);
}

.page-about .ab-plate__text {
  margin: 14px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--smoke-400);
}

.page-about .ab-plate__link {
  display: inline-block;
  margin-top: 18px;
  font-family: var(--mono);
  font-size: 13px;
  color: var(--amber-200);
  text-decoration: none;
  border-bottom: 1px solid var(--ab-line);
  padding-bottom: 2px;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .ab-plate__link:hover,
.page-about .ab-plate__link:focus-visible {
  color: var(--amber-450);
  border-bottom-color: var(--amber-450);
}

.page-about .ab-section {
  padding: clamp(38px, 6vw, 76px) 0;
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-section--panel {
  background: var(--ink-850);
}

.page-about .ab-cols {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 40px);
}

.page-about .ab-aside__num {
  display: block;
  font-size: clamp(26px, 3.6vw, 38px);
  line-height: 1;
  letter-spacing: 0.08em;
  color: var(--celadon-400);
}

.page-about .ab-aside h2 {
  margin: 12px 0 0;
  font-family: var(--serif);
  font-weight: 500;
  font-size: clamp(21px, 2.6vw, 30px);
  line-height: 1.38;
  color: var(--smoke-100);
}

.page-about .ab-note {
  margin: 12px 0 0;
  max-width: 46ch;
  font-size: 14px;
  line-height: 1.8;
  color: var(--smoke-400);
}

.page-about .ab-text {
  margin: 0 0 18px;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--smoke-100);
}

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

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

.page-about .ab-ledger {
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--ab-line);
}

.page-about .ab-ledger__row {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 6px 14px;
  align-items: baseline;
  padding: 16px 0;
  border-bottom: 1px solid var(--ab-line);
  transition: background var(--dur) var(--ease);
}

.page-about .ab-ledger__row:hover {
  background: rgba(16, 40, 61, 0.55);
}

.page-about .ab-ledger__letter {
  font-size: 17px;
  color: var(--celadon-400);
  letter-spacing: 0.06em;
  transition: color var(--dur) var(--ease);
}

.page-about .ab-ledger__row:hover .ab-ledger__letter {
  color: var(--amber-450);
}

.page-about .ab-ledger__title {
  margin: 0;
  font-family: var(--serif);
  font-weight: 500;
  font-size: 17px;
  line-height: 1.5;
  color: var(--smoke-100);
}

.page-about .ab-ledger__text {
  margin: 6px 0 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--smoke-400);
}

.page-about .ab-ledger__go {
  grid-column: 2;
  justify-self: start;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--amber-200);
  text-decoration: none;
  border-bottom: 1px solid var(--ab-line);
  padding-bottom: 2px;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .ab-ledger__go:hover,
.page-about .ab-ledger__go:focus-visible {
  color: var(--amber-450);
  border-bottom-color: var(--amber-450);
}

.page-about .ab-figures {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: 30px;
  background: var(--ab-line);
  border: 1px solid var(--ab-line);
}

.page-about .ab-figure {
  padding: 18px 16px;
  background: var(--ink-950);
}

.page-about .ab-figure__num {
  display: block;
  font-size: clamp(26px, 3.4vw, 36px);
  line-height: 1;
  color: var(--smoke-100);
}

.page-about .ab-figure__label {
  display: block;
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.5;
  color: var(--smoke-400);
}

.page-about .ab-head {
  margin-bottom: clamp(24px, 3.6vw, 40px);
}

.page-about .ab-head h2 {
  margin: 12px 0 0;
  max-width: 28ch;
  font-family: var(--serif);
  font-weight: 500;
  font-size: clamp(22px, 3vw, 34px);
  line-height: 1.34;
  color: var(--smoke-100);
}

.page-about .ab-timeline {
  position: relative;
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
}

.page-about .ab-node {
  position: relative;
  padding: 4px 0 26px 24px;
  border-left: 1px solid var(--ab-line);
}

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

.page-about .ab-node::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 8px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink-950);
  border: 1px solid var(--amber-450);
}

.page-about .ab-node__year {
  display: block;
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--amber-450);
}

.page-about .ab-node__title {
  margin: 8px 0 0;
  font-family: var(--serif);
  font-weight: 500;
  font-size: 18px;
  line-height: 1.5;
  color: var(--smoke-100);
}

.page-about .ab-node__text {
  margin: 8px 0 0;
  max-width: 34ch;
  font-size: 14px;
  line-height: 1.8;
  color: var(--smoke-400);
}

.page-about .ab-node__extra {
  margin: 10px 0 0;
  padding-left: 10px;
  max-width: 34ch;
  font-size: 13px;
  line-height: 1.75;
  color: var(--smoke-400);
  border-left: 2px solid var(--cinnabar-500);
}

.page-about .ab-figure-frame {
  margin: clamp(28px, 4vw, 46px) 0 0;
}

.page-about .ab-figure-frame img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

.page-about .ab-steps {
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--ab-line);
}

.page-about .ab-step {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 12px;
  padding: 16px 0;
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-step__num {
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--celadon-400);
  padding-top: 3px;
}

.page-about .ab-step__title {
  margin: 0;
  font-family: var(--serif);
  font-weight: 500;
  font-size: 17px;
  line-height: 1.5;
  color: var(--smoke-100);
}

.page-about .ab-step__text {
  margin: 6px 0 0;
  max-width: 52ch;
  font-size: 14px;
  line-height: 1.8;
  color: var(--smoke-400);
}

.page-about .ab-reach {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 3.4vw, 44px);
  align-items: start;
}

.page-about .ab-reach__figure {
  margin: 0;
}

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

.page-about .ab-stats {
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--ab-line);
}

.page-about .ab-stat {
  display: grid;
  grid-template-columns: minmax(84px, auto) minmax(0, 1fr);
  gap: 16px;
  align-items: baseline;
  padding: 16px 0;
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-stat__num {
  font-size: clamp(30px, 4.4vw, 44px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--amber-450);
}

.page-about .ab-stat__unit {
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--smoke-400);
  margin-left: 4px;
}

.page-about .ab-stat__body {
  display: block;
}

.page-about .ab-stat__label {
  display: block;
  font-family: var(--serif);
  font-weight: 500;
  font-size: 15px;
  line-height: 1.5;
  color: var(--smoke-100);
}

.page-about .ab-stat__note {
  display: block;
  margin-top: 4px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--smoke-400);
}

.page-about .ab-reach__body .ab-note {
  margin-top: 20px;
  max-width: 52ch;
}

.page-about .ab-tools {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 24px 0;
  background: var(--ab-line);
  border: 1px solid var(--ab-line);
}

.page-about .ab-tool {
  padding: 20px 18px;
  background: var(--ink-950);
  transition: background var(--dur) var(--ease);
}

.page-about .ab-tool:hover {
  background: var(--ink-850);
}

.page-about .ab-tool__idx {
  display: block;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--celadon-400);
}

.page-about .ab-tool__title {
  margin: 10px 0 0;
  font-family: var(--serif);
  font-weight: 500;
  font-size: 17px;
  line-height: 1.5;
  color: var(--smoke-100);
}

.page-about .ab-tool__text {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--smoke-400);
}

.page-about .ab-cta {
  border-bottom: 0;
}

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

.page-about .ab-cta__item a {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 18px 20px;
  background: var(--ink-850);
  color: var(--smoke-100);
  text-decoration: none;
  font-size: 15px;
  line-height: 1.6;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .ab-cta__item a:hover,
.page-about .ab-cta__item a:focus-visible {
  background: var(--ink-800);
  color: var(--amber-200);
}

.page-about .ab-cta__idx {
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--celadon-400);
}

.page-about .ab-cta__item a:hover .ab-cta__idx {
  color: var(--amber-450);
}

@media (min-width: 720px) {
  .page-about .ab-ledger__row {
    grid-template-columns: 52px minmax(0, 1fr) auto;
    align-items: start;
  }

  .page-about .ab-ledger__go {
    grid-column: 3;
    justify-self: end;
    margin-top: 2px;
  }

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

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

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

@media (min-width: 900px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: clamp(28px, 4vw, 56px);
  }

  .page-about .ab-cols {
    grid-template-columns: minmax(0, 3fr) minmax(0, 9fr);
    gap: clamp(28px, 4vw, 60px);
    align-items: start;
  }

  .page-about .ab-aside {
    position: sticky;
    top: calc(var(--bar-h) + 24px);
    align-self: start;
  }

  .page-about .ab-timeline {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0 24px;
    padding-top: 30px;
  }

  .page-about .ab-timeline::before {
    content: "";
    position: absolute;
    left: 0;
    right: 0;
    top: 10px;
    height: 1px;
    background: linear-gradient(90deg, var(--ab-line) 0%, var(--amber-450) 52%, var(--celadon-400) 100%);
  }

  .page-about .ab-node {
    padding: 0;
    border-left: 0;
  }

  .page-about .ab-node::before {
    left: 0;
    top: -25px;
  }

  .page-about .ab-node__text,
  .page-about .ab-node__extra {
    max-width: 30ch;
  }

  .page-about .ab-reach {
    grid-template-columns: minmax(0, 4fr) minmax(0, 6fr);
    gap: clamp(28px, 4vw, 56px);
  }

  .page-about .ab-head h2 {
    max-width: 32ch;
  }
}

@media (hover: hover) and (min-width: 900px) {
  .page-about .ab-node__extra {
    max-height: 0;
    margin-top: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height var(--dur) var(--ease), opacity var(--dur) var(--ease), margin-top var(--dur) var(--ease);
  }

  .page-about .ab-node:hover .ab-node__extra,
  .page-about .ab-node:focus-within .ab-node__extra {
    max-height: 240px;
    margin-top: 10px;
    opacity: 1;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-node__extra,
  .page-about .ab-ledger__row,
  .page-about .ab-tool,
  .page-about .ab-cta__item a,
  .page-about .crumb,
  .page-about .ab-jump {
    transition: none;
  }
}
<<<END>>>