.page-about {
  --about-gold: #D4AF37;
  --about-blue: #00D4FF;
  --about-wine: #6B1D2A;
  --about-indigo: #3B2B5C;
  --about-bg-soft: rgba(255, 255, 255, 0.03);
  --about-line: rgba(255, 255, 255, 0.12);
  --about-gold-soft: rgba(212, 175, 55, 0.16);
  --about-blue-soft: rgba(0, 212, 255, 0.12);
  --about-title-color: #E8E6E3;
  --about-body-color: rgba(232, 230, 227, 0.86);
  --about-muted-color: #9AA5B1;
  --about-mono: 'JetBrains Mono', 'SFMono-Regular', Consolas, monospace;
  --about-serif: 'Noto Serif SC', Georgia, serif;
  --about-sans: 'Noto Sans SC', system-ui, sans-serif;
}

.page-about__hero {
  position: relative;
  padding-top: 40px;
  padding-bottom: 56px;
  overflow: hidden;
}

.page-about__hero::before {
  content: "ABOUT";
  position: absolute;
  right: -24px;
  top: 48px;
  font-family: var(--about-mono);
  font-size: 96px;
  font-weight: 800;
  letter-spacing: -0.04em;
  color: transparent;
  -webkit-text-stroke: 1px rgba(212, 175, 55, 0.18);
  pointer-events: none;
  z-index: 0;
}

.page-about__rail {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 28px;
  font-family: var(--about-sans);
  font-size: 13px;
  color: var(--about-muted-color);
  position: relative;
  z-index: 1;
}

.page-about__rail-num {
  font-family: var(--about-mono);
  font-size: 30px;
  font-weight: 800;
  line-height: 1;
  color: var(--about-gold);
}

.page-about__rail-label {
  font-family: var(--about-sans);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--about-muted-color);
  text-transform: uppercase;
  white-space: nowrap;
}

.page-about__rail-text {
  font-family: var(--about-sans);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.12em;
  color: var(--about-gold);
  text-transform: uppercase;
  white-space: nowrap;
}

.page-about__rail-line {
  flex: 0 0 48px;
  height: 1px;
  background: linear-gradient(90deg, rgba(212, 175, 55, 0.6), transparent);
}

.page-about__hero-inner,
.page-about__section-body {
  max-width: 800px;
}

.page-about__breadcrumbs {
  margin-bottom: 24px;
}

.page-about__title {
  font-family: var(--about-serif);
  font-size: 31px;
  font-weight: 800;
  line-height: 1.32;
  color: var(--about-title-color);
  margin: 0 0 16px;
  letter-spacing: -0.01em;
}

.page-about__title-line {
  display: block;
  color: var(--about-gold);
}

.page-about__lead {
  font-family: var(--about-sans);
  font-size: 16px;
  line-height: 1.85;
  color: var(--about-muted-color);
  margin: 0 0 32px;
  max-width: 56em;
}

.page-about__hero-media {
  margin: 0;
  position: relative;
  z-index: 1;
}

.page-about__hero-media img,
.page-about__data-visual img,
.page-about__version-visual img {
  max-width: 100%;
  height: auto;
  display: block;
}

.page-about__section {
  padding-top: 56px;
  padding-bottom: 56px;
  border-top: 1px solid var(--about-line);
  position: relative;
}

.page-about__section--alt {
  background: linear-gradient(135deg, rgba(59, 43, 92, 0.1), rgba(10, 22, 40, 0) 58%);
  border-top-color: rgba(212, 175, 55, 0.22);
}

.page-about__section--service {
  background: linear-gradient(135deg, rgba(107, 29, 42, 0.16), rgba(10, 22, 40, 0) 60%);
}

.page-about__section-kicker {
  font-family: var(--about-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--about-blue);
  margin: 0 0 10px;
}

.page-about__section-title {
  position: relative;
  font-family: var(--about-serif);
  font-size: 26px;
  font-weight: 800;
  line-height: 1.35;
  color: var(--about-title-color);
  margin: 0 0 20px;
  padding-left: 18px;
}

.page-about__section-title::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.16em;
  bottom: 0.16em;
  width: 3px;
  background: linear-gradient(180deg, var(--about-gold), transparent);
}

.page-about__prose p {
  font-family: var(--about-sans);
  font-size: 15px;
  line-height: 1.9;
  color: var(--about-body-color);
  margin: 0 0 16px;
}

.page-about__prose-footer {
  font-family: var(--about-serif);
  font-size: 17px;
  font-weight: 700;
  color: var(--about-gold);
  border-left: 3px solid var(--about-gold);
  padding-left: 16px;
  margin: 24px 0;
}

.page-about__more-link {
  margin-top: 8px;
}

.page-about__pillars {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin: 28px 0;
}

.page-about__pillar {
  border: 1px solid var(--about-line);
  border-left: 3px solid var(--about-gold);
  padding: 20px 22px;
  background: rgba(255, 255, 255, 0.02);
  transition: border-color 0.25s ease, background-color 0.25s ease;
}

.page-about__pillar:hover {
  border-color: var(--about-gold);
  background: var(--about-gold-soft);
}

.page-about__pillar-index {
  display: inline-block;
  font-family: var(--about-mono);
  font-size: 12px;
  font-weight: 700;
  color: var(--about-blue);
  margin-bottom: 8px;
  letter-spacing: 0.1em;
}

.page-about__pillar h3 {
  font-family: var(--about-serif);
  font-size: 16px;
  font-weight: 700;
  color: var(--about-title-color);
  margin: 0 0 10px;
}

.page-about__pillar p {
  font-family: var(--about-sans);
  font-size: 14px;
  line-height: 1.85;
  color: var(--about-body-color);
  margin: 0;
}

.page-about__data-cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin: 28px 0;
}

.page-about__data-card {
  border: 1px solid var(--about-line);
  background: linear-gradient(135deg, rgba(20, 43, 60, 0.55), rgba(10, 22, 40, 0.55));
  padding: 22px;
  transition: transform 0.25s ease, border-color 0.25s ease;
}

.page-about__data-card:hover {
  transform: translateY(-4px);
  border-color: rgba(0, 212, 255, 0.5);
}

.page-about__data-layer {
  display: inline-block;
  font-family: var(--about-mono);
  font-size: 12px;
  font-weight: 700;
  color: var(--about-blue);
  letter-spacing: 0.12em;
  padding: 2px 12px 2px 0;
  border-right: 2px solid var(--about-blue);
  margin-right: 8px;
  background: var(--about-blue-soft);
  margin-bottom: 12px;
}

.page-about__data-card h3 {
  font-family: var(--about-serif);
  font-size: 17px;
  font-weight: 700;
  color: var(--about-title-color);
  margin: 0 0 10px;
}

.page-about__data-card p {
  font-family: var(--about-sans);
  font-size: 14px;
  line-height: 1.8;
  color: var(--about-body-color);
  margin: 0;
}

.page-about__data-visual,
.page-about__version-visual {
  margin: 28px 0 0;
}

.page-about__timeline {
  position: relative;
  padding-left: 32px;
  margin: 32px 0;
}

.page-about__timeline::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 4px;
  bottom: 4px;
  width: 1px;
  background: linear-gradient(to bottom, var(--about-gold), var(--about-blue));
  opacity: 0.5;
}

.page-about__version-card {
  position: relative;
  margin-bottom: 18px;
}

.page-about__version-card::before {
  content: "";
  position: absolute;
  left: -24px;
  top: 24px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--about-gold);
  border: 1px solid #0A1628;
  z-index: 2;
}

.page-about__version-card--current::before {
  background: var(--about-blue);
  box-shadow: 0 0 12px rgba(0, 212, 255, 0.6);
}

.page-about__version-toggle {
  display: flex;
  width: 100%;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  background: transparent;
  border: 1px solid var(--about-line);
  border-radius: 0;
  padding: 18px 20px;
  color: var(--about-title-color);
  font-family: var(--about-sans);
  text-align: left;
  cursor: pointer;
  transition: border-color 0.25s ease, background-color 0.25s ease;
}

.page-about__version-toggle:hover {
  border-color: var(--about-gold);
  background: var(--about-gold-soft);
}

.page-about__version-badge {
  font-family: var(--about-mono);
  font-size: 14px;
  font-weight: 700;
  background: var(--about-gold-soft);
  color: var(--about-gold);
  padding: 4px 10px;
  border-right: 2px solid var(--about-gold);
  flex: 0 0 auto;
}

.page-about__version-card--current .page-about__version-badge {
  background: var(--about-blue-soft);
  color: var(--about-blue);
  border-right-color: var(--about-blue);
}

.page-about__version-name {
  font-family: var(--about-serif);
  font-size: 16px;
  font-weight: 700;
  flex: 0 1 auto;
  min-width: 0;
}

.page-about__version-summary {
  font-size: 13px;
  color: var(--about-muted-color);
  flex: 1 1 auto;
  text-align: right;
  padding-right: 8px;
}

.page-about__version-icon {
  font-family: var(--about-mono);
  font-size: 18px;
  color: var(--about-gold);
  transition: transform 0.25s ease;
  flex: 0 0 auto;
}

.page-about__version-card--current .page-about__version-icon {
  color: var(--about-blue);
}

.page-about__version-toggle[aria-expanded="true"] .page-about__version-icon {
  transform: rotate(45deg);
}

.page-about__version-detail {
  padding: 12px 20px 4px;
  font-family: var(--about-sans);
  font-size: 14px;
  line-height: 1.85;
  color: var(--about-body-color);
}

.page-about__version-detail p {
  margin: 0 0 12px;
}

.page-about__service-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin: 28px 0;
}

.page-about__service-item {
  border: 1px solid var(--about-line);
  padding: 20px 22px;
  background: rgba(255, 255, 255, 0.02);
}

.page-about__service-item h3 {
  font-family: var(--about-serif);
  font-size: 17px;
  font-weight: 700;
  color: var(--about-gold);
  margin: 0 0 10px;
}

.page-about__service-item p {
  font-family: var(--about-sans);
  font-size: 14px;
  line-height: 1.85;
  color: var(--about-body-color);
  margin: 0 0 8px;
}

.page-about__service-note {
  font-size: 13px;
  color: var(--about-muted-color);
}

.page-about__link {
  color: var(--about-blue);
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color 0.25s ease;
}

.page-about__link:hover {
  color: var(--about-gold);
}

.page-about__service-promise {
  border-top: 1px solid var(--about-line);
  padding-top: 20px;
  margin-top: 24px;
  font-family: var(--about-serif);
  font-size: 16px;
  font-weight: 700;
  color: var(--about-title-color);
}

.page-about__next {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  padding-top: 32px;
  padding-bottom: 56px;
  border-top: 1px solid var(--about-line);
}

.page-about__next-label {
  font-family: var(--about-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--about-muted-color);
  margin-right: 8px;
  flex: 0 0 auto;
}

.page-about__next-link {
  display: inline-block;
  font-size: 14px;
  font-weight: 600;
  padding: 10px 20px;
  border: 1px solid var(--about-line);
  color: var(--about-title-color);
  text-decoration: none;
  transition: all 0.25s ease;
}

.page-about__next-link:hover {
  border-color: var(--about-gold);
  color: var(--about-gold);
  background: var(--about-gold-soft);
}

@media (min-width: 992px) {
  .page-about__hero {
    display: grid;
    grid-template-columns: 260px minmax(0, 1fr);
    column-gap: 72px;
    padding-top: 64px;
    padding-bottom: 80px;
  }

  .page-about__rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    margin-bottom: 0;
    padding-top: 8px;
  }

  .page-about__rail-num {
    font-size: 46px;
  }

  .page-about__rail-line {
    width: 1px;
    height: 160px;
    flex: none;
    background: linear-gradient(180deg, rgba(212, 175, 55, 0.7), rgba(0, 212, 255, 0.2));
    margin-top: 16px;
  }

  .page-about__section {
    display: grid;
    grid-template-columns: 260px minmax(0, 1fr);
    column-gap: 72px;
    padding-top: 72px;
    padding-bottom: 72px;
  }

  .page-about__section-body {
    max-width: 820px;
  }

  .page-about__title {
    font-size: 44px;
    line-height: 1.22;
  }

  .page-about__lead {
    font-size: 18px;
  }

  .page-about__section-title {
    font-size: 30px;
  }

  .page-about__pillars {
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
  }

  .page-about__data-cards {
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
  }

  .page-about__service-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
  }

  .page-about__next {
    padding-top: 40px;
    padding-bottom: 72px;
  }
}

@media (min-width: 768px) and (max-width: 991px) {
  .page-about__data-cards,
  .page-about__pillars {
    grid-template-columns: repeat(3, 1fr);
    gap: 18px;
  }
}