.page-about {
  --about-shadow-hard: 6px 6px 0 rgba(26, 26, 26, 0.9);
  --about-shadow-soft: 4px 4px 0 rgba(26, 26, 26, 0.15);
  background: var(--bg-warm);
  overflow-x: clip;
}

.page-about .container {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: 20px;
}

.page-about .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding-top: 24px;
  padding-bottom: 4px;
  font-size: 14px;
  color: var(--gray);
}

.page-about .breadcrumb a {
  color: var(--accent-blue-dark);
  text-decoration: none;
  border-bottom: 1px solid rgba(0, 105, 146, 0.4);
}

.page-about .breadcrumb a:hover {
  color: var(--ink);
  border-bottom-color: var(--ink);
}

.page-about .breadcrumb__current {
  color: var(--ink);
  font-weight: 600;
}

.page-about .about-hero {
  padding: 32px 0 44px;
  border-bottom: 4px solid var(--ink);
}

.page-about .about-hero__kicker {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--accent);
}

.page-about .about-hero h1 {
  margin: 0 0 16px;
  font-family: var(--font-heading);
  font-size: clamp(32px, 6vw, 56px);
  font-weight: 600;
  line-height: 1.15;
  max-width: 13em;
}

.page-about .about-hero__lead {
  margin: 0;
  max-width: 48em;
  font-size: 17px;
  line-height: 1.7;
  color: var(--gray);
}

.page-about .about-hero__lead strong {
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 0.9em;
}

.page-about .about-hero__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .block-head {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 28px;
  padding-bottom: 20px;
  border-bottom: 2px solid var(--ink);
}

.page-about .block-head__text {
  min-width: 0;
}

.page-about .block-head__text .section-title {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: clamp(24px, 3vw, 34px);
  line-height: 1.2;
}

.page-about .block-head__desc {
  margin: 6px 0 0;
  color: var(--gray);
  font-size: 15px;
}

.page-about .section-no {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  min-width: 44px;
  height: 44px;
  padding: 0 10px;
  border: 2px solid var(--ink);
  background: var(--card-white);
  font-family: var(--font-mono);
  font-size: 18px;
  font-weight: 700;
}

.page-about .stat-panel {
  padding-block: 48px;
}

.page-about .stat-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.page-about .stat-card {
  position: relative;
  display: flex;
  flex-direction: column;
  min-height: 128px;
  padding: 20px;
  border: 2px solid var(--ink);
  box-shadow: var(--about-shadow-hard);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.page-about .stat-card__label {
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: rgba(0, 0, 0, 0.72);
}

.page-about .stat-card__num {
  margin-top: 8px;
  font-family: var(--font-mono);
  font-size: clamp(26px, 7vw, 38px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.page-about .stat-card__extra {
  display: none;
  position: absolute;
  top: 100%;
  left: 8px;
  right: 8px;
  z-index: 10;
  margin-top: 4px;
  padding: 9px 11px;
  background: var(--ink);
  color: #fff;
  border: 2px solid var(--ink);
  box-shadow: 4px 4px 0 rgba(0, 0, 0, 0.25);
  font-size: 12px;
  line-height: 1.45;
}

.page-about .stat-card--ink {
  background: var(--ink);
  color: #fff;
}

.page-about .stat-card--ink .stat-card__label {
  color: rgba(255, 255, 255, 0.72);
}

.page-about .stat-card--blue {
  background: var(--accent-blue);
  color: var(--ink);
}

.page-about .stat-card--teal {
  background: var(--tag-teal);
  color: #fff;
}

.page-about .stat-card--yellow {
  background: var(--tag-yellow);
  color: var(--ink);
}

.page-about .stat-card--purple {
  background: var(--tag-purple);
  color: #fff;
}

.page-about .stat-card--coral {
  background: var(--tag-coral);
  color: #fff;
}

.page-about .stat-card--teal .stat-card__label,
.page-about .stat-card--purple .stat-card__label,
.page-about .stat-card--coral .stat-card__label {
  color: rgba(255, 255, 255, 0.82);
}

.page-about .stat-figure {
  margin: 34px 0 0;
  padding: 10px;
  border: 2px solid var(--ink);
  background: var(--card-white);
  box-shadow: 8px 8px 0 rgba(26, 26, 26, 0.18);
}

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

.page-about .scope-panel {
  padding-block: 48px;
}

.page-about .scope-split {
  display: grid;
  gap: 24px;
}

.page-about .scope-block {
  position: relative;
  padding: 24px;
  border: 2px solid var(--ink);
  background: var(--card-white);
  box-shadow: var(--about-shadow-soft);
}

.page-about .scope-block--include {
  border-top: 8px solid var(--tag-teal);
}

.page-about .scope-block--exclude {
  border-top: 8px solid var(--tag-coral);
}

.page-about .scope-block__title {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 18px;
  font-size: 21px;
  font-family: var(--font-heading);
  font-weight: 800;
}

.page-about .scope-block__title::before {
  content: "";
  width: 16px;
  height: 16px;
  border: 2px solid var(--ink);
  background: var(--tag-teal);
}

.page-about .scope-block--exclude .scope-block__title::before {
  background: var(--tag-coral);
}

.page-about .scope-list {
  display: grid;
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .scope-list li {
  display: flex;
  align-items: baseline;
  gap: 10px;
  font-size: 15px;
  line-height: 1.6;
}

.page-about .scope-list__mark {
  flex-shrink: 0;
  font-family: var(--font-mono);
  font-size: 17px;
  font-weight: 700;
  color: var(--tag-teal);
}

.page-about .scope-block--exclude .scope-list__mark {
  color: var(--tag-coral);
}

.page-about .scope-list code {
  padding: 1px 5px;
  border: 1px solid rgba(26, 26, 26, 0.25);
  background: var(--bg-warm);
  font-family: var(--font-mono);
  font-size: 0.9em;
}

.page-about .taxonomy-panel {
  padding-block: 48px;
}

.page-about .taxonomy-layout {
  display: grid;
  gap: 32px;
}

.page-about .taxonomy-tree__label {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin: 0 0 18px;
}

.page-about .taxonomy-tree__arrow {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 700;
  color: var(--accent);
}

.page-about .index-num {
  display: inline-block;
  padding: 4px 8px;
  border: 2px solid var(--ink);
  background: var(--card-white);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
}

.page-about .taxonomy-cats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

.page-about .taxonomy-cat {
  border: 2px solid var(--ink);
  background: var(--card-white);
  box-shadow: var(--about-shadow-soft);
}

.page-about .taxonomy-cat--coral {
  border-top: 6px solid var(--tag-coral);
}

.page-about .taxonomy-cat--purple {
  border-top: 6px solid var(--tag-purple);
}

.page-about .taxonomy-cat--teal {
  border-top: 6px solid var(--tag-teal);
}

.page-about .taxonomy-cat--yellow {
  border-top: 6px solid var(--tag-yellow);
}

.page-about .taxonomy-cat summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 13px 14px;
  list-style: none;
  cursor: pointer;
}

.page-about .taxonomy-cat summary::-webkit-details-marker {
  display: none;
}

.page-about .taxonomy-cat__name {
  font-size: 16px;
  font-weight: 700;
}

.page-about .taxonomy-cat__count {
  padding: 2px 6px;
  background: var(--ink);
  color: #fff;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
}

.page-about .taxonomy-cat__plus {
  width: 24px;
  height: 24px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 2px solid var(--ink);
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
}

.page-about .taxonomy-cat__plus::before {
  content: "＋";
}

.page-about .taxonomy-cat[open] .taxonomy-cat__plus::before {
  content: "－";
}

.page-about .taxonomy-cat__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  padding: 12px 14px 14px;
  border-top: 1px dashed var(--ink);
}

.page-about .taxonomy-figure {
  align-self: start;
  margin: 0;
  padding: 10px;
  border: 2px solid var(--ink);
  background: var(--card-white);
  box-shadow: var(--about-shadow-soft);
}

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

.page-about .taxonomy-figure figcaption {
  padding: 10px 6px 4px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--gray);
}

.page-about .taxonomy-rule {
  margin: 32px 0 0;
  padding: 18px 20px;
  border: 2px solid var(--ink);
  background: var(--card-white);
  box-shadow: var(--about-shadow-soft);
  font-size: 15px;
  line-height: 1.7;
}

.page-about .taxonomy-rule a {
  color: var(--accent-blue-dark);
  font-weight: 600;
}

.page-about .update-panel {
  padding-block: 48px;
}

.page-about .update-timeline {
  display: grid;
  gap: 22px;
  margin-left: 10px;
  padding-left: 26px;
  border-left: 3px solid var(--ink);
}

.page-about .update-node {
  position: relative;
}

.page-about .update-node::before {
  content: "";
  position: absolute;
  top: 10px;
  left: -35px;
  width: 14px;
  height: 14px;
  border: 2px solid var(--ink);
  background: var(--accent);
}

.page-about .update-node__index {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  color: var(--accent);
}

.page-about .update-node__body {
  padding: 18px 20px;
  border: 2px solid var(--ink);
  background: var(--card-white);
  box-shadow: var(--about-shadow-soft);
}

.page-about .update-node__body h3 {
  margin: 0 0 6px;
  font-size: 18px;
  font-family: var(--font-heading);
  font-weight: 800;
}

.page-about .update-node__body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.65;
  color: var(--gray);
}

.page-about .update-more {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 32px;
}

.page-about .access-panel {
  padding-block: 48px;
  color: #fff;
}

.page-about .access-panel .block-head {
  border-bottom-color: rgba(255, 255, 255, 0.45);
}

.page-about .access-panel .section-title {
  color: #fff;
}

.page-about .access-panel .block-head__desc {
  color: rgba(255, 255, 255, 0.72);
}

.page-about .section-no--light {
  background: transparent;
  border-color: var(--accent);
  color: var(--accent);
}

.page-about .access-figure {
  margin: 0 0 32px;
  padding: 10px;
  border: 2px solid var(--ink);
  background: rgba(255, 255, 255, 0.08);
}

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

.page-about .access-grid {
  display: grid;
  gap: 20px;
}

.page-about .access-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 24px;
  border: 2px solid var(--ink);
  background: var(--card-white);
  box-shadow: 6px 6px 0 rgba(0, 0, 0, 0.5);
  color: var(--ink);
}

.page-about .access-card__icon {
  font-size: 36px;
  line-height: 1;
  color: var(--accent);
  font-family: var(--font-mono);
}

.page-about .access-card--pc .access-card__icon {
  color: var(--accent-blue);
}

.page-about .access-card--ios .access-card__icon {
  color: var(--tag-teal);
}

.page-about .access-card--android .access-card__icon {
  color: var(--tag-coral);
}

.page-about .access-card h3 {
  margin: 0;
  font-family: var(--font-heading);
  font-size: 21px;
  font-weight: 800;
}

.page-about .access-card p {
  flex: 1;
  margin: 0;
  font-size: 14px;
  line-height: 1.65;
  color: var(--gray);
}

.page-about .access-card__tag {
  align-self: flex-start;
  padding: 4px 8px;
  border: 2px solid var(--ink);
  background: var(--tag-yellow);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
}

.page-about .access-card--ios .access-card__tag {
  background: var(--tag-teal);
  color: #fff;
}

.page-about .access-card--android .access-card__tag {
  background: var(--tag-coral);
  color: #fff;
}

@media (hover: hover) {
  .page-about .stat-card__extra {
    display: none;
  }

  .page-about .stat-card:hover .stat-card__extra {
    display: block;
  }

  .page-about .stat-card:hover {
    transform: translateY(-4px);
    box-shadow: 8px 8px 0 rgba(26, 26, 26, 0.35);
  }

  .page-about .access-card:hover {
    transform: translateY(-3px);
  }
}

@media (hover: none) {
  .page-about .stat-card__extra {
    position: static;
    display: block;
    margin-top: 8px;
    padding: 0;
    background: transparent;
    color: inherit;
    border: none;
    box-shadow: none;
    font-size: 13px;
    opacity: 0.85;
  }
}

@media (min-width: 480px) {
  .page-about .stat-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
  }

  .page-about .taxonomy-cats {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 768px) {
  .page-about .scope-split {
    grid-template-columns: 1fr 1fr;
    gap: 28px;
  }

  .page-about .taxonomy-cats {
    grid-template-columns: repeat(3, 1fr);
  }

  .page-about .update-timeline {
    gap: 26px;
  }

  .page-about .access-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .page-about .access-figure {
    margin-inline: auto;
    max-width: 640px;
  }
}

@media (min-width: 960px) {
  .page-about .stat-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .page-about .taxonomy-cats {
    grid-template-columns: repeat(4, 1fr);
  }
}

@media (min-width: 1200px) {
  .page-about .stat-grid {
    grid-template-columns: repeat(6, 1fr);
  }

  .page-about .taxonomy-layout {
    grid-template-columns: 1.4fr 0.6fr;
    align-items: start;
  }

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