.page-about {
  --about-red: var(--color-accent);
  --about-red-dark: var(--color-accent-dark);
  --about-gold: var(--color-gold);
  --about-ink: var(--color-bg-dark);
  --about-rock: var(--color-bg-rock);
  --about-paper: var(--color-bg);
  --about-sand: var(--color-sand);
  --about-mono: var(--font-mono);
  background: var(--about-paper);
  color: var(--color-text);
  overflow-x: clip;
}

.pg-about-hero {
  position: relative;
  background: var(--about-ink);
  color: var(--color-text-on-dark);
  padding: calc(var(--header-h) + 32px) 0 0;
  overflow: hidden;
}
.pg-about-hero::before {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 55%;
  height: 70%;
  background: var(--about-red);
  clip-path: polygon(28% 0, 100% 0, 100% 100%, 0 100%);
  opacity: 0.22;
  pointer-events: none;
}
.pg-about-hero .breadcrumbs {
  margin-bottom: 32px;
}
.pg-about-hero .breadcrumbs a {
  color: var(--color-text-on-dark);
  opacity: 0.7;
}
.pg-about-hero .breadcrumbs .sep {
  color: var(--about-gold);
  margin: 0 8px;
}
.pg-about-hero__grid {
  display: grid;
  gap: 40px;
  padding-bottom: 48px;
  position: relative;
  z-index: 1;
}
.pg-about-hero__title {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: clamp(2rem, 6vw, 4.5rem);
  line-height: 1.02;
  letter-spacing: -0.02em;
  margin: 16px 0 20px;
}
.pg-about-hero__lead {
  font-size: var(--font-body-size);
  line-height: var(--font-body-lh);
  color: var(--color-text-on-dark);
  opacity: 0.85;
  max-width: 54ch;
  margin: 0 0 28px;
}
.pg-about-hero__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 24px;
}
.pg-about-hero__meta-item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--color-text-on-dark);
  opacity: 0.75;
}
.pg-about-hero__meta-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--about-gold);
  flex-shrink: 0;
}
.pg-about-hero__panel {
  background: var(--about-paper);
  color: var(--color-text);
  border: var(--border-thick) solid var(--about-red);
  box-shadow: 8px 8px 0 var(--color-accent-dark);
  padding: 24px;
  position: relative;
  max-width: 260px;
}
.pg-about-hero__panel::after {
  content: "";
  position: absolute;
  bottom: -12px;
  right: 16px;
  width: 40px;
  height: 6px;
  background: var(--about-gold);
}
.pg-about-hero__panel-label {
  display: block;
  font-family: var(--about-mono);
  font-size: 0.75rem;
  color: var(--color-text-secondary);
  margin-bottom: 4px;
}
.pg-about-hero__panel-version {
  display: block;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 3.5rem;
  line-height: 1;
  color: var(--about-red);
}
.pg-about-hero__panel-note {
  display: block;
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  margin: 8px 0 16px;
}
.pg-about-hero__panel-link {
  display: inline-block;
  font-weight: 600;
  font-size: 0.875rem;
  color: var(--color-text);
  text-underline-offset: 4px;
}
.pg-about-hero__panel-link:hover {
  color: var(--about-red);
}
.pg-about-hero__cover {
  border-top: var(--border-thick) solid var(--about-gold);
  position: relative;
}
.pg-about-hero__img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  aspect-ratio: 1400 / 600;
}

.pg-about-method,
.pg-about-versions {
  padding: 56px 0;
}
.pg-about-method__head,
.pg-about-scale__head,
.pg-about-versions__head,
.pg-about-taxonomy__head {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 40px;
}
.pg-about-method__head-index,
.pg-about-scale__head-index,
.pg-about-versions__head-index,
.pg-about-taxonomy__head-index {
  font-family: var(--about-mono);
  font-size: 0.875rem;
  font-weight: 600;
  background: var(--about-red);
  color: #fff;
  padding: 6px 12px;
  clip-path: polygon(0 0, 100% 0, calc(100% - 10px) 100%, 0 100%);
  flex-shrink: 0;
}
.pg-about-method__head h2,
.pg-about-scale__head h2,
.pg-about-versions__head h2,
.pg-about-taxonomy__head h2 {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: clamp(1.75rem, 4vw, 3rem);
  line-height: 1.1;
  margin: 0 0 6px;
}
.pg-about-method__head-desc,
.pg-about-scale__head-desc,
.pg-about-versions__head-desc,
.pg-about-taxonomy__head-desc {
  color: var(--color-text-secondary);
  font-size: var(--font-body-size);
  margin: 0;
}
.pg-about-method__flow {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  border-top: var(--border-thick) solid var(--color-sand);
}
.pg-about-method__step {
  position: relative;
  padding: 28px 8px 28px 0;
  border-bottom: var(--border-thin) solid var(--color-sand);
}
.pg-about-method__step-num {
  display: block;
  font-family: var(--about-mono);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--about-red);
  margin-bottom: 8px;
}
.pg-about-method__step h3 {
  font-family: var(--font-heading);
  font-weight: 650;
  font-size: 1.125rem;
  margin: 0 0 8px;
}
.pg-about-method__step p {
  font-size: var(--font-body-size);
  color: var(--color-text-secondary);
  line-height: var(--font-body-lh);
  margin: 0;
  max-width: 44ch;
}
.pg-about-method__step--hot {
  background: linear-gradient(90deg, rgba(181, 89, 59, 0.08), transparent);
  border-left: var(--border-thick) solid var(--about-red);
  padding-left: 16px;
}

.pg-about-scale {
  padding: 56px 0;
}
.pg-about-scale .pg-about-scale__head h2 {
  color: var(--color-text-on-dark);
}
.pg-about-scale .pg-about-scale__head-desc {
  color: var(--color-text-on-dark);
  opacity: 0.7;
}
.pg-about-scale__stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-bottom: 48px;
}
.pg-about-scale__stat {
  background: var(--about-ink);
  border: var(--border-thick) solid var(--about-rock);
  padding: 20px 16px;
  transition: transform 0.3s var(--ease-out), box-shadow 0.3s var(--ease-out);
}
.pg-about-scale__stat:hover {
  transform: translate(-3px, -3px);
  box-shadow: 6px 6px 0 var(--about-gold);
}
.pg-about-scale__stat-value {
  display: block;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: clamp(2.5rem, 6vw, 4rem);
  line-height: 1;
  color: var(--about-gold);
}
.pg-about-scale__stat-value em {
  font-style: normal;
  font-size: 0.55em;
  color: var(--color-text-on-dark);
  margin-left: 2px;
}
.pg-about-scale__stat-label {
  display: block;
  font-size: 0.8125rem;
  color: var(--color-text-on-dark);
  opacity: 0.75;
  margin-top: 8px;
}
.pg-about-scale__bottom {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
}
.pg-about-scale__fact p {
  font-size: var(--font-body-size);
  line-height: var(--font-body-lh);
  color: var(--color-text-on-dark);
  opacity: 0.85;
  margin: 0 0 16px;
  max-width: 50ch;
}
.pg-about-scale__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 20px;
}
.pg-about-scale__tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255, 255, 255, 0.08);
  border: var(--border-thin) solid rgba(255, 255, 255, 0.22);
  padding: 10px 14px;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--color-text-on-dark);
  cursor: default;
  transition: border-color 0.3s, background 0.3s;
}
.pg-about-scale__tag:hover,
.pg-about-scale__tag:focus-within,
.pg-about-scale__tag:focus {
  border-color: var(--about-gold);
  background: rgba(199, 154, 59, 0.15);
}
.pg-about-scale__tag-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--about-gold);
  flex-shrink: 0;
}
.pg-about-scale__tag-hint {
  font-style: normal;
  font-family: var(--about-mono);
  font-size: 0.7rem;
  opacity: 0.7;
}
.pg-about-scale__visual {
  position: relative;
}
.pg-about-scale__img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 1000 / 700;
  object-fit: cover;
  border: var(--border-thick) solid var(--about-ink);
  box-shadow: 8px 8px 0 rgba(0, 0, 0, 0.25);
}

.pg-about-versions__timeline {
  list-style: none;
  margin: 0 0 40px;
  padding: 0;
  position: relative;
}
.pg-about-versions__item {
  position: relative;
  padding-left: 28px;
  border-left: var(--border-thick) solid var(--color-sand);
  padding-bottom: 28px;
}
.pg-about-versions__item:last-child {
  padding-bottom: 0;
}
.pg-about-versions__item::before {
  content: "";
  position: absolute;
  left: -8px;
  top: 6px;
  width: 12px;
  height: 12px;
  border: var(--border-thick) solid var(--color-sand);
  background: var(--about-paper);
  border-radius: 50%;
}
.pg-about-versions__item--current::before {
  background: var(--about-gold);
  border-color: var(--about-gold);
}
.pg-about-versions__ver {
  display: inline-block;
  font-family: var(--about-mono);
  font-weight: 700;
  font-size: 0.75rem;
  background: var(--about-red);
  color: #fff;
  padding: 4px 10px;
  clip-path: polygon(0 0, 100% 0, calc(100% - 8px) 100%, 0 100%);
  margin-bottom: 8px;
}
.pg-about-versions__item--current .pg-about-versions__ver {
  background: var(--about-gold);
  color: var(--about-ink);
}
.pg-about-versions__node h3 {
  font-family: var(--font-heading);
  font-weight: 650;
  font-size: 1.125rem;
  margin: 0 0 8px;
}
.pg-about-versions__node p {
  font-size: var(--font-body-size);
  color: var(--color-text-secondary);
  line-height: var(--font-body-lh);
  margin: 0;
  max-width: 40ch;
}
.pg-about-versions__img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 1200 / 800;
  object-fit: cover;
  border: var(--border-thick) solid var(--about-ink);
  box-shadow: var(--shadow-dark);
  margin-top: 36px;
}

.pg-about-taxonomy {
  padding: 56px 0;
}
.pg-about-taxonomy .pg-about-taxonomy__head h2 {
  color: var(--color-text-on-dark);
}
.pg-about-taxonomy .pg-about-taxonomy__head-desc {
  color: var(--color-text-on-dark);
  opacity: 0.7;
}
.pg-about-taxonomy__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}
.pg-about-taxonomy__card {
  position: relative;
  background: rgba(255, 255, 255, 0.04);
  border: var(--border-thin) solid rgba(255, 255, 255, 0.18);
  padding: 24px 20px;
  overflow: hidden;
  transition: border-color 0.3s, background 0.3s, transform 0.3s var(--ease-out);
}
.pg-about-taxonomy__card:hover {
  border-color: var(--about-gold);
  background: rgba(255, 255, 255, 0.08);
  transform: translate(-2px, -2px);
}
.pg-about-taxonomy__index {
  position: absolute;
  top: -10px;
  right: 8px;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 6rem;
  line-height: 1;
  color: rgba(255, 255, 255, 0.06);
  pointer-events: none;
}
.pg-about-taxonomy__card h3 {
  font-family: var(--font-heading);
  font-weight: 650;
  font-size: 1.125rem;
  color: var(--color-text-on-dark);
  margin: 0 0 10px;
  position: relative;
  z-index: 1;
}
.pg-about-taxonomy__card p {
  font-size: var(--font-body-size);
  color: var(--color-text-on-dark);
  opacity: 0.78;
  line-height: var(--font-body-lh);
  margin: 0 0 14px;
  position: relative;
  z-index: 1;
  max-width: 36ch;
}
.pg-about-taxonomy__link {
  display: inline-block;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--about-gold);
  text-decoration: none;
  position: relative;
  z-index: 1;
}
.pg-about-taxonomy__link:hover {
  text-decoration: underline;
  text-underline-offset: 4px;
}
.pg-about-taxonomy__card--cta {
  background: var(--about-red);
  border-color: var(--about-red);
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.pg-about-taxonomy__card--cta h3 {
  font-size: 1.375rem;
}
.pg-about-taxonomy__card--cta p {
  opacity: 0.9;
}
.pg-about-taxonomy__card--cta .btn {
  align-self: flex-start;
  margin-top: 6px;
}

.pg-about-outro {
  padding: 64px 0 80px;
}
.pg-about-outro__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 24px;
  text-align: center;
}
.pg-about-outro__text {
  font-family: var(--font-heading);
  font-weight: 650;
  font-size: clamp(1.25rem, 3vw, 2rem);
  line-height: 1.3;
  margin: 0;
}

@media (min-width: 768px) {
  .pg-about-hero {
    padding-top: calc(var(--header-h) + 56px);
  }
  .pg-about-hero__grid {
    grid-template-columns: 1fr 260px;
    align-items: start;
    gap: 48px;
  }
  .pg-about-method__flow {
    grid-template-columns: 1fr 1fr;
    border-left: var(--border-thick) solid var(--color-sand);
  }
  .pg-about-method__step {
    padding: 28px 24px;
    border-right: var(--border-thin) solid var(--color-sand);
  }
  .pg-about-method__step--hot {
    background: linear-gradient(90deg, rgba(181, 89, 59, 0.08), transparent);
    border-left: var(--border-thick) solid var(--about-red);
    padding-left: 24px;
  }
  .pg-about-scale__stats {
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
  }
  .pg-about-scale__bottom {
    grid-template-columns: 1fr 1fr;
    align-items: center;
  }
  .pg-about-taxonomy__grid {
    grid-template-columns: 1fr 1fr;
    gap: 20px;
  }
  .pg-about-taxonomy__card {
    padding: 32px 28px;
  }
  .pg-about-taxonomy__card--cta {
    grid-column: 1 / -1;
  }
}

@media (min-width: 1024px) {
  .pg-about-method {
    padding: 96px 0;
  }
  .pg-about-method__flow {
    grid-template-columns: repeat(4, 1fr);
  }
  .pg-about-method__step {
    border-right: var(--border-thin) solid var(--color-sand);
  }
  .pg-about-method__step:last-child {
    border-right: none;
  }
  .pg-about-versions__timeline {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0;
  }
  .pg-about-versions__item,
  .pg-about-versions__item:last-child {
    padding-left: 0;
    padding-right: 24px;
    border-left: none;
    border-top: var(--border-thick) solid var(--color-sand);
    padding-top: 28px;
  }
  .pg-about-versions__item::before {
    left: 0;
    top: -8px;
  }
  .pg-about-versions__node {
    padding-right: 16px;
  }
  .pg-about-taxonomy {
    padding: 96px 0;
  }
  .pg-about-taxonomy__grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .pg-about-taxonomy__card--cta {
    grid-column: auto;
  }
  .pg-about-outro {
    padding: 80px 0 100px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .pg-about-scale__stat,
  .pg-about-taxonomy__card {
    transition: none;
  }
  .pg-about-scale__stat:hover,
  .pg-about-taxonomy__card:hover {
    transform: none;
  }
}