.page-about {
  --about-gold: var(--color-accent-gold);
  --about-bg-start: var(--color-primary-bg);
  --about-bg-mid: #0F2440;
  --about-bg-deep: #142F50;
  --about-bg-light: #F0F2F5;
  --about-text-light: var(--color-primary-text);
  --about-text-muted: var(--color-text-muted);
  --about-text-dark: #1A1A1A;
  --about-card-shadow: 0 2px 16px rgba(0,0,0,0.3);
  --about-transition: var(--transition-base);
  --about-radius: var(--border-radius);
  --about-max-content: 720px;
  display: block;
  width: 100%;
  background: var(--about-bg-start);
  color: var(--about-text-light);
}

/* breadcrumb */
.page-about .breadcrumb {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--spacing-md) var(--spacing-lg) 0;
  font-family: var(--font-caption);
  font-size: var(--fs-caption);
  color: var(--about-text-muted);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--spacing-xs);
}
.page-about .breadcrumb-link {
  color: var(--about-text-muted);
  text-decoration: none;
  transition: color var(--transition-fast);
}
.page-about .breadcrumb-link:hover,
.page-about .breadcrumb-link:focus {
  color: var(--about-gold);
  outline: 2px solid var(--about-gold);
  outline-offset: 2px;
}
.page-about .breadcrumb-sep {
  color: var(--color-divider);
  user-select: none;
}
.page-about .breadcrumb-current {
  color: var(--about-gold);
  font-weight: var(--fw-special);
}

/* framed viewport */
.page-about .framed-viewport--about {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--spacing-xl) var(--spacing-lg);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-xl);
  border-bottom: 1px solid var(--color-divider);
  position: relative;
}
.page-about .framed-viewport--about::before {
  content: '';
  position: absolute;
  inset: 0;
  border: 1px solid var(--about-gold);
  opacity: 0.12;
  pointer-events: none;
  border-radius: 2px;
}
.page-about .motto-block {
  flex: 1 1 320px;
  min-width: 240px;
}
.page-about .motto-text {
  font-family: var(--font-heading);
  font-weight: var(--fw-heading);
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  line-height: 1.15;
  letter-spacing: var(--ls-heading);
  color: var(--about-text-light);
  margin: 0 0 var(--spacing-md);
  max-width: 540px;
}
.page-about .motto-sub {
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  color: var(--about-text-muted);
  max-width: 400px;
  margin: 0;
}
.page-about .motto-figure {
  flex: 0 0 auto;
  margin: 0;
}
.page-about .motto-img {
  display: block;
  width: 100%;
  max-width: 400px;
  height: auto;
  aspect-ratio: 1/1;
  object-fit: contain;
  background: rgba(255,255,255,0.03);
  border-radius: var(--about-radius);
}

/* section base */
.page-about .about-section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
  border-bottom: 1px solid var(--color-divider);
}
.page-about .about-section--principles { background: var(--about-bg-start); }
.page-about .about-section--boundaries { background: var(--about-bg-mid); }
.page-about .about-section--scenarios { background: var(--about-bg-deep); }
.page-about .about-section--faq { background: var(--about-bg-light); color: var(--about-text-dark); }
.page-about .about-section--faq .section-summary-title,
.page-about .about-section--faq .section-toggle,
.page-about .about-section--faq .faq-q { color: var(--about-text-dark); }
.page-about .about-section--faq .section-number { color: var(--about-gold); }
.page-about .about-section--faq .faq-a { color: #2A2A2A; }

/* details / summary */
.page-about .section-details {
  display: block;
  width: 100%;
  padding: var(--spacing-lg) 0;
}
.page-about .section-summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--spacing-md) var(--spacing-sm);
  cursor: pointer;
  list-style: none;
  padding: var(--spacing-sm) 0;
  user-select: none;
  transition: opacity var(--transition-fast);
}
.page-about .section-summary::-webkit-details-marker { display: none; }
.page-about .section-summary:focus-visible {
  outline: 2px solid var(--about-gold);
  outline-offset: 4px;
}
.page-about .section-number {
  font-family: var(--font-heading);
  font-weight: var(--fw-heading);
  font-size: clamp(2.25rem, 5vw, 4rem);
  line-height: 1;
  color: var(--about-gold);
  opacity: 0.6;
  transition: opacity var(--about-transition), transform var(--about-transition);
  min-width: 2.4em;
}
.page-about .section-summary:hover .section-number,
.page-about .section-summary:focus .section-number {
  opacity: 1;
  transform: scale(1.04);
}
.page-about .section-summary-title {
  font-family: var(--font-heading);
  font-weight: var(--fw-heading);
  font-size: clamp(1.25rem, 2.5vw, 1.75rem);
  letter-spacing: var(--ls-heading);
  color: var(--about-text-light);
  flex: 1 1 auto;
}
.page-about .section-toggle {
  font-size: 1.2rem;
  line-height: 1;
  color: var(--about-gold);
  transition: transform var(--about-transition);
  margin-left: auto;
}
.page-about .section-details[open] .section-toggle {
  transform: rotate(180deg);
}

/* section content */
.page-about .section-content {
  padding: var(--spacing-lg) 0 var(--spacing-xl);
  max-width: var(--about-max-content);
  margin-left: calc(2.4em + var(--spacing-sm));
}
@media (min-width: 768px) {
  .page-about .section-content {
    max-width: 800px;
    margin-left: calc(4em + var(--spacing-md));
  }
}

/* principle cards */
.page-about .principle-cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-lg);
}
@media (min-width: 640px) {
  .page-about .principle-cards {
    grid-template-columns: repeat(3, 1fr);
  }
}
.page-about .principle-card {
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.06);
  border-radius: var(--about-radius);
  padding: var(--spacing-lg);
  box-shadow: var(--about-card-shadow);
  transition: transform var(--about-transition), box-shadow var(--about-transition);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}
.page-about .principle-card:hover {
  transform: translateY(-4px) scale(1.01);
  box-shadow: 0 6px 24px rgba(0,0,0,0.4);
  border-color: var(--about-gold);
}
.page-about .principle-card-icon {
  color: var(--about-gold);
  width: 36px;
  height: 36px;
  flex-shrink: 0;
}
.page-about .principle-card .card-title {
  font-family: var(--font-heading);
  font-weight: var(--fw-heading);
  font-size: var(--fs-heading-sm);
  color: var(--about-text-light);
  margin: 0;
}
.page-about .principle-card .card-text {
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  color: var(--about-text-muted);
  margin: 0;
}

/* boundary section */
.page-about .boundary-intro {
  margin-bottom: var(--spacing-lg);
}
.page-about .boundary-text {
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  color: var(--about-text-muted);
  margin: 0;
}
.page-about .boundary-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}
@media (min-width: 640px) {
  .page-about .boundary-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}
.page-about .boundary-item {
  background: rgba(255,255,255,0.03);
  border-left: 3px solid var(--about-gold);
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: 0 var(--about-radius) var(--about-radius) 0;
  transition: background var(--transition-fast);
}
.page-about .boundary-item:hover {
  background: rgba(255,255,255,0.07);
}
.page-about .boundary-badge {
  display: inline-block;
  font-family: var(--font-heading);
  font-weight: var(--fw-heading);
  font-size: var(--fs-caption);
  color: var(--about-gold);
  background: rgba(255,215,0,0.12);
  padding: 2px 10px;
  border-radius: 12px;
  margin-bottom: var(--spacing-sm);
  letter-spacing: 0.04em;
}
.page-about .boundary-item-title {
  font-family: var(--font-heading);
  font-weight: var(--fw-special);
  font-size: var(--fs-body);
  color: var(--about-text-light);
  margin: 0 0 var(--spacing-xs);
}
.page-about .boundary-item-text {
  font-family: var(--font-body);
  font-size: var(--fs-caption);
  line-height: 1.5;
  color: var(--about-text-muted);
  margin: 0;
}
.page-about .boundary-figure {
  margin: var(--spacing-lg) 0 0;
  text-align: center;
}
.page-about .boundary-diagram {
  display: block;
  width: 100%;
  max-width: 600px;
  height: auto;
  aspect-ratio: 2/1;
  object-fit: contain;
  background: rgba(255,255,255,0.04);
  border-radius: var(--about-radius);
  margin: 0 auto;
}
.page-about .boundary-caption {
  font-family: var(--font-caption);
  font-size: var(--fs-caption);
  color: var(--about-text-muted);
  margin-top: var(--spacing-sm);
  opacity: 0.7;
}

/* scenarios section */
.page-about .scenario-icons {
  display: flex;
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
  flex-wrap: wrap;
  justify-content: center;
}
.page-about .scenario-icon {
  display: block;
  width: 80px;
  height: 80px;
  object-fit: contain;
  background: rgba(255,255,255,0.04);
  border-radius: var(--about-radius);
  transition: transform var(--transition-fast);
}
.page-about .scenario-icon:hover {
  transform: scale(1.06);
}
.page-about .scenario-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-lg);
}
@media (min-width: 640px) {
  .page-about .scenario-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}
.page-about .scenario-card {
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.06);
  border-radius: var(--about-radius);
  padding: var(--spacing-lg);
  box-shadow: var(--about-card-shadow);
  transition: transform var(--about-transition), box-shadow var(--about-transition);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}
.page-about .scenario-card:hover {
  transform: translateY(-3px) scale(1.01);
  box-shadow: 0 6px 24px rgba(0,0,0,0.4);
  border-color: var(--about-gold);
}
.page-about .scenario-card .card-title {
  font-family: var(--font-heading);
  font-weight: var(--fw-heading);
  font-size: var(--fs-heading-sm);
  color: var(--about-text-light);
  margin: 0;
}
.page-about .scenario-card .card-text {
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  color: var(--about-text-muted);
  margin: 0;
  flex: 1 1 auto;
}
.page-about .scenario-link {
  font-family: var(--font-special);
  font-size: var(--fs-special);
  font-weight: var(--fw-special);
  color: var(--about-gold);
  text-decoration: none;
  letter-spacing: var(--ls-special);
  transition: opacity var(--transition-fast);
  align-self: flex-start;
  margin-top: var(--spacing-sm);
}
.page-about .scenario-link:hover,
.page-about .scenario-link:focus {
  opacity: 0.8;
  outline: 2px solid var(--about-gold);
  outline-offset: 2px;
}

/* faq section */
.page-about .faq-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
  margin: 0;
  padding: 0;
}
.page-about .faq-item {
  border-bottom: 1px solid rgba(0,0,0,0.07);
  padding-bottom: var(--spacing-lg);
}
.page-about .faq-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}
.page-about .faq-q {
  font-family: var(--font-heading);
  font-weight: var(--fw-special);
  font-size: var(--fs-body);
  color: var(--about-text-dark);
  margin: 0 0 var(--spacing-sm);
  padding-left: var(--spacing-md);
  border-left: 3px solid var(--about-gold);
}
.page-about .faq-a {
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  color: #2A2A2A;
  margin: 0;
  padding-left: var(--spacing-md);
}

/* reveal animation */
.page-about .reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.page-about .reveal--visible {
  opacity: 1;
  transform: translateY(0);
}
@media (prefers-reduced-motion: reduce) {
  .page-about .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

/* mobile first adjustments */
@media (max-width: 640px) {
  .page-about .framed-viewport--about {
    flex-direction: column;
    align-items: stretch;
    gap: var(--spacing-lg);
    padding: var(--spacing-lg) var(--spacing-md);
  }
  .page-about .motto-text {
    font-size: 1.6rem;
  }
  .page-about .motto-figure {
    text-align: center;
  }
  .page-about .motto-img {
    max-width: 240px;
    margin: 0 auto;
  }
  .page-about .about-section {
    padding: 0 var(--spacing-md);
  }
  .page-about .section-details {
    padding: var(--spacing-md) 0;
  }
  .page-about .section-content {
    padding: var(--spacing-md) 0;
    margin-left: 0;
  }
  .page-about .section-summary {
    align-items: center;
  }
  .page-about .section-number {
    font-size: 2rem;
    min-width: 1.8em;
  }
  .page-about .boundary-grid {
    grid-template-columns: 1fr;
  }
  .page-about .scenario-grid {
    grid-template-columns: 1fr;
  }
  .page-about .principle-cards {
    grid-template-columns: 1fr;
  }
  .page-about .scenario-icons {
    justify-content: center;
    gap: var(--spacing-md);
  }
  .page-about .boundary-diagram {
    max-width: 100%;
  }
}

@media (min-width: 641px) and (max-width: 1024px) {
  .page-about .framed-viewport--about {
    gap: var(--spacing-lg);
    padding: var(--spacing-xl) var(--spacing-md);
  }
  .page-about .motto-text {
    font-size: 2rem;
  }
  .page-about .section-content {
    max-width: 640px;
  }
  .page-about .principle-cards {
    grid-template-columns: repeat(2, 1fr);
  }
  .page-about .principle-card:last-child {
    grid-column: 1 / -1;
    max-width: 50%;
    justify-self: center;
  }
}