.page-about {
  --about-chip: #F5F5F5;
  --about-ink: #212121;
  --about-muted: #666666;
  --about-line: #BDBDBD;
  --about-dark-panel: #3A3A3A;
  --about-tag-hot: #FF6D00;
  --about-tag-warm: #E64A19;
  --about-tag-cool: #3F51B5;
}

.page-about .about-breadcrumb-wrap {
  padding-top: 1rem;
  padding-bottom: 0.25rem;
}

.page-about .about-hero {
  padding: 1.5rem 0 3rem;
}

.page-about .about-hero-grid {
  display: grid;
  gap: 1.5rem;
  align-items: stretch;
}

.page-about .about-hero-copy {
  border: 1px solid var(--glass-border);
  padding: 1.5rem;
}

.page-about .about-hero-copy h1 {
  font-family: var(--font-display);
  font-size: clamp(1.55rem, 4vw, 2.5rem);
  line-height: 1.18;
  margin: 0.6rem 0 1rem;
  color: var(--ink-invert);
}

.page-about .about-lead {
  font-size: 1.05rem;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.88);
  margin-bottom: 0.9rem;
}

.page-about .about-lead-sub {
  font-size: 0.93rem;
  line-height: 1.65;
  color: rgba(255, 255, 255, 0.62);
  margin: 0;
}

.page-about .about-stat-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
}

.page-about .about-stat-card {
  background: var(--about-chip);
  border-radius: var(--radius);
  padding: 1rem 0.9rem;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  min-height: 120px;
  justify-content: center;
}

.page-about .about-stat-card--total {
  grid-column: 1 / -1;
  background: var(--accent);
}

.page-about .stat-num {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 900;
  line-height: 1;
  color: var(--about-ink);
}

.page-about .about-stat-card--total .stat-num {
  color: #FFFFFF;
  font-size: 2.6rem;
}

.page-about .stat-label {
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--about-muted);
  text-transform: uppercase;
}

.page-about .stat-note {
  font-size: 0.75rem;
  color: var(--about-muted);
  font-family: var(--font-mono);
}

.page-about .about-stat-card--total .stat-label,
.page-about .about-stat-card--total .stat-note {
  color: rgba(255, 255, 255, 0.9);
}

.page-about .stat-dots {
  display: flex;
  gap: 0.3rem;
  margin-top: 0.45rem;
}

.page-about .stat-dots span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: block;
}

.page-about .stat-dots .z1 { background: var(--zone-1); }
.page-about .stat-dots .z2 { background: var(--zone-2); }
.page-about .stat-dots .z3 { background: var(--zone-3); }
.page-about .stat-dots .z4 { background: var(--zone-4); }
.page-about .stat-dots .z5 { background: var(--zone-5); }
.page-about .stat-dots .z6 { background: var(--zone-6); }

.page-about .about-hierarchy {
  padding: 3rem 0;
  background: rgba(255, 255, 255, 0.03);
  border-top: 1px solid var(--line-dark);
  border-bottom: 1px solid var(--line-dark);
}

.page-about .section-intro {
  font-size: 0.95rem;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.7);
  max-width: 880px;
}

.page-about .hierarchy-root {
  margin-top: 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.page-about .root-node {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  background: var(--surface-bright);
  border: 2px solid var(--accent);
  border-radius: calc(var(--radius) * 2);
  padding: 0.7rem 1.2rem;
  font-family: var(--font-display);
  font-size: 1.15rem;
  color: var(--about-ink);
  box-shadow: var(--shadow);
}

.page-about .root-ring {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px rgba(255, 109, 0, 0.22);
  flex-shrink: 0;
}

.page-about .root-total {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  background: var(--accent);
  color: #FFFFFF;
  padding: 0.22rem 0.5rem;
  border-radius: 2px;
}

.page-about .hierarchy-root::after {
  content: "";
  width: 2px;
  height: 1.1rem;
  background: var(--accent);
  opacity: 0.6;
  display: block;
}

.page-about .hierarchy-map {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
  width: 100%;
}

.page-about .hier-branch {
  background: var(--about-chip);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
}

.page-about .branch-head {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.8rem 1rem;
  color: #FFFFFF;
}

.page-about .hier-branch--z1 .branch-head { background: var(--zone-1); }
.page-about .hier-branch--z2 .branch-head { background: var(--zone-2); }
.page-about .hier-branch--z3 .branch-head { background: var(--zone-3); }
.page-about .hier-branch--z4 .branch-head { background: var(--zone-4); }
.page-about .hier-branch--z5 .branch-head { background: var(--zone-5); }
.page-about .hier-branch--z6 .branch-head { background: var(--zone-6); }

.page-about .hier-branch--z2 .branch-head,
.page-about .hier-branch--z5 .branch-head {
  color: #212121;
}

.page-about .branch-code {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  opacity: 0.85;
  border: 1px solid rgba(255, 255, 255, 0.4);
  padding: 0.1rem 0.4rem;
  border-radius: 2px;
}

.page-about .hier-branch--z2 .branch-code,
.page-about .hier-branch--z5 .branch-code {
  border-color: rgba(33, 33, 33, 0.35);
}

.page-about .branch-title {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.05rem;
  flex: 1;
}

.page-about .branch-count {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  background: rgba(255, 255, 255, 0.18);
  padding: 0.2rem 0.45rem;
  border-radius: 2px;
  white-space: nowrap;
}

.page-about .hier-branch--z2 .branch-count,
.page-about .hier-branch--z5 .branch-count {
  background: rgba(33, 33, 33, 0.12);
}

.page-about .branch-subs {
  list-style: none;
  margin: 0;
  padding: 0.8rem 1rem 0.4rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.45rem 0.6rem;
}

.page-about .branch-subs li {
  font-size: 0.88rem;
  color: var(--about-ink);
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-weight: 600;
}

.page-about .sub-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  flex-shrink: 0;
}

.page-about .branch-tags {
  padding: 0 1rem 0.8rem;
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
  margin-top: auto;
}

.page-about .branch-tags .tag {
  font-size: 0.7rem;
  background: #FFFFFF;
  border: 1px solid var(--about-line);
  color: var(--about-muted);
  padding: 0.18rem 0.45rem;
}

.page-about .hierarchy-tagrow {
  margin-top: 1.5rem;
  background: var(--about-dark-panel);
  padding: 1rem 1.1rem;
  border-radius: var(--radius);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  border: 1px solid var(--line-dark);
}

.page-about .tagrow-label {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 0.85rem;
  color: #FFFFFF;
  letter-spacing: 0.06em;
  margin-right: 0.3rem;
}

.page-about .hierarchy-tagrow .tag {
  font-size: 0.78rem;
  padding: 0.3rem 0.6rem;
  border-radius: 2px;
  border: 1px solid transparent;
  color: #FFFFFF;
  text-decoration: none;
  font-family: var(--font-body);
}

.page-about .hierarchy-tagrow .tag--hot {
  background: var(--about-tag-hot);
}

.page-about .hierarchy-tagrow .tag--warm {
  background: var(--about-tag-warm);
}

.page-about .hierarchy-tagrow .tag--cool {
  background: var(--about-tag-cool);
}

.page-about .about-figure {
  margin: 1.5rem 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--line-dark);
  border-radius: var(--radius);
  background: #1A1A1A;
}

.page-about .about-figure figcaption {
  font-size: 0.75rem;
  color: var(--about-muted);
  padding-top: 0.45rem;
  font-family: var(--font-mono);
}

.page-about .about-updates {
  padding: 3rem 0;
  background: rgba(0, 0, 0, 0.16);
}

.page-about .update-layout {
  display: grid;
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.page-about .timeline {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.page-about .tl-item {
  display: grid;
  grid-template-columns: 4.2em 1fr;
  gap: 0.8rem;
}

.page-about .tl-mark {
  padding-top: 0.55rem;
}

.page-about .tl-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.3rem 0.5rem;
  border-radius: 2px;
  background: var(--about-chip);
  color: var(--about-ink);
  border: 1px solid var(--about-line);
}

.page-about .tl-card {
  background: var(--about-chip);
  border-left: 4px solid var(--about-line);
  border-radius: var(--radius);
  padding: 1rem 1.1rem;
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  box-shadow: var(--shadow);
}

.page-about .tl-current .tl-card {
  border-left-color: var(--accent);
  background: #FFF8F0;
}

.page-about .tl-batch {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
  font-weight: 700;
  letter-spacing: 0.05em;
}

.page-about .tl-card h3 {
  margin: 0.15rem 0 0;
  font-size: 1.05rem;
  color: var(--about-ink);
}

.page-about .tl-card p {
  margin: 0.2rem 0 0;
  font-size: 0.88rem;
  line-height: 1.6;
  color: var(--about-muted);
}

.page-about .tl-status {
  margin-top: 0.55rem;
}

.page-about .timeline-figure {
  margin: 0;
}

.page-about .timeline-figure img {
  width: 100%;
  height: auto;
  border-radius: var(--radius);
  border: 1px solid var(--line-dark);
  background: #1A1A1A;
}

.page-about .about-paths {
  padding: 3rem 0;
}

.page-about .path-grid {
  display: grid;
  gap: 1rem;
  margin-top: 1.5rem;
}

.page-about .path-card {
  background: var(--about-chip);
  border-radius: var(--radius);
  padding: 1.3rem 1.2rem 1.2rem;
  text-decoration: none;
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  display: block;
}

.page-about .path-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.35);
}

.page-about .path-num {
  font-family: var(--font-mono);
  font-size: 2.2rem;
  font-weight: 900;
  color: var(--accent);
  opacity: 0.22;
  position: absolute;
  top: 0.6rem;
  right: 0.9rem;
  line-height: 1;
}

.page-about .path-card h3 {
  margin: 0 0 0.5rem;
  font-size: 1.05rem;
  color: var(--about-ink);
  font-family: var(--font-display);
  padding-right: 2.4rem;
}

.page-about .path-card p {
  margin: 0 0 0.8rem;
  font-size: 0.85rem;
  line-height: 1.65;
  color: var(--about-muted);
}

.page-about .path-tags {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
}

.page-about .path-tags .tag {
  font-size: 0.7rem;
  background: #FFFFFF;
  border: 1px solid var(--about-line);
  color: var(--about-muted);
  padding: 0.2rem 0.5rem;
}

.page-about .about-version {
  padding: 3rem 0;
  background: rgba(255, 255, 255, 0.03);
  border-top: 1px solid var(--line-dark);
}

.page-about .version-layout {
  display: grid;
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.page-about .version-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.page-about .version-row {
  display: grid;
  grid-template-columns: auto auto 1fr;
  align-items: center;
  gap: 0.75rem;
  background: var(--about-chip);
  border-radius: var(--radius);
  padding: 0.9rem 1rem;
  box-shadow: var(--shadow);
}

.page-about .version-flag {
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--info);
  border: 1px solid currentColor;
  padding: 0.2rem 0.45rem;
  border-radius: 2px;
  letter-spacing: 0.06em;
  white-space: nowrap;
}

.page-about .version-name {
  font-family: var(--font-mono);
  font-weight: 900;
  font-size: 1.15rem;
  color: var(--about-ink);
  white-space: nowrap;
}

.page-about .version-detail {
  font-size: 0.83rem;
  color: var(--about-muted);
  line-height: 1.5;
}

.page-about .device-panel {
  background: var(--about-chip);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
}

.page-about .device-figure {
  margin: 0;
  border-bottom: 1px solid var(--about-line);
}

.page-about .device-figure img {
  display: block;
  width: 100%;
  height: auto;
  background: #1A1A1A;
}

.page-about .device-rows {
  padding: 0.5rem 1rem 1rem;
}

.page-about .device-row {
  display: grid;
  grid-template-columns: 2.4em 1fr;
  gap: 0.2rem 0.7rem;
  padding: 0.55rem 0;
  border-bottom: 1px dashed var(--about-line);
}

.page-about .device-row:last-child {
  border-bottom: none;
}

.page-about .device-icon {
  grid-row: span 2;
  width: 2.4em;
  min-height: 1.8rem;
  background: #E0E0E0;
  border-radius: 3px;
  position: relative;
  display: block;
}

.page-about .dev-desk::before {
  content: "";
  position: absolute;
  top: 0.25rem;
  left: 0.3rem;
  right: 0.3rem;
  height: 0.6rem;
  background: #BDBDBD;
  border-radius: 1px;
}

.page-about .dev-tab::before {
  content: "";
  position: absolute;
  top: 0.2rem;
  left: 0.6rem;
  right: 0.6rem;
  height: 0.9rem;
  background: #BDBDBD;
  border-radius: 1px;
}

.page-about .dev-phone::before {
  content: "";
  position: absolute;
  top: 0.25rem;
  left: 0.9rem;
  right: 0.9rem;
  height: 1.4rem;
  background: #BDBDBD;
  border-radius: 1px;
}

.page-about .device-name {
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--about-ink);
}

.page-about .device-desc {
  font-size: 0.8rem;
  color: var(--about-muted);
  line-height: 1.5;
}

@media (min-width: 640px) {
  .page-about .about-stat-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .page-about .about-stat-card--total {
    grid-column: 1 / -1;
  }

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

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

  .page-about .tl-item {
    grid-template-columns: 5em 1fr;
  }

  .page-about .version-row {
    grid-template-columns: auto auto 1fr;
  }
}

@media (min-width: 960px) {
  .page-about .about-hero-grid {
    grid-template-columns: 1.1fr 1fr;
  }

  .page-about .about-hero-copy {
    padding: 2rem;
  }

  .page-about .hierarchy-map {
    grid-template-columns: repeat(3, 1fr);
    gap: 1.2rem;
  }

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

  .page-about .update-layout,
  .page-about .version-layout {
    grid-template-columns: 1.2fr 0.9fr;
  }
}