.page-about {
  --about-deep: #0A1D3A;
  --about-signal: #F5F7FA;
  --about-orange: #FF4F1A;
  --about-lime: #A3FF12;
  --about-ink: #121212;
  --about-line: #D0D7E2;
  --about-blue: #264D7E;
  background: var(--about-signal);
}

.page-about .breadcrumbs {
  max-width: var(--container);
  margin: 24px auto 0;
  padding: 0 20px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--about-blue);
}

.page-about .breadcrumbs a {
  color: var(--about-blue);
  text-decoration: none;
  transition: color 0.2s ease;
}

.page-about .breadcrumbs a:hover {
  color: var(--about-orange);
}

.page-about .breadcrumbs-sep {
  margin: 0 8px;
  color: var(--about-line);
}

.page-about .breadcrumbs [aria-current="page"] {
  color: var(--about-ink);
  font-weight: 700;
}

.page-about .about-hero {
  background: var(--about-deep);
  clip-path: polygon(0 0, 100% 0, 100% 90%, 0 100%);
  padding: 72px 0 96px;
  margin-top: 24px;
}

.page-about .about-hero-inner {
  display: grid;
  gap: 32px;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 20px;
}

.page-about .about-hero-index {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--about-lime);
  border: 1px solid rgba(163, 255, 18, 0.5);
  padding: 5px 12px;
  margin-bottom: 18px;
}

.page-about .about-hero h1 {
  margin: 0 0 16px;
  color: #FFFFFF;
  font-family: var(--font-heading);
  font-size: clamp(28px, 5vw, 50px);
  line-height: 1.15;
  max-width: 720px;
}

.page-about .about-hero-desc {
  margin: 0 0 12px;
  color: rgba(245, 247, 250, 0.88);
  font-size: 17px;
  line-height: 1.7;
  max-width: 660px;
}

.page-about .about-hero-sub {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--about-orange);
}

.page-about .about-hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}

.page-about .about-stat {
  background: rgba(38, 77, 126, 0.4);
  border: 1px solid rgba(163, 255, 18, 0.45);
  padding: 18px 10px;
  text-align: center;
}

.page-about .about-stat-num {
  display: block;
  font-family: var(--font-heading);
  font-size: 38px;
  line-height: 1;
  color: var(--about-orange);
}

.page-about .about-stat-label {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  color: rgba(245, 247, 250, 0.82);
}

.page-about .about-layout {
  display: grid;
  gap: 40px;
  max-width: var(--container);
  margin: 0 auto;
  padding: 48px 20px 80px;
}

.page-about .about-toc {
  border: 2px solid var(--about-ink);
  background: #FFFFFF;
  padding: 20px;
  align-self: start;
}

.page-about .about-toc-title {
  margin: 0 0 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--about-line);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--about-blue);
}

.page-about .about-toc-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-toc-list a {
  display: block;
  padding: 10px 8px;
  border-left: 3px solid transparent;
  color: var(--about-ink);
  text-decoration: none;
  font-weight: 700;
  font-size: 15px;
  transition: border-color 0.2s ease, color 0.2s ease, background 0.2s ease;
}

.page-about .about-toc-list a:hover,
.page-about .about-toc-list a:focus {
  border-left-color: var(--about-orange);
  color: var(--about-orange);
  background: rgba(255, 79, 26, 0.06);
}

.page-about .about-toc-note {
  margin-top: 16px;
  padding-top: 12px;
  border-top: 1px dashed var(--about-line);
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--about-blue);
}

.page-about .about-main {
  position: relative;
  min-width: 0;
}

.page-about .about-timeline-media {
  margin-bottom: 48px;
  border: 2px solid var(--about-ink);
  box-shadow: 8px 8px 0 var(--about-deep);
}

.page-about .about-main .media-frame img {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .about-main figcaption {
  padding: 10px 14px;
  border-top: 1px solid var(--about-line);
  background: var(--about-signal);
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--about-blue);
}

.page-about .about-stage {
  position: relative;
  background: #FFFFFF;
  border: 2px solid var(--about-ink);
  box-shadow: 6px 6px 0 rgba(10, 29, 58, 0.12);
  padding: 24px 20px;
  margin-bottom: 48px;
  scroll-margin-top: 100px;
}

.page-about .about-stage::before {
  content: "";
  position: absolute;
  top: -2px;
  left: -2px;
  width: 56px;
  height: 8px;
  background: var(--about-orange);
}

.page-about .about-stage:target {
  animation: about-flash 1s ease-out;
}

@keyframes about-flash {
  0% {
    box-shadow: 0 0 0 4px var(--about-lime), 6px 6px 0 rgba(10, 29, 58, 0.12);
  }
  100% {
    box-shadow: 6px 6px 0 rgba(10, 29, 58, 0.12);
  }
}

.page-about .about-stage-head {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  margin-bottom: 16px;
}

.page-about .about-stage-idx {
  flex-shrink: 0;
  min-width: 56px;
  font-family: var(--font-mono);
  font-size: 40px;
  line-height: 1;
  color: var(--about-orange);
}

.page-about .about-stage h2 {
  margin: 0;
  padding-top: 4px;
  font-family: var(--font-heading);
  font-size: clamp(20px, 3vw, 28px);
  line-height: 1.2;
}

.page-about .about-stage-body p {
  margin: 0 0 14px;
  color: #333333;
  font-size: 16px;
}

.page-about .about-stage-body > p:last-of-type {
  margin-bottom: 0;
}

.page-about .about-detail {
  margin-top: 18px;
  border: 1px solid var(--about-line);
  background: var(--about-signal);
}

.page-about .about-detail summary {
  position: relative;
  cursor: pointer;
  list-style: none;
  padding: 14px 44px 14px 16px;
  font-weight: 700;
  color: var(--about-deep);
  font-size: 14px;
}

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

.page-about .about-detail summary::after {
  content: "+";
  position: absolute;
  right: 16px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 22px;
  line-height: 1;
  color: var(--about-orange);
}

.page-about .about-detail[open] summary::after {
  content: "–";
}

.page-about .about-detail-list {
  margin: 0;
  padding: 0 16px 14px 34px;
}

.page-about .about-detail-list li {
  margin: 6px 0;
  font-size: 14px;
  color: #444444;
}

.page-about .about-fix-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin: 20px 0;
}

.page-about .about-fix-card {
  background: var(--about-deep);
  border: 2px solid var(--about-orange);
  text-align: center;
  padding: 14px 6px;
}

.page-about .about-fix-num {
  display: block;
  font-family: var(--font-heading);
  font-size: 32px;
  line-height: 1.05;
  color: var(--about-orange);
}

.page-about .about-fix-label {
  display: block;
  margin-top: 5px;
  font-size: 12px;
  line-height: 1.4;
  color: rgba(245, 247, 250, 0.82);
}

.page-about .about-fix-media {
  margin: 24px 0 0;
  border: 2px solid var(--about-ink);
  background: var(--about-signal);
}

.page-about .about-data-strip {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  background: var(--about-deep);
  padding: 20px;
  margin: 24px 0;
}

.page-about .about-data-item {
  text-align: center;
  border-left: 2px solid var(--about-lime);
  padding: 8px 4px;
}

.page-about .about-data-value {
  display: block;
  font-family: var(--font-heading);
  font-size: 36px;
  line-height: 1;
  color: var(--about-lime);
}

.page-about .about-data-name {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: rgba(245, 247, 250, 0.76);
}

.page-about .about-data-media {
  margin: 24px 0 0;
  border: 2px solid var(--about-ink);
  background: var(--about-signal);
}

.page-about .about-cert-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin-top: 24px;
}

.page-about .about-cert-item {
  border: 2px solid var(--about-blue);
  background: var(--about-signal);
  color: var(--about-deep);
  text-align: center;
  padding: 14px 8px;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
}

.page-about .about-trust-note {
  display: flex;
  gap: 18px;
  align-items: flex-start;
  background: var(--about-deep);
  border: 2px solid var(--about-ink);
  box-shadow: 8px 8px 0 rgba(255, 79, 26, 0.6);
  padding: 24px 20px;
  margin-bottom: 32px;
}

.page-about .about-trust-mark {
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border: 2px solid var(--about-orange);
  color: var(--about-orange);
  font-family: var(--font-heading);
  font-size: 26px;
  font-weight: 700;
}

.page-about .about-trust-copy p {
  margin: 0 0 8px;
  color: rgba(245, 247, 250, 0.92);
  font-size: 15px;
  line-height: 1.7;
}

.page-about .about-trust-copy .about-trust-sub {
  margin-bottom: 0;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--about-lime);
}

.page-about .about-bottom-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  padding: 8px 0 32px;
}

.page-about .about-bottom-nav .button {
  text-decoration: none;
  font-weight: 700;
}

@media (min-width: 600px) {
  .page-about .about-hero-inner {
    grid-template-columns: 1.15fr 0.85fr;
    align-items: center;
  }

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

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

  .page-about .about-stage {
    padding: 32px 28px;
  }

  .page-about .about-stage-idx {
    font-size: 54px;
    min-width: 68px;
  }
}

@media (min-width: 900px) {
  .page-about .about-layout {
    grid-template-columns: 220px 1fr;
    gap: 56px;
    padding-top: 64px;
  }

  .page-about .about-toc {
    position: sticky;
    top: 100px;
  }

  .page-about .about-main {
    padding-left: 36px;
  }

  .page-about .about-main::before {
    content: "";
    position: absolute;
    left: 0;
    top: 40px;
    bottom: 40px;
    width: 2px;
    background: linear-gradient(to bottom, var(--about-lime) 0%, var(--about-lime) 68%, var(--about-orange) 100%);
  }

  .page-about .about-hero {
    padding-top: 96px;
    padding-bottom: 120px;
    clip-path: polygon(0 0, 100% 0, 100% 86%, 0 100%);
  }
}