.page-about {
  --about-grid-line: rgba(255, 255, 255, 0.045);
  --about-blue-ink: #04181f;
  --about-green-ink: #052b08;
  --about-hero-line: linear-gradient(90deg, var(--zone-purple), var(--zone-green), var(--zone-orange), var(--zone-blue));
}

.page-about .crumb-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--ink-dim);
  padding-top: var(--space-2);
}
.page-about .crumb-row a {
  color: var(--accent-key);
  text-decoration: none;
}
.page-about .crumb-row a:hover {
  text-decoration: underline;
}

.page-about .about-hero {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  border-bottom: 1px solid var(--line);
  padding: var(--space-3) 0 var(--space-4);
}
@media (min-width: 768px) {
  .page-about .about-hero {
    flex-direction: row;
    align-items: flex-end;
    justify-content: space-between;
  }
}

.page-about .about-hero-copy {
  max-width: 820px;
}
.page-about .about-hero-copy .sec-label {
  color: var(--zone-blue);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
}
.page-about .about-hero-copy h1 {
  font-family: var(--font-display);
  font-size: clamp(28px, 5vw, 46px);
  line-height: 1.06;
  margin: var(--space-1) 0 var(--space-2);
  color: var(--ink);
}
.page-about .about-hero-desc {
  color: var(--ink-dim);
  font-size: 15px;
  line-height: 1.7;
  max-width: 68ch;
  margin: 0;
}
.page-about .about-hero-desc strong {
  color: var(--accent-key);
  font-family: var(--font-mono);
  font-weight: 700;
}
.page-about .about-hero-side {
  display: flex;
  align-items: center;
}
.page-about .about-hero-meta {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-wrap: wrap;
  background: var(--bg-panel);
  border: 1px solid var(--line);
  padding: var(--space-2);
}
.page-about .about-hero-meta .id-marker {
  background: var(--accent-key);
  color: var(--ink-on-color);
  font-weight: 700;
  padding: 4px 8px;
}

.page-about .section-head {
  display: flex;
  align-items: flex-start;
  gap: var(--space-2);
  margin-bottom: var(--space-3);
  position: relative;
}
.page-about .section-head::after {
  content: "";
  position: absolute;
  bottom: -6px;
  left: 0;
  width: 140px;
  height: 3px;
  background: var(--about-hero-line);
  opacity: 0.8;
}
.page-about .section-head .id-marker {
  flex-shrink: 0;
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--accent-key);
  background: var(--bg-panel);
  border: 1px solid var(--line-bright);
  padding: 6px 10px;
  letter-spacing: 0.05em;
}
.page-about .section-head-text h2 {
  font-family: var(--font-display);
  font-size: clamp(22px, 3vw, 32px);
  margin: 0 0 4px;
  line-height: 1.12;
}
.page-about .sec-note {
  color: var(--ink-dim);
  font-size: 14px;
  margin: 0;
}

.page-about .about-scale {
  background-image:
    linear-gradient(var(--about-grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--about-grid-line) 1px, transparent 1px);
  background-size: 28px 28px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-stat-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-2);
  margin-bottom: var(--space-4);
}
@media (min-width: 900px) {
  .page-about .about-stat-grid {
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-3);
  }
}

.page-about .about-stat {
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-top: 4px solid var(--line-bright);
  padding: var(--space-3) var(--space-2);
  display: flex;
  flex-direction: column;
  gap: 6px;
  position: relative;
  overflow: hidden;
}
.page-about .about-stat::after {
  content: "";
  position: absolute;
  inset: auto 0 0;
  height: 20px;
  background-image: linear-gradient(135deg, transparent 12px, var(--about-grid-line) 12px, var(--about-grid-line) 13px, transparent 13px);
  background-size: 16px 16px;
  opacity: 0.6;
}
.page-about .about-stat-purple {
  border-top-color: var(--zone-purple);
}
.page-about .about-stat-green {
  border-top-color: var(--zone-green);
}
.page-about .about-stat-orange {
  border-top-color: var(--zone-orange);
}
.page-about .about-stat-blue {
  border-top-color: var(--zone-blue);
}
.page-about .about-stat-label {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--ink-dim);
  letter-spacing: 0.08em;
}
.page-about .about-stat-value {
  font-family: var(--font-display);
  font-size: clamp(36px, 5vw, 52px);
  line-height: 1;
  color: var(--accent-key);
}
.page-about .about-stat-unit {
  font-size: 12px;
  color: var(--ink-dim);
}

.page-about .about-tree-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-3);
}
@media (min-width: 900px) {
  .page-about .about-tree-layout {
    grid-template-columns: 400px 1fr;
    align-items: start;
  }
}
.page-about .about-tree-figure {
  margin: 0;
  border: 1px solid var(--line-bright);
  background: var(--bg-panel);
  padding: var(--space-2);
}
.page-about .about-tree-figure img {
  width: 100%;
  height: auto;
  display: block;
  object-fit: cover;
}

.page-about .about-tree {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.page-about .tree-category {
  background: var(--bg-panel);
  border: 1px solid var(--line);
}
.page-about .tree-root {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2);
  border-bottom: 1px solid var(--line);
  font-size: 16px;
  cursor: pointer;
}
.page-about .tree-root-dot {
  width: 10px;
  height: 10px;
  flex-shrink: 0;
  box-shadow: 0 0 8px currentColor;
}
.page-about .tree-dot-purple {
  background: var(--zone-purple);
  color: var(--zone-purple);
}
.page-about .tree-dot-green {
  background: var(--zone-green);
  color: var(--zone-green);
}
.page-about .tree-dot-orange {
  background: var(--zone-orange);
  color: var(--zone-orange);
}
.page-about .tree-dot-blue {
  background: var(--zone-blue);
  color: var(--zone-blue);
}
.page-about .tree-root-name {
  font-weight: 700;
  color: var(--ink);
  flex-shrink: 0;
}
.page-about .tree-root-count {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--ink-dim);
  border: 1px solid var(--line-bright);
  padding: 2px 6px;
  background: var(--bg-lift);
}
.page-about .tree-root::after {
  content: "−";
  font-family: var(--font-mono);
  color: var(--accent-key);
  width: 20px;
  text-align: center;
  font-weight: 700;
}
.page-about .tree-category:not([data-open]) .tree-root::after {
  content: "+";
}
.page-about .tree-category:not([data-open]) .tree-sublist {
  display: none;
}
.page-about .tree-sublist {
  display: flex;
  flex-direction: column;
  padding: var(--space-2);
  gap: 4px;
}
.page-about .tree-sub {
  display: block;
  color: var(--ink-dim);
  text-decoration: none;
  font-size: 14px;
  padding: 6px 8px 6px 28px;
  border-left: 2px solid var(--line);
  transition: color var(--transition), border-color var(--transition), background var(--transition);
}
.page-about .tree-sub:hover {
  color: var(--ink);
  border-left-color: var(--accent-key);
  background: var(--bg-lift);
}

.page-about .about-batch {
  background-image:
    linear-gradient(rgba(0, 0, 0, 0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 0, 0, 0.06) 1px, transparent 1px);
  background-size: 24px 24px;
}
.page-about .about-batch .section-head .id-marker {
  background: var(--zone-purple);
  color: var(--ink);
  border-color: transparent;
}
.page-about .about-batch .section-head-text h2 {
  color: var(--ink);
}
.page-about .about-batch .sec-note {
  color: rgba(224, 224, 224, 0.72);
}

.page-about .about-batch-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-3);
}
@media (min-width: 900px) {
  .page-about .about-batch-layout {
    grid-template-columns: 1.4fr 0.8fr;
    align-items: start;
  }
}

.page-about .batch-timeline {
  display: flex;
  flex-direction: column;
  position: relative;
  padding-left: 0;
}
.page-about .batch-timeline::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 20px;
  width: 2px;
  background: var(--line-bright);
  opacity: 0.45;
}
@media (min-width: 700px) {
  .page-about .batch-timeline::before {
    left: 24px;
  }
}
.page-about .batch-item {
  display: flex;
  gap: var(--space-2);
  position: relative;
  margin-bottom: var(--space-2);
}
.page-about .batch-idx {
  flex-shrink: 0;
  width: 42px;
  height: 42px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-panel);
  border: 2px solid var(--accent-key);
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 16px;
  color: var(--accent-key);
  z-index: 1;
}
@media (min-width: 700px) {
  .page-about .batch-idx {
    width: 48px;
    height: 48px;
    font-size: 18px;
  }
}
.page-about .batch-card {
  flex: 1;
  background: var(--bg-panel);
  border: 1px solid var(--line-bright);
  padding: var(--space-2) var(--space-3) var(--space-3);
}
.page-about .batch-card-head {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: 6px;
}
.page-about .batch-count {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent-key);
}
.page-about .batch-card h3 {
  font-size: 17px;
  margin: 0 0 4px;
  color: var(--ink);
}
.page-about .batch-card p {
  font-size: 13px;
  color: var(--ink-dim);
  line-height: 1.6;
  margin: 0;
}

.page-about .batch-aside {
  background: var(--bg-panel);
  border: 1px solid var(--line-bright);
  padding: var(--space-3);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  text-align: center;
}
.page-about .batch-aside-icon {
  border: 1px dashed var(--line-bright);
  padding: 8px;
  max-width: 100%;
  height: auto;
}
.page-about .batch-meta-list {
  width: 100%;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}
.page-about .batch-meta-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-2);
  padding: 10px 0;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
}
.page-about .batch-meta-row dt {
  color: var(--ink-dim);
  font-family: var(--font-mono);
  font-size: 12px;
}
.page-about .batch-meta-row dd {
  margin: 0;
  color: var(--accent-key);
  font-weight: 700;
}

.page-about .about-search .section-head .id-marker {
  background: var(--zone-blue);
  color: var(--ink-on-color);
  border-color: transparent;
}
.page-about .about-search .section-head-text h2 {
  color: var(--about-blue-ink);
}
.page-about .about-search .sec-note {
  color: rgba(4, 24, 31, 0.75);
}
.page-about .about-search-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-3);
}
@media (min-width: 768px) {
  .page-about .about-search-layout {
    grid-template-columns: 1fr 1fr;
    align-items: center;
  }
}
.page-about .about-search-figure {
  margin: 0;
  border: 1px solid var(--ink-on-color);
  background: var(--bg-panel);
  box-shadow: 6px 6px 0 rgba(26, 26, 46, 0.25);
}
.page-about .about-search-figure img {
  width: 100%;
  height: auto;
  display: block;
  object-fit: cover;
}
.page-about .about-search-content {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.page-about .search-mode-card {
  display: flex;
  gap: var(--space-2);
  background: var(--bg-panel);
  border: 1px solid var(--line-bright);
  padding: var(--space-2);
  align-items: flex-start;
}
.page-about .search-mode-idx {
  flex-shrink: 0;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-weight: 700;
  background: var(--ink-on-color);
  color: var(--accent-key);
  border: 1px solid var(--accent-key);
}
.page-about .search-mode-card h3 {
  font-size: 16px;
  margin: 0 0 4px;
  color: var(--accent-key);
}
.page-about .search-mode-card p {
  margin: 0;
  font-size: 13px;
  line-height: 1.6;
  color: var(--ink-dim);
}
.page-about .about-tag-cloud {
  background: var(--bg-panel);
  border: 1px solid var(--line-bright);
  padding: var(--space-3);
}
.page-about .about-tag-cloud h3 {
  font-family: var(--font-mono);
  font-size: 16px;
  letter-spacing: 0.05em;
  margin: 0 0 var(--space-2);
  color: var(--ink);
}
.page-about .about-tag-cloud .tag-set {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.page-about .about-tag-cloud .tag-item {
  font-size: 13px;
  border-width: 1px;
}
.page-about .about-tag-cloud .tag-item-primary {
  font-size: 15px;
  font-weight: 700;
  border-width: 2px;
}

.page-about .about-flow .section-head .id-marker {
  background: var(--zone-green);
  color: var(--ink-on-color);
  border-color: transparent;
}
.page-about .about-flow .section-head-text h2 {
  color: var(--about-green-ink);
}
.page-about .about-flow .sec-note {
  color: rgba(5, 43, 8, 0.78);
}
.page-about .about-flow-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-3);
}
@media (min-width: 800px) {
  .page-about .about-flow-grid {
    grid-template-columns: repeat(4, 1fr);
    position: relative;
  }
  .page-about .about-flow-grid::before {
    content: "";
    position: absolute;
    top: 32px;
    left: 8%;
    right: 8%;
    height: 2px;
    background: var(--about-green-ink);
    opacity: 0.3;
    z-index: 0;
  }
  .page-about .about-flow-grid .flow-step {
    position: relative;
    z-index: 1;
  }
}
.page-about .flow-step {
  background: var(--bg-panel);
  border: 1px solid var(--line-bright);
  padding: var(--space-3);
  display: flex;
  flex-direction: column;
  box-shadow: 4px 4px 0 rgba(26, 26, 46, 0.28);
}
.page-about .flow-step-num {
  font-family: var(--font-display);
  font-size: 40px;
  line-height: 1;
  color: var(--accent-key);
  display: block;
  margin-bottom: var(--space-2);
}
.page-about .flow-step h3 {
  margin: 0 0 6px;
  font-size: 16px;
  color: var(--ink);
}
.page-about .flow-step p {
  margin: 0 0 var(--space-2);
  font-size: 13px;
  color: var(--ink-dim);
  line-height: 1.6;
  flex: 1;
}
.page-about .flow-step-link {
  color: var(--accent-key);
  font-family: var(--font-mono);
  font-size: 13px;
  text-decoration: none;
  border-bottom: 1px dashed var(--accent-key);
  align-self: flex-start;
  transition: border-bottom-style var(--transition);
}
.page-about .flow-step-link:hover {
  border-bottom-style: solid;
}
.page-about .about-feedback-cta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
  margin-top: var(--space-3);
  padding: var(--space-2) var(--space-3);
  background: var(--bg-soft);
  border: 1px solid var(--ink-on-color);
}
.page-about .about-feedback-cta p {
  margin: 0;
  color: var(--ink-on-color);
  font-size: 14px;
  flex: 1;
  min-width: 200px;
}
.page-about .about-feedback-link {
  color: var(--ink-on-color);
  font-weight: 700;
  background: var(--accent-key);
  padding: 8px 12px;
  border: 1px solid var(--ink-on-color);
  text-decoration: none;
  font-family: var(--font-mono);
  font-size: 13px;
  transition: background var(--transition), color var(--transition);
}
.page-about .about-feedback-link:hover {
  background: transparent;
  color: var(--accent-key);
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition: none !important;
    animation: none !important;
  }
}