.page-about {
  --about-line: rgba(0, 168, 107, 0.28);
  --about-card-radius: 1.25rem;
  background: var(--primary-background);
  color: var(--primary-text);
  line-height: 1.75;
  overflow-x: hidden;
}

.page-about__hero {
  position: relative;
  padding: 2rem 0 0;
  overflow: hidden;
  background:
    linear-gradient(135deg, rgba(0, 168, 107, 0.12) 0%, rgba(247, 247, 247, 0) 42%),
    var(--primary-background);
}

.page-about__hero::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 44%;
  height: 100%;
  background: linear-gradient(160deg, var(--brand) 0%, var(--brand-dark) 100%);
  clip-path: polygon(18% 0, 100% 0, 100% 100%, 0 100%);
  opacity: 0.08;
  z-index: 0;
}

.page-about__hero .container {
  position: relative;
  z-index: 1;
}

.page-about__hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
  padding: 2.5rem 0 3.25rem;
  align-items: center;
}

.page-about__hero-copy h1 {
  font-family: var(--font-heading);
  font-size: clamp(2.25rem, 7vw, 4.5rem);
  font-weight: 300;
  line-height: 1.1;
  letter-spacing: 0.02em;
  margin: 0.75rem 0 1rem;
}

.page-about__hero-dot {
  color: var(--brand);
}

.page-about__hero-copy .lead {
  font-size: 1.05rem;
  color: var(--secondary-text);
  max-width: 42ch;
  margin: 0;
}

.page-about__hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.page-about__hero-note {
  margin-top: 1.25rem;
  font-size: 0.875rem;
  color: var(--secondary-text);
  border-left: 3px solid var(--accent);
  padding-left: 0.75rem;
}

.page-about__hero-visual {
  position: relative;
  min-height: 220px;
  display: grid;
  place-items: center;
}

.page-about__hero-svg {
  width: 100%;
  max-width: 380px;
  height: auto;
}

.page-about__hero-badge {
  position: absolute;
  left: 0;
  top: 10%;
  background: var(--glass-white);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-md);
  border-radius: 1rem;
  padding: 0.6rem 1rem;
  font-family: var(--font-heading);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--brand-dark);
}

.page-about__hero-badge--alt {
  left: auto;
  right: 0;
  top: auto;
  bottom: 12%;
  color: var(--accent);
}

.page-about__section-intro {
  padding-top: 2.5rem;
}

.page-about__chapter {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  padding-bottom: 3rem;
}

.page-about__chapter-index {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
}

.page-about__chapter-num {
  font-family: var(--font-heading);
  font-size: 3rem;
  font-weight: 300;
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1px var(--brand);
  display: block;
}

.page-about__chapter-index h2,
.page-about__scale-copy h2,
.page-about__archive-head h2,
.page-about__partner-copy h2,
.page-about .section-header h2 {
  font-family: var(--font-heading);
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: 400;
  letter-spacing: 0.04em;
  line-height: 1.2;
  margin: 0.25rem 0 0.5rem;
}

.page-about__chapter-body {
  font-size: 1rem;
}

.page-about__chapter-body p + p {
  margin-top: 1rem;
}

.page-about__lead-copy {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 500;
  color: var(--primary-text);
  margin: 0 0 1rem;
}

.page-about .glass-panel {
  margin-top: 1.5rem;
}

.page-about__intro-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.page-about__intro-links a {
  color: var(--brand-dark);
  font-weight: 600;
  text-decoration: underline;
  text-underline-offset: 4px;
  text-decoration-color: rgba(0, 168, 107, 0.35);
}

.page-about__section--milestones {
  background: var(--content-background);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
  padding: 3rem 0;
}

.page-about .section-header {
  margin-bottom: 2rem;
}

.page-about__milestone-media {
  margin-bottom: 2.5rem;
  border-radius: 1.5rem;
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.page-about__milestone-img,
.page-about__scale-img,
.page-about__partner-img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about__timeline {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about__tl-item {
  display: grid;
  grid-template-columns: 4.5rem 1.75rem 1fr;
  gap: 0.75rem;
  padding-bottom: 2.5rem;
  position: relative;
}

.page-about__tl-item::before {
  content: "";
  position: absolute;
  left: 6.125rem;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, var(--about-line), var(--about-line) 80%, transparent 100%);
}

.page-about__tl-item:last-child {
  padding-bottom: 0;
}

.page-about__tl-item:last-child::before {
  background: linear-gradient(to bottom, var(--about-line), transparent 70%);
}

.page-about__tl-meta {
  font-family: var(--font-heading);
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--brand-dark);
  text-align: right;
  line-height: 1.4;
  padding-top: 1rem;
}

.page-about__tl-track {
  position: relative;
  display: flex;
  justify-content: center;
  z-index: 1;
}

.page-about__tl-dot {
  width: 1rem;
  height: 1rem;
  border-radius: 50%;
  background: var(--brand);
  border: 3px solid var(--content-background);
  box-shadow: 0 0 0 2px var(--brand);
  margin-top: 1.35rem;
}

.page-about__tl-card {
  background: var(--glass-white);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(0, 168, 107, 0.16);
  border-radius: 1.25rem;
  padding: 1.25rem 1.375rem;
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.25s ease, transform 0.25s ease;
}

.page-about__tl-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.page-about__tl-card h3 {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 600;
  margin: 0 0 0.5rem;
  color: var(--brand-dark);
}

.page-about__tl-card p {
  margin: 0;
  font-size: 0.9375rem;
  color: var(--secondary-text);
}

.page-about__tl-more {
  margin-top: 0.75rem;
  border-top: 1px dashed var(--border-color);
  padding-top: 0.625rem;
}

.page-about__tl-more summary {
  cursor: pointer;
  font-size: 0.8125rem;
  color: var(--brand-dark);
  font-weight: 600;
  list-style: none;
}

.page-about__tl-more summary::-webkit-details-marker {
  display: none;
}

.page-about__tl-more summary::before {
  content: "+";
  color: var(--accent);
  margin-right: 0.375rem;
  font-weight: 700;
}

.page-about__tl-more[open] summary::before {
  content: "–";
}

.page-about__tl-more p {
  margin: 0.5rem 0 0;
}

.page-about__scale-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  padding: 3rem 0;
}

.page-about__scale-copy img {
  margin-top: 1.5rem;
  border-radius: 1.25rem;
  box-shadow: var(--shadow-sm);
}

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

.page-about__stat {
  background: var(--content-background);
  border: 1px solid var(--border-color);
  border-radius: 1.25rem;
  padding: 1.375rem 1.125rem;
  position: relative;
  overflow: hidden;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.page-about__stat::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 3px;
  background: var(--brand);
  transform: scaleX(0.2);
  transform-origin: left;
  transition: transform 0.3s ease;
}

.page-about__stat:last-child {
  background: linear-gradient(180deg, rgba(255, 107, 53, 0.06), var(--content-background) 50%);
}

.page-about__stat:last-child::before {
  background: var(--accent);
}

.page-about__stat:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.page-about__stat:hover::before {
  transform: scaleX(1);
}

.page-about__stat-num {
  display: block;
  font-family: var(--font-heading);
  font-size: 1.625rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--primary-text);
}

.page-about__stat-label {
  display: block;
  margin-top: 0.25rem;
  font-size: 0.8125rem;
  color: var(--secondary-text);
}

.page-about__section--versions {
  background: var(--primary-background);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
  padding: 3rem 0;
}

.page-about__versions {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.page-about__version-card {
  background: var(--content-background);
  border-radius: 1.5rem;
  padding: 1.5rem;
  border: 1px solid var(--border-color);
  border-top: 4px solid var(--brand);
  box-shadow: var(--shadow-sm);
  position: relative;
  transition: box-shadow 0.25s ease, transform 0.25s ease;
}

.page-about__version-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.page-about__version-card--current {
  border-top-color: var(--accent);
}

.page-about__version-head {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
}

.page-about__version-head h3 {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 600;
  margin: 0;
}

.page-about__version-code {
  font-family: var(--font-heading);
  font-size: 0.9375rem;
  font-weight: 800;
  color: var(--brand);
  letter-spacing: 0.08em;
  background: rgba(0, 168, 107, 0.1);
  border-radius: 0.5rem;
  padding: 0.2rem 0.6rem;
}

.page-about__version-card--current .page-about__version-code {
  color: var(--accent);
  background: rgba(255, 107, 53, 0.1);
}

.page-about__version-card > p {
  font-size: 0.9375rem;
  color: var(--secondary-text);
  margin: 0 0 0.75rem;
}

.page-about .qa-panel {
  display: block;
}

.page-about__version-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  border: none;
  background: none;
  padding: 0;
  font: inherit;
  font-size: 0.875rem;
  color: var(--brand-dark);
  font-weight: 600;
  cursor: pointer;
}

.page-about__version-toggle::after {
  content: "+";
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--accent);
  transition: transform 0.25s ease;
}

.page-about__version-card[data-open] .page-about__version-toggle::after {
  transform: rotate(45deg);
}

.page-about__version-panel {
  margin-top: 0.75rem;
}

.page-about__version-panel-inner {
  background: var(--primary-background);
  border-radius: 0.875rem;
  padding: 1rem 1.125rem;
  font-size: 0.875rem;
  color: var(--secondary-text);
}

.page-about__version-panel-inner ul {
  margin: 0;
  padding-left: 1rem;
  display: grid;
  gap: 0.375rem;
}

.page-about__archive {
  padding: 3rem 0;
}

.page-about__archive-head .lead,
.page-about__partner-copy .lead {
  color: var(--secondary-text);
}

.page-about__archive-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
  margin-top: 2rem;
}

.page-about__archive-card {
  background: var(--content-background);
  border: 1px solid var(--border-color);
  border-radius: 1.5rem;
  padding: 1.625rem;
  border-top: 4px solid var(--brand);
}

.page-about__archive-card--member {
  border-top-color: var(--accent);
  background: linear-gradient(180deg, rgba(255, 107, 53, 0.04), var(--content-background) 40%);
}

.page-about__archive-card h3 {
  font-family: var(--font-heading);
  font-size: 1.375rem;
  font-weight: 600;
  margin: 0.75rem 0 0.5rem;
}

.page-about__archive-card p {
  font-size: 0.9375rem;
  color: var(--secondary-text);
  margin: 0 0 1rem;
}

.page-about__archive-card ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.5rem;
}

.page-about__archive-card li {
  padding-left: 1.25rem;
  position: relative;
  font-size: 0.875rem;
  color: var(--primary-text);
}

.page-about__archive-card li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.5rem;
  width: 0.5rem;
  height: 0.5rem;
  border-radius: 50%;
  background: var(--brand);
}

.page-about__archive-card--member li::before {
  background: var(--accent);
}

.page-about__archive-note {
  margin-top: 1.5rem;
  font-size: 0.875rem;
  color: var(--secondary-text);
  background: var(--glass-white);
  border: 1px solid var(--border-color);
  border-radius: 1rem;
  padding: 0.875rem 1rem;
}

.page-about__section--partner {
  background: var(--content-background);
  padding: 3rem 0;
}

.page-about__partner-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  align-items: start;
}

.page-about__partner-block {
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--border-color);
}

.page-about__partner-block h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  margin: 0 0 0.375rem;
  color: var(--brand-dark);
}

.page-about__partner-block p {
  font-size: 0.9375rem;
  color: var(--secondary-text);
  margin: 0;
}

.page-about__partner-media {
  display: grid;
  gap: 1.25rem;
}

.page-about__partner-img {
  border-radius: 1.5rem;
  box-shadow: var(--shadow-md);
}

@media (min-width: 768px) {
  .page-about__hero {
    padding-top: 2.5rem;
  }

  .page-about__hero-grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    gap: 3rem;
  }

  .page-about__chapter {
    grid-template-columns: 220px 1fr;
    gap: 2.5rem;
  }

  .page-about__scale-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 3rem;
    align-items: center;
  }

  .page-about__scale-stats {
    gap: 1.25rem;
  }

  .page-about__stat-num {
    font-size: 2rem;
  }

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

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

  .page-about__partner-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.85fr);
    gap: 3rem;
  }
}

@media (min-width: 1100px) {
  .page-about__versions {
    grid-template-columns: repeat(4, 1fr);
  }
}