.page-about {
  position: relative;
  min-height: 100vh;
  background-color: var(--paper);
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 32px 32px;
  color: var(--ink);
  font-family: var(--font-body);
  line-height: 1.7;
  overflow-x: hidden;
}

.page-about *,
.page-about *::before,
.page-about *::after {
  box-sizing: border-box;
}

.page-about a {
  color: var(--night);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  transition: color 0.2s ease, background-color 0.2s ease;
}

.page-about a:hover {
  color: var(--orange);
}

.page-about .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  max-width: var(--container);
  margin: 0 auto;
  padding: 24px var(--space-md) 0;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.page-about .breadcrumb-sep {
  color: var(--warm-line);
}

.page-about .breadcrumb [aria-current="page"] {
  color: var(--ink);
  font-weight: 700;
}

/* ---------- Hero Boxed Window ---------- */
.page-about .about-hero {
  max-width: var(--container);
  margin: 24px auto 64px;
  padding: 0 var(--space-md);
}

.page-about .hero-window {
  border: 2px solid var(--ink);
  background-color: var(--paper);
  box-shadow: var(--shadow-card);
}

.page-about .window-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  background-color: var(--ink);
  border-bottom: 2px solid var(--ink);
}

.page-about .window-dot {
  width: 12px;
  height: 12px;
  border: 1px solid rgba(255,255,255,0.5);
}

.page-about .dot-red { background-color: var(--orange); }
.page-about .dot-yellow { background-color: var(--cream); }
.page-about .dot-green { background-color: var(--sea); }

.page-about .window-title {
  margin-left: auto;
  color: rgba(255,255,255,0.8);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.05em;
}

.page-about .hero-content {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  padding: 24px;
}

.page-about .hero-text {
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.page-about .coordinate-label {
  display: inline-block;
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--orange);
  text-transform: uppercase;
}

.page-about .hero-text h1 {
  margin: 0 0 16px;
  font-family: var(--font-heading);
  font-size: 2rem;
  font-weight: 900;
  line-height: 1.25;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.page-about .hero-lead {
  margin: 0 0 24px;
  font-size: 1rem;
}

.page-about .hero-toc {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.page-about .toc-link {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--ink);
  text-decoration: none;
  padding: 4px 8px;
  border: 1px solid var(--warm-line);
  transition: border-color 0.2s ease, background-color 0.2s ease, color 0.2s ease;
}

.page-about .toc-link:hover {
  border-color: var(--orange);
  background-color: var(--orange);
  color: var(--paper);
}

.page-about .hero-visual {
  position: relative;
}

.page-about .hero-img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  border: 1px solid var(--warm-line);
}

.page-about .hero-caption {
  margin: 12px 0 0;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--night);
}

/* ---------- Shared Section Head ---------- */
.page-about .about-section {
  max-width: var(--container);
  margin: 0 auto;
  padding: 64px var(--space-md);
  scroll-margin-top: 24px;
}

.page-about .section-head {
  margin-bottom: 24px;
}

.page-about .section-mark {
  display: inline-block;
  width: 12px;
  height: 12px;
  margin-right: 8px;
  background-color: var(--orange);
  border: 1px solid var(--ink);
  transform: translateY(-2px);
}

.page-about .section-head h2 {
  display: inline;
  margin: 0;
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 900;
  line-height: 1.3;
  color: var(--ink);
}

.page-about .section-desc {
  margin: 12px 0 0;
  font-size: 1rem;
  max-width: 680px;
}

/* ---------- Origin Section ---------- */
.page-about .origin-section {
  background-color: rgba(245, 239, 224, 0.7);
  border-top: 1px solid var(--warm-line);
  border-bottom: 1px solid var(--warm-line);
}

.page-about .origin-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  align-items: center;
}

.page-about .origin-text p {
  margin: 0 0 16px;
}

.page-about .origin-visual {
  order: -1;
}

.page-about .image-shell {
  overflow: hidden;
  border: 1px solid var(--warm-line);
  background-color: var(--glass);
}

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

/* ---------- Milestones Section ---------- */
.page-about .milestones-section {
  position: relative;
}

.page-about .legend-note {
  display: flex;
  gap: 24px;
  margin: 16px 0 24px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
}

.page-about .legend-item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.page-about .legend-dot {
  width: 12px;
  height: 12px;
  border: 2px solid var(--ink);
  border-radius: 50%;
  background-color: var(--paper);
}

.page-about .legend-square {
  width: 12px;
  height: 12px;
  border: 2px solid var(--ink);
  background-color: var(--orange);
}

.page-about .milestone-svg {
  margin-bottom: 32px;
  overflow-x: auto;
  border: 1px solid var(--warm-line);
  background-color: rgba(255, 255, 255, 0.4);
}

.page-about .milestone-svg svg {
  display: block;
  width: 100%;
  min-width: 800px;
  height: auto;
}

.page-about .milestone-svg .node circle {
  transition: fill 0.2s ease, transform 0.2s ease;
}

.page-about .milestone-svg .node:hover circle {
  fill: var(--orange);
}

.page-about .milestone-svg .node-current:hover rect {
  fill: var(--night);
}

.page-about .milestone-cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.page-about .milestone-card {
  position: relative;
  padding: 24px 24px 16px;
  border: 1px solid var(--warm-line);
  background-color: var(--glass);
  box-shadow: 0 2px 0 rgba(14, 27, 42, 0.05);
  transition: border-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
}

.page-about .milestone-card:hover {
  border-color: var(--orange);
  transform: translateY(-2px);
  box-shadow: var(--shadow-card);
}

.page-about .milestone-card h3 {
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 8px 0 8px;
  font-family: var(--font-mono);
  font-size: 1.25rem;
  font-weight: 700;
}

.page-about .status-chip {
  display: inline-block;
  padding: 2px 8px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  border: 1px solid currentColor;
  vertical-align: middle;
}

.page-about .status-chip[data-status="archived"] { color: var(--sea); }
.page-about .status-chip[data-status="online"] { color: var(--night); }
.page-about .status-chip[data-status="new"] { color: var(--orange); }

.page-about .milestone-footer {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 24px;
  margin-top: 32px;
}

.page-about .text-link {
  font-weight: 700;
  text-decoration: none;
  border-bottom: 1px solid currentColor;
  transition: color 0.2s ease;
}

.page-about .text-link:hover {
  color: var(--orange);
}

/* ---------- Data Section ---------- */
.page-about .data-section {
  background-color: var(--ink);
  color: var(--paper);
  border-top: 4px solid var(--orange);
  border-bottom: 4px solid var(--orange);
  max-width: none;
  padding-left: 0;
  padding-right: 0;
}

.page-about .data-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 64px var(--space-md);
}

.page-about .data-section .section-head h2 {
  color: var(--paper);
}

.page-about .data-section .section-desc {
  color: rgba(245, 239, 224, 0.8);
}

.page-about .data-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin-top: 32px;
}

.page-about .data-card {
  padding: 24px;
  background-color: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(245, 239, 224, 0.3);
  transition: border-color 0.2s ease, background-color 0.2s ease, transform 0.2s ease;
}

.page-about .data-card:hover {
  border-color: var(--orange);
  background-color: rgba(255, 255, 255, 0.12);
  transform: translateY(-2px);
}

.page-about .stat-num {
  display: block;
  font-family: var(--font-heading);
  font-size: 3.5rem;
  font-weight: 900;
  line-height: 1.1;
  color: var(--orange);
}

.page-about .stat-label {
  display: inline-block;
  margin: 8px 0 8px;
  padding-bottom: 4px;
  border-bottom: 2px solid var(--orange);
  font-size: 0.9rem;
  font-weight: 700;
}

.page-about .data-card p {
  margin: 8px 0 0;
  font-size: 0.9rem;
  color: rgba(245, 239, 224, 0.7);
}

/* ---------- Philosophy Section ---------- */
.page-about .philosophy-section {
  position: relative;
}

.page-about .container-narrow {
  max-width: var(--container-narrow);
  margin: 0 auto;
}

.page-about .philosophy-quote {
  margin: 32px 0 24px;
  padding-left: 16px;
  border-left: 4px solid var(--orange);
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 900;
  line-height: 1.4;
  color: var(--ink);
}

.page-about .philosophy-section p {
  margin: 0 0 16px;
}

.page-about .philosophy-features {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 32px;
}

.page-about .feature-item {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 16px;
  border: 1px solid var(--warm-line);
  background-color: rgba(255, 255, 255, 0.6);
  transition: border-color 0.2s ease, background-color 0.2s ease;
}

.page-about .feature-item:hover {
  border-color: var(--orange);
  background-color: var(--glass);
}

.page-about .feature-index {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--orange);
}

.page-about .feature-item span:last-child {
  font-weight: 700;
}

/* ---------- Ecosystem Section ---------- */
.page-about .ecosystem-section {
  background-color: rgba(245, 239, 224, 0.7);
  border-top: 1px solid var(--warm-line);
  border-bottom: 1px solid var(--warm-line);
}

.page-about .eco-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  align-items: center;
}

.page-about .eco-visual {
  order: -1;
}

.page-about .image-shell-4x3 img {
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

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

.page-about .compat-list li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 0;
  border-bottom: 1px solid var(--warm-line);
}

.page-about .compat-name {
  font-weight: 700;
}

/* ---------- Buttons ---------- */
.page-about .btn {
  display: inline-block;
  padding: 12px 24px;
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 700;
  line-height: 1.2;
  text-decoration: none;
  border: 2px solid var(--ink);
  box-shadow: 3px 3px 0 rgba(14, 27, 42, 0.15);
  transition: background-color 0.2s ease, color 0.2s ease, box-shadow 0.2s ease, transform 0.2s ease;
}

.page-about .btn:hover {
  transform: translate(1px, 1px);
  box-shadow: 1px 1px 0 rgba(14, 27, 42, 0.15);
}

.page-about .btn-primary {
  background-color: var(--orange);
  color: var(--paper);
}

.page-about .btn-primary:hover {
  background-color: var(--night);
  color: var(--paper);
  border-color: var(--night);
}

.page-about .btn-ghost {
  background-color: var(--paper);
  color: var(--ink);
}

.page-about .btn-ghost:hover {
  background-color: var(--orange);
  color: var(--paper);
  border-color: var(--orange);
}

.page-about .btn-dark {
  background-color: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

.page-about .btn-dark:hover {
  background-color: var(--night);
  color: var(--paper);
}

/* ---------- Footer Note ---------- */
.page-about .about-footer-note {
  max-width: var(--container-narrow);
  margin: 0 auto;
  padding: 48px var(--space-md) 80px;
  text-align: center;
  border-top: 1px dashed var(--warm-line);
}

.page-about .about-footer-note p {
  margin: 0 0 8px;
  font-size: 0.9rem;
}

.page-about .about-footer-note a {
  font-weight: 700;
}

/* ---------- Desktop Media Query ---------- */
@media (min-width: 768px) {
  .page-about .hero-content {
    grid-template-columns: 1fr 1fr;
    padding: 40px;
  }

  .page-about .hero-text h1 {
    font-size: 2.75rem;
  }

  .page-about .hero-lead {
    font-size: 1.1rem;
  }

  .page-about .origin-grid {
    grid-template-columns: 7fr 5fr;
  }

  .page-about .origin-visual {
    order: 1;
  }

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

  .page-about .milestone-svg {
    overflow-x: visible;
  }

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

  .page-about .eco-grid {
    grid-template-columns: 5fr 7fr;
  }

  .page-about .eco-visual {
    order: 1;
  }

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

@media (min-width: 1024px) {
  .page-about .about-hero {
    padding: 0 var(--gutter);
  }

  .page-about .hero-content {
    padding: 48px;
  }

  .page-about .hero-text h1 {
    font-size: 3.25rem;
  }

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