.page-about {
  background-color: var(--color-bg);
}

.page-about .about-hero {
  position: relative;
  padding-top: var(--space-4);
  overflow: hidden;
  border-bottom: 1px solid var(--color-border);
}

.page-about .about-hero__geo {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  pointer-events: none;
}

.page-about .about-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  gap: var(--space-3);
}

.page-about .about-hero__content {
  position: relative;
}

.page-about .about-hero__lead {
  color: var(--color-text-secondary);
  line-height: 1.7;
  max-width: 46em;
  margin-top: var(--space-2);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-3);
}

.page-about .about-hero__meta {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-2);
  margin-top: var(--space-3);
}

.page-about .hero-meta__item {
  border-left: 2px solid var(--color-accent-green);
  padding-left: var(--space-2);
}

.page-about .hero-meta__item:nth-child(2) {
  border-left-color: var(--color-accent-blue);
}

.page-about .hero-meta__item:nth-child(3) {
  border-left-color: var(--color-accent-orange);
}

.page-about .hero-meta__num {
  font-family: var(--font-mono);
  font-size: 28px;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1;
}

.page-about .hero-meta__unit {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--color-text-secondary);
  margin-left: 2px;
}

.page-about .hero-meta__label {
  display: block;
  font-size: 13px;
  color: var(--color-text-secondary);
  margin-top: var(--space-1);
}

.page-about .about-hero__img-wrap {
  position: relative;
  z-index: 1;
  margin-top: var(--space-4);
  border: 1px solid var(--color-border);
  overflow: hidden;
}

.page-about .about-hero__img {
  width: 100%;
  height: auto;
  display: block;
}

.page-about .about-origin {
  padding: var(--space-5) var(--space-1);
}

.page-about .about-origin__grid {
  display: grid;
  gap: var(--space-4);
}

.page-about .about-origin__mark {
  position: relative;
  display: grid;
  align-content: start;
  gap: var(--space-1);
  padding: var(--space-3);
  background: var(--color-panel);
  border: 1px solid var(--color-border);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 20px), calc(100% - 20px) 100%, 0 100%);
}

.page-about .about-origin__mark::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(0, 255, 136, 0.10) 0%, transparent 50%);
  pointer-events: none;
}

.page-about .about-origin__mark-num {
  font-family: var(--font-mono);
  font-size: 40px;
  font-weight: 700;
  color: var(--color-accent-green);
  line-height: 1;
}

.page-about .about-origin__mark-label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--color-accent-blue);
}

.page-about .about-origin__mark-text {
  font-size: 13px;
  color: var(--color-text-secondary);
  line-height: 1.5;
}

.page-about .about-origin__lead {
  font-family: var(--font-heading);
  font-size: 28px;
  font-style: italic;
  color: var(--color-text);
  line-height: 1.3;
  margin: var(--space-2) 0;
}

.page-about .about-origin__main p {
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.page-about .about-origin__list {
  list-style: none;
  margin: var(--space-3) 0 0;
  padding: 0;
  display: grid;
  gap: var(--space-2);
}

.page-about .about-origin__list li {
  position: relative;
  padding-left: var(--space-3);
  color: var(--color-text-secondary);
  line-height: 1.6;
}

.page-about .about-origin__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.6em;
  width: 12px;
  height: 2px;
  background: var(--color-accent-green);
}

.page-about .about-timeline {
  padding: var(--space-5) var(--space-1);
  border-top: 1px solid var(--color-border);
}

.page-about .about-timeline__header {
  max-width: 720px;
}

.page-about .about-timeline__header p:last-child {
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.page-about .about-timeline__list {
  list-style: none;
  margin: var(--space-4) 0 0;
  padding: 0;
  position: relative;
}

.page-about .about-timeline__list::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 0;
  bottom: 0;
  width: 1px;
  background: linear-gradient(180deg, var(--color-accent-green) 0%, var(--color-accent-blue) 60%, transparent 100%);
}

.page-about .timeline-node {
  position: relative;
  padding-left: var(--space-4);
  margin-bottom: var(--space-3);
}

.page-about .timeline-node__dot {
  position: absolute;
  left: 4px;
  top: 8px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--color-accent-green);
  box-shadow: 0 0 0 4px rgba(0, 255, 136, 0.16);
}

.page-about .timeline-node__card {
  background: var(--color-panel);
  border: 1px solid var(--color-border);
  border-left: 2px solid var(--color-accent-blue);
  padding: var(--space-3);
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.page-about .timeline-node__card:hover {
  transform: translateY(-2px);
  border-color: var(--color-accent-green);
}

.page-about .timeline-node__version {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--color-accent-blue);
  border: 1px solid rgba(0, 191, 255, 0.3);
  padding: 2px 8px;
}

.page-about .timeline-node__card h3 {
  font-family: var(--font-heading);
  font-size: 24px;
  font-style: italic;
  margin: var(--space-1) 0;
}

.page-about .timeline-node__card p {
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin: 0;
}

.page-about .about-timeline__foot {
  margin-top: var(--space-4);
  border: 1px solid var(--color-border);
  overflow: hidden;
}

.page-about .about-timeline__img {
  width: 100%;
  height: auto;
  display: block;
}

.page-about .about-tech {
  padding: var(--space-5) var(--space-1);
  border-top: 1px solid var(--color-border);
}

.page-about .about-tech__header {
  max-width: 760px;
}

.page-about .about-tech__header p:last-child {
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.page-about .about-tech__grid {
  display: grid;
  gap: var(--space-4);
  margin-top: var(--space-4);
}

.page-about .about-tech__topo {
  position: relative;
  border: 1px solid var(--color-border);
  overflow: hidden;
}

.page-about .about-tech__img {
  width: 100%;
  height: auto;
  display: block;
}

.page-about .about-tech__info {
  display: grid;
  gap: var(--space-2);
  align-content: start;
}

.page-about .tech-item {
  border: 1px solid var(--color-border);
  border-left: 3px solid var(--color-accent-green);
  background: var(--color-panel);
  padding: var(--space-3);
}

.page-about .tech-item:nth-child(2) {
  border-left-color: var(--color-accent-blue);
}

.page-about .tech-item:nth-child(3) {
  border-left-color: var(--color-accent-orange);
}

.page-about .tech-item__num {
  font-family: var(--font-mono);
  font-size: 32px;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1;
}

.page-about .tech-item__unit {
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--color-text-secondary);
  margin-left: 4px;
}

.page-about .tech-item__label {
  display: block;
  font-size: 14px;
  color: var(--color-text-secondary);
  margin-top: var(--space-1);
}

.page-about .tech-item--note {
  border-left-color: var(--color-border);
}

.page-about .tech-item--note p {
  margin: 0;
  color: var(--color-text-secondary);
  line-height: 1.6;
  font-size: 14px;
}

.page-about .about-principles {
  padding: var(--space-5) var(--space-1);
  border-top: 1px solid var(--color-border);
}

.page-about .about-principles__header {
  max-width: 720px;
}

.page-about .about-principles__header p:last-child {
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.page-about .about-principles__grid {
  display: grid;
  gap: var(--space-3);
  margin-top: var(--space-4);
}

.page-about .principle-card {
  position: relative;
  border: 1px solid var(--color-border);
  background: var(--color-panel);
  padding: var(--space-4) var(--space-3) var(--space-3);
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.page-about .principle-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
}

.page-about .principle-card--green::before {
  background: var(--color-accent-green);
}

.page-about .principle-card--blue::before {
  background: var(--color-accent-blue);
}

.page-about .principle-card--orange::before {
  background: var(--color-accent-orange);
}

.page-about .principle-card:hover {
  transform: translateY(-2px);
  border-color: var(--color-accent-green);
}

.page-about .principle-card__index {
  position: absolute;
  top: var(--space-2);
  right: var(--space-2);
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 700;
  color: var(--color-text-secondary);
  opacity: 0.45;
}

.page-about .principle-card h3 {
  font-family: var(--font-heading);
  font-size: 26px;
  font-style: italic;
  margin: 0 0 var(--space-1);
}

.page-about .principle-card p {
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin: 0;
}

.page-about .about-more {
  padding: var(--space-5) var(--space-1);
  border-top: 1px solid var(--color-border);
}

.page-about .about-more__grid {
  display: grid;
  gap: var(--space-2);
}

.page-about .about-more__card {
  display: grid;
  gap: var(--space-1);
  padding: var(--space-3);
  background: var(--color-panel);
  border: 1px solid var(--color-border);
  color: var(--color-text);
  text-decoration: none;
  position: relative;
  transition: transform var(--transition-fast), border-color var(--transition-fast);
  clip-path: polygon(0 0, calc(100% - 16px) 0, 100% 16px, 100% 100%, 0 100%);
}

.page-about .about-more__card:hover,
.page-about .about-more__card:focus-visible {
  transform: translateY(-2px);
  border-color: var(--color-accent-green);
  outline: none;
}

.page-about .about-more__card strong {
  font-family: var(--font-heading);
  font-size: 24px;
  font-style: italic;
}

.page-about .about-more__card span {
  color: var(--color-text-secondary);
  font-size: 14px;
  line-height: 1.5;
}

.page-about .about-more__num {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--color-accent-blue);
}

@media (min-width: 768px) {
  .page-about .about-hero__grid {
    grid-template-columns: 3fr 2fr;
    align-items: end;
  }

  .page-about .about-hero__meta {
    margin-top: 0;
  }

  .page-about .about-timeline__list {
    margin-left: var(--space-2);
  }

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

@media (min-width: 1024px) {
  .page-about .about-origin__grid {
    grid-template-columns: 240px 1fr;
    gap: var(--space-5);
  }

  .page-about .about-origin__aside {
    position: sticky;
    top: calc(var(--header-height) + var(--space-3));
    align-self: start;
  }

  .page-about .about-tech__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: var(--space-5);
  }

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

  .page-about .about-timeline__list {
    margin-left: var(--space-3);
  }
}