.page-about {
  --about-panel: rgba(13, 43, 69, 0.65);
  --about-panel-solid: #0d2b45;
  --about-shadow: 8px 8px 0 rgba(0, 0, 0, 0.3);
  --about-shadow-paper: 10px 10px 0 var(--color-text-dark);
  --about-paper: var(--color-bg-light);
  --about-ink: var(--color-text-dark);
  background:
    radial-gradient(1px 1px at 15% 22%, rgba(255, 255, 255, 0.6), transparent 50%),
    radial-gradient(1.5px 1.5px at 78% 15%, rgba(212, 175, 55, 0.5), transparent 50%),
    radial-gradient(1px 1px at 85% 70%, rgba(255, 255, 255, 0.45), transparent 50%),
    radial-gradient(1px 1px at 30% 82%, rgba(212, 175, 55, 0.4), transparent 50%),
    linear-gradient(180deg, var(--color-bg-dark) 0%, var(--color-primary) 55%, var(--color-primary-variant) 100%);
  color: var(--color-text-light);
}

.page-about [id] {
  scroll-margin-top: calc(var(--header-height) + 1.25rem);
}

.page-about img {
  max-width: 100%;
  height: auto;
}

.page-about .about-hero {
  padding: 4.5rem 0 3.5rem;
}

.page-about .about-hero__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
}

.page-about .about-hero__kicker {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.25em;
  color: var(--color-accent);
  margin-bottom: 1rem;
}

.page-about .about-hero__kicker::before {
  content: "";
  display: inline-block;
  width: 3rem;
  height: 2px;
  background: var(--color-accent);
}

.page-about .about-hero__title {
  font-family: var(--font-heading);
  font-size: clamp(2.4rem, 5.2vw, 4.2rem);
  line-height: 1.08;
  font-weight: 700;
  margin: 0 0 0.75rem;
  color: var(--color-text-light);
}

.page-about .about-hero__subtitle {
  display: block;
  font-size: clamp(1.05rem, 2vw, 1.4rem);
  font-weight: 400;
  color: var(--color-accent);
  border-left: 4px solid var(--color-accent);
  padding-left: 1rem;
  margin-bottom: 1.5rem;
}

.page-about .about-hero__desc {
  max-width: 46rem;
  font-size: 1rem;
  line-height: 1.8;
  color: rgba(245, 247, 250, 0.82);
  margin-bottom: 2rem;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.page-about .about-hero__side {
  border: 3px solid var(--color-accent);
  background: rgba(13, 43, 69, 0.55);
  box-shadow: 8px 8px 0 rgba(0, 0, 0, 0.3);
  padding: 1.5rem 1.25rem 1.25rem;
}

.page-about .about-hero__side-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.75rem;
  border-bottom: 2px solid var(--color-accent);
  padding-bottom: 0.6rem;
}

.page-about .about-hero__side-title {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.95rem;
  letter-spacing: 0.12em;
  color: var(--color-text-light);
}

.page-about .about-hero__side-count {
  font-family: var(--font-mono);
  font-size: 1.2rem;
  color: var(--color-accent);
}

.page-about .about-hero__vertical {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.3em;
  writing-mode: vertical-rl;
  color: rgba(212, 175, 55, 0.65);
  margin: -0.35rem 0 0.25rem auto;
}

.page-about .about-hero__index {
  list-style: none;
  margin: 0.75rem 0 0;
  padding: 0;
  display: grid;
  gap: 0.4rem;
}

.page-about .about-hero__index li {
  border-bottom: 1px solid rgba(244, 235, 217, 0.15);
}

.page-about .about-hero__index a {
  display: flex;
  align-items: baseline;
  gap: 0.9rem;
  padding: 0.6rem 0.2rem;
  color: var(--color-text-light);
  text-decoration: none;
  transition: color 0.2s ease, padding-left 0.2s ease;
}

.page-about .about-hero__index a span {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--color-accent);
}

.page-about .about-hero__index a:hover,
.page-about .about-hero__index a:focus-visible {
  color: var(--color-accent);
  padding-left: 0.5rem;
}

.page-about .about-story {
  background: var(--color-bg-light);
  color: var(--color-text-dark);
  border-top: 4px solid var(--color-accent);
  border-bottom: 4px solid var(--color-accent);
  padding: 4.5rem 0;
}

.page-about .about-story .section-index,
.page-about .about-story .section-title,
.page-about .about-story .section-subtitle {
  color: var(--color-text-dark);
}

.page-about .about-story__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
}

.page-about .about-story__figure {
  margin: 0;
  border: 3px solid var(--color-text-dark);
  box-shadow: 12px 12px 0 var(--color-text-dark);
  position: relative;
}

.page-about .about-story__figure::after {
  content: "FIG.01 / 2019→2025";
  position: absolute;
  right: -0.75rem;
  bottom: -2.2rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--color-text-dark);
  background: var(--color-bg-light);
  padding: 0.25rem 0.5rem;
  border: 1px solid var(--color-text-dark);
}

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

.page-about .about-story__content p {
  line-height: 1.9;
  color: var(--color-text-dark);
}

.page-about .about-story__intro {
  font-size: 1.15rem;
  font-weight: 500;
  border-left: 4px solid var(--color-text-dark);
  padding-left: 1rem;
}

.page-about .about-story__stats {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem 1.5rem;
  margin-top: 2rem;
}

.page-about .about-story__stat {
  border-top: 3px solid var(--color-text-dark);
  padding-top: 0.75rem;
}

.page-about .about-story__stat dt {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--color-mineral-gray);
}

.page-about .about-story__stat dd {
  margin: 0;
  font-family: var(--font-heading);
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-text-dark);
}

.page-about .about-timeline-section {
  padding: 5rem 0;
}

.page-about .about-timeline__banner {
  display: block;
  width: 100%;
  height: auto;
  border: 2px solid var(--color-accent);
  box-shadow: 8px 8px 0 rgba(0, 0, 0, 0.3);
  margin-bottom: 2.5rem;
}

.page-about .about-timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  position: relative;
  display: grid;
  gap: 1.5rem;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 19px;
  top: 20px;
  bottom: 20px;
  width: 2px;
  background: linear-gradient(to bottom, transparent, var(--color-accent) 4%, var(--color-accent) 96%, transparent);
}

.page-about .about-timeline__item {
  position: relative;
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 1rem;
  align-items: stretch;
}

.page-about .about-timeline__marker {
  display: block;
  width: 40px;
  height: 40px;
  position: relative;
  z-index: 1;
}

.page-about .about-timeline__card {
  border: 2px solid var(--color-accent);
  border-left-width: 4px;
  background: rgba(13, 43, 69, 0.6);
  padding: 1.2rem 1.4rem;
  box-shadow: 6px 6px 0 rgba(0, 0, 0, 0.3);
  transition: background-color 0.2s, box-shadow 0.2s, border-color 0.2s;
}

.page-about .about-timeline__item:nth-child(1) .about-timeline__card {
  border-left-color: var(--color-moss-green);
}

.page-about .about-timeline__item:nth-child(2) .about-timeline__card {
  border-left-color: var(--color-mineral-gray);
}

.page-about .about-timeline__item:nth-child(3) .about-timeline__card {
  border-left-color: var(--color-terracotta);
}

.page-about .about-timeline__card:hover,
.page-about .about-timeline__card:focus-within {
  background: rgba(13, 43, 69, 0.95);
  border-color: var(--color-accent);
  box-shadow: 10px 10px 0 var(--color-accent);
}

.page-about .about-timeline__year {
  font-family: var(--font-mono);
  font-size: 1.1rem;
  color: var(--color-accent);
  margin-bottom: 0.4rem;
}

.page-about .about-timeline__card h3 {
  margin: 0 0 0.4rem;
  font-size: 1.2rem;
  color: var(--color-text-light);
}

.page-about .about-timeline__card p {
  color: rgba(245, 247, 250, 0.78);
  line-height: 1.7;
}

.page-about .about-timeline__detail {
  border-left: 2px solid var(--color-accent);
  padding-left: 0.75rem;
  color: var(--color-mineral-gray);
  font-size: 0.9rem;
  line-height: 1.7;
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  margin: 0;
  transition: max-height 0.35s ease, opacity 0.35s ease, margin 0.35s ease;
}

.page-about .about-tech {
  padding: 5rem 0;
}

.page-about .about-tech__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

.page-about .about-tech__visual {
  border: 3px solid var(--color-accent);
  background: rgba(13, 43, 69, 0.25);
  box-shadow: 10px 10px 0 rgba(0, 0, 0, 0.3);
  padding: 1rem;
  overflow-x: auto;
}

.page-about .about-tech__svg {
  display: block;
  min-width: 480px;
  width: 100%;
  height: auto;
}

.page-about .about-tech__content p {
  color: rgba(245, 247, 250, 0.8);
  line-height: 1.8;
}

.page-about .about-tech__modules {
  list-style: none;
  margin: 2.5rem 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
}

.page-about .about-tech__module {
  border: 2px solid rgba(244, 235, 217, 0.3);
  padding: 1.1rem 0.5rem;
  text-align: center;
  color: var(--color-text-light);
  font-weight: 500;
  background: rgba(13, 43, 69, 0.25);
  transition: border-color 0.2s, transform 0.2s, background-color 0.2s;
}

.page-about .about-tech__module:hover,
.page-about .about-tech__module:focus-within {
  border-color: var(--color-accent);
  background: rgba(13, 43, 69, 0.5);
  transform: translateY(-3px);
}

.page-about .about-service {
  background: var(--color-bg-light);
  color: var(--color-text-dark);
  border-top: 4px solid var(--color-accent);
  border-bottom: 4px solid var(--color-accent);
  padding: 4.5rem 0;
}

.page-about .about-service .section-index,
.page-about .about-service .section-title,
.page-about .about-service .section-subtitle {
  color: var(--color-text-dark);
}

.page-about .about-service__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

.page-about .about-service__media {
  border: 3px solid var(--color-text-dark);
  box-shadow: 10px 10px 0 var(--color-text-dark);
  display: flex;
}

.page-about .about-service__icon {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .about-service__stats {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

.page-about .about-service__stat {
  border-top: 3px solid var(--color-text-dark);
  padding-top: 1rem;
}

.page-about .about-service__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(2rem, 4vw, 2.6rem);
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-text-dark);
}

.page-about .about-service__label {
  display: block;
  font-size: 0.95rem;
  color: var(--color-text-dark);
  line-height: 1.5;
}

.page-about .about-service__desc {
  border-left: 4px solid var(--color-text-dark);
  padding-left: 1rem;
  margin-top: 2.5rem;
  color: var(--color-text-dark);
  font-size: 1rem;
  line-height: 1.8;
}

.page-about .about-contact {
  padding: 5rem 0;
}

.page-about .about-contact__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

.page-about .about-contact__info,
.page-about .about-contact__coop {
  border: 3px solid var(--color-accent);
  background: rgba(13, 43, 69, 0.5);
  box-shadow: 8px 8px 0 rgba(0, 0, 0, 0.3);
  padding: 1.75rem;
}

.page-about .about-contact h3 {
  margin: 0 0 1rem;
  font-size: 1.35rem;
  color: var(--color-text-light);
}

.page-about .about-contact p {
  color: rgba(245, 247, 250, 0.82);
  line-height: 1.8;
}

.page-about .about-contact__list {
  list-style: none;
  margin: 1rem 0 1.5rem;
  padding: 0;
  display: grid;
  gap: 0.5rem;
}

.page-about .about-contact__item {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.7rem 0.9rem;
  background: rgba(10, 26, 47, 0.45);
}

.page-about .about-contact__item dt {
  color: var(--color-mineral-gray);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  white-space: nowrap;
}

.page-about .about-contact__item dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.95rem;
  color: var(--color-text-light);
  text-align: right;
  overflow-wrap: anywhere;
}

.page-about .about-contact__note {
  font-size: 0.95rem;
  color: var(--color-mineral-gray);
}

.page-about .about-contact__detail {
  border: 2px solid rgba(244, 235, 217, 0.25);
  margin-top: 0.85rem;
  padding: 0.1rem 0.9rem;
  transition: border-color 0.2s;
}

.page-about .about-contact__detail[open] {
  border-color: var(--color-accent);
}

.page-about .about-contact__detail summary {
  cursor: pointer;
  padding: 0.75rem 0;
  font-weight: 600;
  color: var(--color-text-light);
  list-style: none;
}

.page-about .about-contact__detail summary::-webkit-details-marker {
  display: none;
}

.page-about .about-contact__detail summary::before {
  content: "＋";
  margin-right: 0.6rem;
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: 1.1rem;
}

.page-about .about-contact__detail[open] summary::before {
  content: "—";
}

.page-about .about-contact__detail p {
  margin: 0 0 0.9rem;
  font-size: 0.95rem;
  color: rgba(245, 247, 250, 0.75);
}

.page-about .about-contact__links {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 1.5rem;
}

@media (max-width: 800px) {
  .page-about .about-timeline__detail {
    max-height: none;
    opacity: 1;
    margin-top: 0.75rem;
  }
}

@media (max-width: 400px) {
  .page-about .about-contact__item {
    flex-direction: column;
    gap: 0.2rem;
  }

  .page-about .about-contact__item dd {
    text-align: left;
  }
}

@media (min-width: 520px) {
  .page-about .about-story__stats {
    grid-template-columns: repeat(2, 1fr);
  }

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

@media (min-width: 620px) {
  .page-about .about-tech__modules {
    grid-template-columns: repeat(4, 1fr);
  }
}

@media (min-width: 801px) {
  .page-about .about-timeline__card:hover .about-timeline__detail,
  .page-about .about-timeline__card:focus-within .about-timeline__detail {
    max-height: 8rem;
    opacity: 1;
    margin-top: 0.75rem;
  }
}

@media (min-width: 900px) {
  .page-about .about-story__grid {
    grid-template-columns: 0.9fr 1.1fr;
    gap: 3.5rem;
    align-items: center;
  }

  .page-about .about-story__figure {
    order: 2;
    margin-top: 3rem;
  }

  .page-about .about-story__content {
    order: 1;
  }

  .page-about .about-tech__grid {
    grid-template-columns: 1.15fr 0.85fr;
    gap: 3.5rem;
    align-items: center;
  }

  .page-about .about-tech__visual {
    overflow-x: visible;
  }

  .page-about .about-tech__svg {
    min-width: 0;
  }

  .page-about .about-service__grid {
    grid-template-columns: 280px 1fr;
    gap: 3rem;
    align-items: center;
  }

  .page-about .about-contact__grid {
    grid-template-columns: 1fr 1fr;
    gap: 2.5rem;
    align-items: start;
  }
}

@media (min-width: 960px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1fr) 340px;
    gap: 3.5rem;
    align-items: start;
  }
}