.page-about {
  --about-stats-bg: #FFC107;
  --about-updates-bg: #00A5CF;
  --about-timeline-line: rgba(30, 30, 30, 0.2);
  background: var(--c-warm-white);
  color: var(--c-ink);
  font-family: var(--font-body);
  line-height: 1.6;
}

.page-about .about-crumb {
  padding-top: 18px;
}

.page-about .about-hero,
.page-about .about-stats,
.page-about .about-taxonomy,
.page-about .about-updates,
.page-about .about-search {
  padding: 52px 0 56px;
}

.page-about .about-hero__grid {
  display: grid;
  gap: 28px;
  align-items: start;
}

.page-about .about-toc {
  background: var(--c-charcoal);
  color: var(--c-warm-white);
  border-radius: var(--radius);
  padding: 26px 20px 18px;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.page-about .about-toc::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 6px;
  background: linear-gradient(90deg, var(--c-neon) 0 40%, var(--c-buffer) 40% 70%, var(--c-error) 70% 100%);
}

.page-about .about-toc__label {
  display: block;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--c-amber);
  margin-bottom: 14px;
}

.page-about .about-toc__list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-toc__item + .about-toc__item {
  border-top: 1px solid rgba(255, 248, 240, 0.12);
}

.page-about .about-toc__link {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 11px 8px;
  color: var(--c-warm-white);
  text-decoration: none;
  font-size: 15px;
  border-left: 3px solid transparent;
  transition: border-color 0.2s, background 0.2s;
}

.page-about .about-toc__link:hover,
.page-about .about-toc__link:focus {
  border-left-color: var(--c-neon);
  background: rgba(57, 255, 20, 0.08);
}

.page-about .about-toc__num {
  color: var(--c-amber);
  font-size: 13px;
}

.page-about .about-toc__foot {
  margin-top: 20px;
  padding-top: 14px;
  border-top: 1px solid rgba(255, 248, 240, 0.12);
  display: flex;
  justify-content: space-between;
  gap: 8px;
}

.page-about .about-toc__version,
.page-about .about-toc__freq {
  font-size: 12px;
  color: rgba(255, 248, 240, 0.7);
}

.page-about .about-hero__main {
  position: relative;
  background: var(--c-warm-white);
  border: 1px solid rgba(45, 45, 45, 0.08);
  border-radius: var(--radius);
  padding: 32px 24px;
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}

.page-about .about-hero__main::before {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 150px;
  height: 150px;
  background: var(--c-amber);
  opacity: 0.16;
  clip-path: polygon(0 0, 100% 0, 100% 100%);
  pointer-events: none;
}

.page-about .about-hero__eyebrow {
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--c-peacock);
  margin: 0 0 8px;
}

.page-about .about-hero h1 {
  font-family: var(--font-headline);
  font-size: clamp(24px, 3vw, 36px);
  line-height: 1.12;
  margin: 0 0 18px;
  letter-spacing: 0.01em;
  max-width: 22ch;
}

.page-about .about-hero__lede {
  font-size: 16px;
  line-height: 1.8;
  margin: 0 0 26px;
  max-width: 58ch;
}

.page-about .about-hero__lede strong {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--c-coral);
}

.page-about .about-lede__keyword {
  font-family: var(--font-body);
  color: var(--c-ink);
  border-bottom: 3px solid var(--c-amber);
  padding-bottom: 1px;
}

.page-about .about-hero__figure {
  margin: 0;
  border: 1px solid rgba(45, 45, 45, 0.08);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--c-warm-white);
}

.page-about .about-hero__figure img {
  display: block;
  width: 100%;
  height: auto;
}

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

.page-about .section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 14px;
  margin-bottom: 10px;
  padding-bottom: 14px;
  border-bottom: 2px solid rgba(45, 45, 45, 0.1);
}

.page-about .section-head__idx {
  font-size: 14px;
  font-weight: 700;
  color: var(--c-coral);
}

.page-about .section-head__title {
  font-family: var(--font-headline);
  font-size: clamp(22px, 2.4vw, 30px);
  line-height: 1.1;
  margin: 0;
}

.page-about .section-head__meta {
  font-size: 13px;
  opacity: 0.65;
  margin-left: auto;
}

.page-about .about-stats {
  background: var(--about-stats-bg);
  color: var(--c-ink);
}

.page-about .about-stats .section-head__meta {
  color: rgba(45, 45, 45, 0.72);
}

.page-about .stat-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  margin-top: 24px;
}

.page-about .stat-card {
  border-radius: var(--radius);
  padding: 22px 18px;
  color: #fff;
  box-shadow: var(--shadow-sm);
  position: relative;
  overflow: hidden;
  min-height: 178px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: transform 0.2s, box-shadow 0.2s;
}

.page-about .stat-card:hover,
.page-about .stat-card:focus-within {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.page-about .stat-card::after {
  content: "";
  position: absolute;
  right: -28px;
  bottom: -28px;
  width: 84px;
  height: 84px;
  border: 2px solid rgba(255, 255, 255, 0.28);
  border-radius: 50%;
  pointer-events: none;
}

.page-about .stat-card--coral {
  background: var(--c-coral);
}

.page-about .stat-card--teal {
  background: var(--c-teal);
}

.page-about .stat-card--violet {
  background: var(--c-violet);
}

.page-about .stat-card--peacock {
  background: var(--c-peacock);
}

.page-about .stat-card__label {
  display: block;
  font-size: 12px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  opacity: 0.92;
}

.page-about .stat-card__num {
  display: block;
  font-family: var(--font-headline);
  font-size: 36px;
  line-height: 1.05;
  margin: 10px 0 4px;
}

.page-about .stat-card__unit {
  font-size: 14px;
  opacity: 0.9;
}

.page-about .stat-card__detail {
  font-size: 13px;
  line-height: 1.55;
  opacity: 0.95;
  margin: 12px 0 0;
  border-top: 1px solid rgba(255, 255, 255, 0.28);
  padding-top: 9px;
  position: relative;
  z-index: 1;
}

.page-about .taxonomy-grid {
  display: grid;
  gap: 26px;
  margin-top: 24px;
  align-items: start;
}

.page-about .tree {
  background: var(--c-warm-white);
  border: 1px solid rgba(45, 45, 45, 0.08);
  border-radius: var(--radius);
  padding: 22px 16px 14px;
  box-shadow: var(--shadow-sm);
}

.page-about .tree-root {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-headline);
  font-size: 20px;
  padding-bottom: 10px;
  border-bottom: 2px dashed var(--c-peacock);
}

.page-about .tree-root__mark {
  width: 12px;
  height: 12px;
  background: var(--c-peacock);
  transform: rotate(45deg);
  flex-shrink: 0;
}

.page-about .tree-list {
  list-style: none;
  margin: 0;
  padding: 4px 0 0;
}

.page-about .tree-row {
  display: grid;
  grid-template-columns: 36px 1fr;
  gap: 10px;
  align-items: stretch;
}

.page-about .tree-row__svg {
  width: 36px;
  height: 100%;
  min-height: 48px;
  display: block;
}

.page-about .tree-row__body {
  padding: 12px 0;
  border-bottom: 1px solid rgba(45, 45, 45, 0.06);
}

.page-about .tree-row--last .tree-row__body {
  border-bottom: 0;
}

.page-about .tree-row__cat {
  font-family: var(--font-headline);
  font-size: 17px;
  color: var(--c-charcoal);
  margin-right: 10px;
}

.page-about .tree-row__channels {
  font-size: 14px;
  color: var(--c-ink);
  opacity: 0.72;
  margin-right: 8px;
}

.page-about .tree-row__tags {
  font-size: 12px;
  margin: 0 2px 2px 0;
  vertical-align: middle;
}

.page-about .taxonomy-figure {
  margin: 0;
  border: 1px solid rgba(45, 45, 45, 0.08);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--c-amber);
  box-shadow: var(--shadow-sm);
}

.page-about .taxonomy-figure img {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .about-updates {
  background: var(--about-updates-bg);
  color: var(--c-ink);
}

.page-about .about-updates .section-head__idx,
.page-about .about-updates .section-head__title,
.page-about .about-updates .section-head__meta {
  color: var(--c-ink);
}

.page-about .about-updates .section-head__meta {
  opacity: 0.72;
}

.page-about .updates-grid {
  display: grid;
  gap: 26px;
  margin-top: 24px;
  align-items: center;
}

.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .timeline-item {
  position: relative;
  padding: 0 0 28px 28px;
}

.page-about .timeline-item:last-child {
  padding-bottom: 0;
}

.page-about .timeline-item::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 4px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--c-amber);
  border: 3px solid var(--c-warm-white);
  box-shadow: 0 0 0 2px var(--c-charcoal);
}

.page-about .timeline-item:not(:last-child)::after {
  content: "";
  position: absolute;
  left: 10px;
  top: 26px;
  bottom: -6px;
  width: 2px;
  background: var(--about-timeline-line);
}

.page-about .timeline-item__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 14px;
}

.page-about .timeline-batch {
  font-size: 17px;
  font-weight: 700;
  color: var(--c-charcoal);
}

.page-about .timeline-date {
  font-size: 12px;
  color: rgba(30, 30, 30, 0.6);
}

.page-about .timeline-item__desc {
  margin: 8px 0 0;
  font-size: 15px;
  line-height: 1.7;
  max-width: 52ch;
  color: rgba(30, 30, 30, 0.82);
}

.page-about .updates-figure {
  margin: 0;
  border: 1px solid rgba(45, 45, 45, 0.08);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--c-charcoal);
  box-shadow: var(--shadow-sm);
}

.page-about .updates-figure img {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .updates-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 24px;
  margin-top: 24px;
  padding: 14px 18px;
  background: rgba(255, 248, 240, 0.34);
  border-radius: var(--radius-sm);
}

.page-about .updates-meta__item {
  font-size: 13px;
  color: var(--c-charcoal);
}

.page-about .search-steps {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
}

.page-about .search-step {
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 16px;
  padding: 20px 0;
  border-bottom: 1px solid rgba(45, 45, 45, 0.1);
  align-items: center;
}

.page-about .search-step:last-child {
  border-bottom: 0;
}

.page-about .search-step__num {
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: var(--c-charcoal);
  color: var(--c-neon);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  font-weight: 700;
}

.page-about .search-step__body h3 {
  font-size: 18px;
  margin: 0 0 4px;
}

.page-about .search-step__body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.65;
  opacity: 0.78;
  max-width: 56ch;
}

.page-about .search-step .btn {
  grid-column: 2;
  justify-self: start;
  margin-top: 6px;
}

.page-about .search-guide {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px 22px;
  margin-top: 26px;
  padding: 20px 24px;
  background: var(--c-charcoal);
  color: var(--c-warm-white);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}

.page-about .search-guide__btn {
  flex-shrink: 0;
}

.page-about .search-guide__note {
  font-size: 14px;
  opacity: 0.8;
}

.page-about .about-links {
  padding: 8px 0 72px;
}

.page-about .about-links__grid {
  display: grid;
  gap: 16px;
}

.page-about .about-links__card {
  display: block;
  background: var(--c-warm-white);
  border: 1px solid rgba(45, 45, 45, 0.1);
  border-top: 4px solid var(--c-peacock);
  border-radius: var(--radius);
  padding: 24px;
  text-decoration: none;
  color: var(--c-ink);
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
}

.page-about .about-links__card:nth-child(2) {
  border-top-color: var(--c-coral);
}

.page-about .about-links__card:nth-child(3) {
  border-top-color: var(--c-violet);
}

.page-about .about-links__card:hover,
.page-about .about-links__card:focus {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--c-peacock);
}

.page-about .about-links__label {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--c-coral);
}

.page-about .about-links__title {
  display: block;
  font-family: var(--font-headline);
  font-size: 22px;
  margin: 6px 0;
}

.page-about .about-links__desc {
  font-size: 14px;
  opacity: 0.72;
}

@media (hover: hover) {
  .page-about .stat-card__detail {
    opacity: 0;
    transform: translateY(4px);
    transition: opacity 0.25s, transform 0.25s;
  }

  .page-about .stat-card:hover .stat-card__detail,
  .page-about .stat-card:focus-within .stat-card__detail {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (min-width: 640px) {
  .page-about .stat-card__num {
    font-size: 44px;
  }

  .page-about .search-step {
    grid-template-columns: 48px 1fr auto;
  }

  .page-about .search-step .btn {
    grid-column: 3;
    margin-top: 0;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero,
  .page-about .about-stats,
  .page-about .about-taxonomy,
  .page-about .about-updates,
  .page-about .about-search {
    padding: 68px 0 76px;
  }

  .page-about .about-hero__grid {
    grid-template-columns: 260px 1fr;
    gap: 32px;
  }

  .page-about .about-toc {
    position: sticky;
    top: 24px;
  }

  .page-about .about-hero__main {
    display: grid;
    grid-template-columns: 1.15fr 0.85fr;
    column-gap: 32px;
    align-items: center;
  }

  .page-about .about-hero__eyebrow {
    grid-column: 1;
    grid-row: 1;
  }

  .page-about .about-hero h1 {
    grid-column: 1;
    grid-row: 2;
  }

  .page-about .about-hero__lede {
    grid-column: 1;
    grid-row: 3;
  }

  .page-about .about-hero__figure {
    grid-column: 2;
    grid-row: 1 / span 3;
    margin: 0;
  }

  .page-about .stat-grid {
    grid-template-columns: repeat(4, 1fr);
    gap: 18px;
  }

  .page-about .taxonomy-grid {
    grid-template-columns: 1.05fr 0.95fr;
    gap: 32px;
  }

  .page-about .updates-grid {
    grid-template-columns: 1.05fr 0.95fr;
    gap: 32px;
  }

  .page-about .about-links__grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
  }

  .page-about .about-links__card {
    padding: 28px;
  }
}