.page-about {
  --about-blue-soft: rgba(10, 42, 74, 0.97);
  --about-blue-line: rgba(255, 255, 255, 0.1);
  --about-ink-soft: rgba(237, 232, 220, 0.92);
  --about-ink-dim: rgba(237, 232, 220, 0.72);
  --about-sec-num-size: 52px;
  --about-rail-w: 180px;
  position: relative;
  background-color: var(--color-bg);
}

.page-about .about-hero {
  padding: 36px 20px 44px;
  border-bottom: 1px solid var(--color-line);
  background-image: linear-gradient(to right, rgba(26, 29, 29, 0.035) 1px, transparent 1px);
  background-size: 32px 32px;
}

.page-about .about-hero-layout {
  display: grid;
  gap: 28px;
  max-width: 1200px;
  margin: 0 auto;
}

.page-about .about-kicker {
  margin: 0 0 10px;
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--color-gray);
}

.page-about .about-hero-main h1 {
  margin: 0 0 18px;
  font-family: var(--font-heading);
  font-size: clamp(26px, 4.5vw, 48px);
  line-height: 1.16;
  max-width: 15em;
}

.page-about .about-hero-desc {
  margin: 0 0 24px;
  max-width: 36em;
  font-size: 15px;
  line-height: 1.75;
  color: var(--color-gray);
}

.page-about .about-hero-main .btn {
  margin-top: 8px;
}

.page-about .about-toc {
  border-left: 2px solid var(--color-green);
  padding: 4px 0 4px 18px;
}

.page-about .about-toc-title {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--color-gray);
}

.page-about .about-toc ol {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.page-about .about-toc a {
  font-family: var(--font-data);
  font-size: 13px;
  color: var(--color-ink);
  text-decoration: none;
  transition: color 0.2s ease, padding-left 0.2s ease;
}

.page-about .about-toc a:hover {
  color: var(--color-blue);
  padding-left: 4px;
}

.page-about .about-archive {
  padding: 0;
}

.page-about .about-archive-rail {
  display: none;
}

.page-about .about-archive-rule {
  display: none;
}

.page-about .about-docs {
  position: relative;
  padding: 48px 20px 0;
  background-image: linear-gradient(to right, rgba(26, 29, 29, 0.03) 1px, transparent 1px);
  background-size: 36px 36px;
}

.page-about .about-section {
  margin-bottom: 72px;
}

.page-about .about-section-head {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 14px;
  align-items: baseline;
  padding-bottom: 14px;
  border-bottom: 2px solid var(--color-blue);
  margin-bottom: 28px;
}

.page-about .about-sec-num {
  font-family: var(--font-heading);
  font-size: var(--about-sec-num-size);
  font-weight: 700;
  line-height: 0.9;
  color: var(--color-gold);
}

.page-about .about-section .section-title {
  margin: 0 0 6px;
  font-size: clamp(20px, 3vw, 30px);
  line-height: 1.2;
}

.page-about .about-section .section-meta {
  margin: 0;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--color-gray);
}

.page-about .about-section-body p {
  font-size: 14px;
  line-height: 1.75;
  color: var(--color-gray);
  max-width: 64em;
}

.page-about .about-section-body p + p {
  margin-top: 14px;
}

.page-about .link-arrow {
  display: inline-block;
  margin-top: 20px;
  font-family: var(--font-data);
  font-size: 13px;
  color: var(--color-blue);
  text-decoration: none;
  border-bottom: 1px solid var(--color-blue);
  transition: color 0.2s ease, border-color 0.2s ease;
}

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

.page-about .about-timeline {
  position: relative;
  display: grid;
  gap: 36px;
  margin: 8px 0 0;
  padding-left: 26px;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 6px;
  bottom: 8px;
  width: 2px;
  background: var(--color-line);
}

.page-about .about-version-item {
  position: relative;
}

.page-about .about-version-item::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 4px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--color-bg);
  border: 3px solid var(--color-blue);
  transition: transform 0.25s ease, background 0.25s ease, border-color 0.25s ease;
  z-index: 1;
}

.page-about .about-version-item:hover::before {
  transform: scale(1.4);
  background: var(--color-green);
  border-color: var(--color-green);
}

.page-about .about-version-current::before {
  border-color: var(--color-green);
  background: var(--color-green);
  box-shadow: 0 0 0 4px rgba(0, 230, 118, 0.22);
}

.page-about .about-version-current:hover::before {
  box-shadow: 0 0 0 8px rgba(0, 230, 118, 0.16);
}

.page-about .version-node {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin-bottom: 10px;
}

.page-about .version-node-year {
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--color-gray);
}

.page-about .version-node-code {
  font-family: var(--font-data);
  font-size: 20px;
  font-weight: 700;
  color: var(--color-blue);
}

.page-about .about-version-current .version-node-code {
  color: var(--color-gold);
}

.page-about .version-title {
  margin: 0 0 8px;
  font-family: var(--font-heading);
  font-size: 19px;
  line-height: 1.3;
}

.page-about .about-version-item p {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-gray);
  max-width: 58em;
}

.page-about .about-version-figure {
  margin: 40px 0 0;
}

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

.page-about .about-team-grid {
  display: grid;
  gap: 28px;
  margin-top: 32px;
  padding: 30px 24px;
  background-color: var(--about-blue-soft);
  background-image: linear-gradient(var(--about-blue-line) 1px, transparent 1px), linear-gradient(90deg, var(--about-blue-line) 1px, transparent 1px);
  background-size: 24px 24px;
  border-left: 4px solid var(--color-green);
  border-radius: var(--radius);
}

.page-about .about-team-intro p {
  margin: 0 0 22px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--about-ink-soft);
}

.page-about .about-role-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .about-role-list li {
  display: grid;
  grid-template-columns: 1fr;
  gap: 4px;
  padding-bottom: 12px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
}

.page-about .role-label {
  font-family: var(--font-data);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--color-gold);
}

.page-about .role-desc {
  font-size: 13px;
  line-height: 1.65;
  color: var(--about-ink-soft);
  opacity: 0.88;
}

.page-about .about-team-figure {
  margin: 0;
  padding: 6px;
  background: rgba(245, 240, 230, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.18);
  transition: border-color 0.25s ease, background 0.25s ease;
}

.page-about .about-team-figure:hover {
  border-color: var(--color-gold);
  background: rgba(255, 179, 0, 0.08);
}

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

.page-about .about-team-figure figcaption {
  padding-top: 8px;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--about-ink-dim);
}

.page-about .about-cert-layout {
  display: grid;
  gap: 28px;
  margin-top: 32px;
}

.page-about .about-cert-list {
  display: grid;
  gap: 0;
}

.page-about .about-cert-item {
  display: grid;
  grid-template-columns: minmax(84px, auto) 1fr;
  gap: 14px;
  align-items: start;
  padding: 18px 0;
  border-bottom: 1px solid var(--color-line);
}

.page-about .about-cert-item .tag {
  min-width: 84px;
  text-align: center;
}

.page-about .about-cert-item p {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-gray);
  max-width: 46em;
}

.page-about .about-cert-link {
  display: inline-block;
  margin-top: 20px;
  font-family: var(--font-data);
  font-size: 13px;
  color: var(--color-blue);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.25s ease, color 0.25s ease;
}

.page-about .about-cert-link:hover {
  color: var(--color-gold);
  border-bottom-color: var(--color-gold);
}

.page-about .about-cert-figure {
  margin: 0;
}

.page-about .about-stats-band {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: rgba(255, 255, 255, 0.14);
  border-top: 1px solid rgba(255, 255, 255, 0.14);
}

.page-about .about-stat {
  display: grid;
  gap: 4px;
  padding: 24px 12px;
  text-align: center;
  background-color: var(--color-dark);
}

.page-about .about-stat-num {
  font-family: var(--font-data);
  font-size: 28px;
  font-weight: 700;
  line-height: 1;
  color: var(--color-green);
}

.page-about .about-stat-suffix {
  font-size: 14px;
  color: var(--color-gold);
}

.page-about .about-stat-label {
  font-size: 11px;
  letter-spacing: 0.06em;
  color: rgba(237, 232, 220, 0.78);
}

.page-about .about-outro {
  padding: 48px 20px 56px;
  border-top: 1px solid var(--color-gold);
  text-align: center;
}

.page-about .about-outro-kicker {
  margin: 0 0 16px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--color-gray);
}

.page-about .about-outro-claim {
  margin: 0 auto 28px;
  max-width: 24em;
  font-family: var(--font-heading);
  font-size: clamp(17px, 2.6vw, 24px);
  line-height: 1.55;
}

.page-about .about-outro-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
}

@media (min-width: 640px) {
  .page-about .about-role-list li {
    grid-template-columns: 88px 1fr;
    gap: 12px;
  }

  .page-about .about-stats-band {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 1024px) {
  .page-about .about-hero {
    padding: 52px 48px 60px;
  }

  .page-about .about-hero-layout {
    grid-template-columns: minmax(0, 1fr) 240px;
    align-items: start;
  }

  .page-about .about-toc {
    display: none;
  }

  .page-about .about-archive {
    display: grid;
    grid-template-columns: var(--about-rail-w, 180px) 1px minmax(0, 1fr);
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 48px;
  }

  .page-about .about-archive-rail {
    display: flex;
    flex-direction: column;
    position: sticky;
    top: calc(var(--header-h) + 20px);
    align-self: start;
    padding: 12px 0 0 20px;
    border-left: 2px solid var(--color-line);
  }

  .page-about .about-rail-title {
    display: block;
    font-family: var(--font-data);
    font-size: 10px;
    letter-spacing: 0.2em;
    color: var(--color-gray);
    margin-bottom: 18px;
    padding-left: 4px;
  }

  .page-about .about-rail-item {
    position: relative;
    display: grid;
    grid-template-columns: 28px 1fr auto;
    align-items: baseline;
    gap: 8px;
    padding: 12px 0 12px 8px;
    text-decoration: none;
    border-bottom: 1px solid rgba(208, 208, 208, 0.55);
    transition: background 0.2s ease;
  }

  .page-about .about-rail-item:last-child {
    border-bottom-color: var(--color-line);
  }

  .page-about .about-rail-dot {
    position: absolute;
    left: -27px;
    top: 50%;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--color-bg);
    border: 2px solid var(--color-blue);
    transform: translateY(-50%);
    transition: transform 0.25s ease, background 0.25s ease, border-color 0.25s ease;
  }

  .page-about .about-rail-item:hover .about-rail-dot {
    transform: translateY(-50%) scale(1.45);
    background: var(--color-green);
    border-color: var(--color-green);
  }

  .page-about .about-rail-num {
    font-family: var(--font-data);
    font-size: 12px;
    font-weight: 700;
    color: var(--color-gold);
  }

  .page-about .about-rail-name {
    font-family: var(--font-data);
    font-size: 12px;
    color: var(--color-ink);
    letter-spacing: 0.05em;
  }

  .page-about .about-rail-year {
    font-family: var(--font-data);
    font-size: 10px;
    color: var(--color-gray);
  }

  .page-about .about-archive-rule {
    display: block;
    background: var(--color-line);
  }

  .page-about .about-docs {
    padding: 56px 0 0 56px;
  }

  .page-about .about-section {
    margin-bottom: 96px;
  }

  .page-about .about-sec-num {
    --about-sec-num-size: 72px;
    font-size: var(--about-sec-num-size);
  }

  .page-about .about-section-body p,
  .page-about .about-version-item p {
    font-size: 15px;
  }

  .page-about .about-team-grid {
    grid-template-columns: minmax(0, 1fr) minmax(280px, 420px);
    align-items: center;
    padding: 40px 36px;
  }

  .page-about .about-cert-layout {
    grid-template-columns: minmax(0, 1fr) 320px;
    align-items: start;
  }

  .page-about .about-stats-band {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

  .page-about .about-stat {
    padding: 32px 16px;
  }

  .page-about .about-stat-num {
    font-size: 32px;
  }

  .page-about .about-outro {
    padding: 64px 48px;
  }
}