.page-about {
  --about-radius: 2px;
  --about-gap: clamp(1rem, 3vw, 2rem);
  overflow-x: hidden;
  background:
    radial-gradient(900px 520px at 88% -6%, rgba(53, 230, 224, 0.12), transparent 62%),
    radial-gradient(700px 420px at 4% 30%, rgba(255, 107, 74, 0.07), transparent 60%),
    linear-gradient(165deg, var(--ink-900) 0%, var(--ink-800) 58%, var(--ink-900) 100%);
  color: var(--white);
  padding-bottom: clamp(2rem, 6vw, 4rem);
}

.page-about .breadcrumb {
  padding-top: clamp(1.25rem, 4vw, 2rem);
}

.page-about a {
  color: var(--cyan);
  text-decoration: none;
}

.page-about a:hover,
.page-about a:focus-visible {
  color: var(--coral);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---------- hero ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(1.25rem, 3vw, 2rem) 0 clamp(1.75rem, 4vw, 2.5rem);
}

.page-about .about-hero__frame {
  position: relative;
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(1.5rem, 4vw, 2.75rem);
  padding: clamp(1.25rem, 4vw, 2.75rem);
  border: 2px solid var(--line);
  background: rgba(10, 34, 56, 0.6);
  box-shadow: var(--shadow-hard);
}

.page-about .about-hero__frame::before,
.page-about .about-hero__frame::after {
  content: "";
  position: absolute;
  width: 22px;
  height: 22px;
  border: 2px solid var(--cyan);
  pointer-events: none;
}

.page-about .about-hero__frame::before {
  top: -6px;
  left: -6px;
  border-right: 0;
  border-bottom: 0;
}

.page-about .about-hero__frame::after {
  right: -6px;
  bottom: -6px;
  border-left: 0;
  border-top: 0;
}

.page-about .about-hero__kicker {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin: 0 0 1rem;
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  color: var(--cyan);
}

.page-about .about-hero__kicker::before {
  content: "";
  width: 34px;
  height: 2px;
  background: var(--coral);
}

.page-about .about-hero h1 {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2.5rem, 8vw, 4.6rem);
  line-height: 1.02;
  letter-spacing: -0.01em;
  color: var(--white);
}

.page-about .about-hero__text {
  max-width: 46ch;
  margin: 0 0 1.5rem;
  font-size: clamp(0.95rem, 1.6vw, 1.06rem);
  line-height: 1.8;
  color: var(--mute);
}

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

.page-about .about-hero__figure {
  margin: 0;
}

.page-about .about-hero__figure .media-frame {
  border: 2px solid var(--line);
  background: var(--ink-700);
  box-shadow: 6px 6px 0 rgba(6, 21, 34, 0.6);
}

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

.page-about .about-hero__figure .media-frame__caption {
  margin-top: 0.6rem;
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--mute);
}

/* ---------- stats ---------- */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(1.25rem, 3vw, 2rem) 0 0;
  padding: 0;
  list-style: none;
  background: var(--line);
  border: 2px solid var(--line);
}

.page-about .about-stats__item {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  padding: 1rem 1.1rem;
  background: rgba(6, 21, 34, 0.85);
}

.page-about .about-stats__num {
  font-size: clamp(1.7rem, 4vw, 2.4rem);
  font-weight: 600;
  line-height: 1;
  color: var(--cyan);
}

.page-about .about-stats__unit {
  font-size: 0.85rem;
  color: var(--mute);
  margin-left: 0.15rem;
}

.page-about .about-stats__label {
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  color: var(--mute);
}

/* ---------- index ---------- */
.page-about .about-index {
  position: relative;
  padding: 0 0 clamp(1.5rem, 4vw, 2.5rem);
}

.page-about .about-index__list {
  display: flex;
  gap: 0.5rem;
  margin: 0;
  padding: 0 0 0.5rem;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
  border-bottom: 2px solid var(--line);
}

.page-about .about-index__link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  white-space: nowrap;
  padding: 0.55rem 0.85rem;
  border: 2px solid var(--line);
  background: rgba(10, 34, 56, 0.5);
  font-size: 0.82rem;
  color: var(--white);
  transition: border-color var(--dur) ease, background-color var(--dur) ease, color var(--dur) ease;
}

.page-about .about-index__link .mono {
  color: var(--coral);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  border-color: var(--cyan);
  background: rgba(53, 230, 224, 0.1);
  color: var(--white);
  text-decoration: none;
}

/* ---------- sections ---------- */
.page-about .about-section {
  position: relative;
  padding: clamp(2rem, 5vw, 3.5rem) 0;
  border-top: 2px solid var(--line);
}

.page-about .about-section--alt {
  background: linear-gradient(180deg, rgba(10, 34, 56, 0.55), rgba(6, 21, 34, 0.2));
}

.page-about .about-section__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(1rem, 3vw, 2.25rem);
}

.page-about .about-section__rail {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  padding-left: 0.85rem;
  border-left: 4px solid var(--cyan);
}

.page-about .about-section__num {
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  font-weight: 600;
  line-height: 1;
  color: var(--cyan);
}

.page-about .about-section__label {
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  color: var(--mute);
}

.page-about .about-section__title {
  margin: 0 0 0.9rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.55rem, 4vw, 2.3rem);
  line-height: 1.15;
  color: var(--white);
}

.page-about .about-section__intro {
  margin: 0 0 1.5rem;
  font-size: 0.98rem;
  line-height: 1.8;
  color: var(--mute);
  max-width: 62ch;
}

.page-about .about-section__body p {
  margin: 0 0 1rem;
  font-size: 0.95rem;
  line-height: 1.85;
  color: var(--mute);
  max-width: 66ch;
}

.page-about .about-section__foot {
  margin-top: 1.5rem;
  padding-top: 0.9rem;
  border-top: 1px dashed var(--line);
  font-size: 0.85rem;
  color: var(--mute);
}

/* ---------- quote ---------- */
.page-about .about-quote {
  margin: 1.5rem 0 0;
  padding: 1.1rem 1.25rem;
  border: 2px solid var(--line);
  border-left: 6px solid var(--coral);
  background: rgba(6, 21, 34, 0.7);
}

.page-about .about-quote__text {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  font-size: clamp(1.1rem, 2.6vw, 1.4rem);
  font-weight: 700;
  line-height: 1.4;
  color: var(--white);
  max-width: none;
}

.page-about .about-quote__source {
  margin: 0;
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--mute);
}

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

.page-about .about-panel {
  padding: 1.15rem 1.25rem;
  border: 2px solid var(--line);
  background: rgba(10, 34, 56, 0.55);
  transition: border-color var(--dur) ease, transform var(--dur) ease, box-shadow var(--dur) ease;
}

.page-about .about-panel:hover {
  border-color: var(--cyan);
  box-shadow: 5px 5px 0 rgba(53, 230, 224, 0.14);
}

.page-about .about-panel__tag {
  margin: 0 0 0.55rem;
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  color: var(--coral);
}

.page-about .about-panel h3 {
  margin: 0 0 0.6rem;
  font-family: var(--font-display);
  font-size: 1.28rem;
  font-weight: 700;
  color: var(--white);
  letter-spacing: 0.01em;
}

.page-about .about-panel p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.8;
  color: var(--mute);
  max-width: none;
}

/* ---------- certification ---------- */
.page-about .about-cert {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
  align-items: start;
}

.page-about .about-cert__figure .media-frame {
  border: 2px solid var(--line);
  background:
    repeating-linear-gradient(135deg, rgba(53, 230, 224, 0.06) 0 2px, transparent 2px 12px),
    var(--ink-700);
}

.page-about .about-cert__figure img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: contain;
}

.page-about .about-cert__caption {
  margin: 0.6rem 0 0;
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--cyan);
  text-align: center;
}

.page-about .about-cert__item {
  border: 2px solid var(--line);
  border-bottom-width: 0;
  background: rgba(6, 21, 34, 0.62);
  transition: border-color var(--dur) ease;
}

.page-about .about-cert__list .about-cert__item:last-child {
  border-bottom-width: 2px;
}

.page-about .about-cert__item:hover,
.page-about .about-cert__item[open] {
  border-color: rgba(53, 230, 224, 0.55);
}

.page-about .about-cert__item summary {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  padding: 0.9rem 1rem;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--white);
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-cert__item summary::after {
  content: "＋";
  margin-left: auto;
  font-family: var(--font-mono);
  color: var(--cyan);
}

.page-about .about-cert__item[open] summary::after {
  content: "－";
  color: var(--coral);
}

.page-about .about-cert__no {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  flex: 0 0 26px;
  border: 2px solid var(--cyan);
  font-size: 0.75rem;
  color: var(--cyan);
}

.page-about .about-cert__item p {
  margin: 0;
  padding: 0 1rem 1rem 3.1rem;
  font-size: 0.88rem;
  line-height: 1.8;
  color: var(--mute);
  max-width: none;
}

/* ---------- timeline ---------- */
.page-about .about-section--timeline {
  background: linear-gradient(180deg, rgba(13, 43, 69, 0.65), rgba(6, 21, 34, 0.3));
}

.page-about .about-tl__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
}

.page-about .about-tl__head .about-section__title {
  margin: 0;
  flex: 1 1 240px;
}

.page-about .about-tl__hint {
  margin: 0;
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--mute);
}

.page-about .about-tl {
  overflow-x: auto;
  padding: 0 max(1rem, calc((100vw - var(--shell)) / 2)) 1rem;
  scrollbar-width: thin;
}

.page-about .about-tl:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 4px;
}

.page-about .about-tl__list {
  display: flex;
  gap: 1rem;
  margin: 0;
  padding: 1.4rem 0 0;
  list-style: none;
  border-top: 2px solid var(--line);
  min-width: max-content;
}

.page-about .about-tl__item {
  position: relative;
  width: min(78vw, 280px);
  flex: 0 0 auto;
  padding: 1.1rem 1.15rem;
  border: 2px solid var(--line);
  background: rgba(10, 34, 56, 0.7);
  transition: border-color var(--dur) ease, background-color var(--dur) ease;
}

.page-about .about-tl__item::before {
  content: "";
  position: absolute;
  top: -2rem;
  left: 1.15rem;
  width: 10px;
  height: 10px;
  background: var(--cyan);
  border: 2px solid var(--ink-900);
  transform: rotate(45deg);
}

.page-about .about-tl__item:hover {
  border-color: var(--coral);
  background: rgba(16, 48, 74, 0.8);
}

.page-about .about-tl__year {
  display: block;
  margin-bottom: 0.5rem;
  font-size: 1.45rem;
  font-weight: 600;
  color: var(--coral);
  letter-spacing: 0.02em;
}

.page-about .about-tl__item h3 {
  margin: 0 0 0.55rem;
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--white);
}

.page-about .about-tl__item p {
  margin: 0;
  font-size: 0.86rem;
  line-height: 1.75;
  color: var(--mute);
}

/* ---------- network ---------- */
.page-about .about-net {
  margin: 1.5rem 0 1.25rem;
}

.page-about .about-net .media-frame {
  border: 2px solid var(--line);
  background: var(--ink-700);
}

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

.page-about .about-net .media-frame__caption {
  margin-top: 0.55rem;
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--mute);
}

.page-about .about-net__nodes {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-net__node {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.45rem 0.75rem;
  border: 2px solid var(--line);
  background: rgba(6, 21, 34, 0.7);
  font-size: 0.8rem;
  color: var(--white);
  transition: border-color var(--dur) ease, color var(--dur) ease, background-color var(--dur) ease;
}

.page-about .about-net__node .mono {
  color: var(--cyan);
  font-size: 0.8rem;
}

.page-about .about-net__node:hover {
  border-color: var(--cyan);
  background: rgba(53, 230, 224, 0.12);
  color: var(--cyan);
}

/* ---------- next plan ---------- */
.page-about .about-section--next {
  background: linear-gradient(200deg, rgba(6, 21, 34, 0.4), rgba(13, 43, 69, 0.7));
}

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

.page-about .about-plan__item {
  position: relative;
  padding: 1.15rem 1.25rem 1.15rem 1.4rem;
  border: 2px solid var(--line);
  background: rgba(6, 21, 34, 0.55);
}

.page-about .about-plan__item::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  background: var(--mint);
}

.page-about .about-plan__item h3 {
  margin: 0 0 0.55rem;
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--white);
}

.page-about .about-plan__item p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.8;
  color: var(--mute);
  max-width: none;
}

/* ---------- cta ---------- */
.page-about .about-cta {
  margin-top: clamp(1.5rem, 4vw, 2.5rem);
  border-top: 2px solid var(--line);
  border-bottom: 2px solid var(--line);
  background:
    repeating-linear-gradient(115deg, rgba(255, 107, 74, 0.09) 0 3px, transparent 3px 14px),
    linear-gradient(120deg, rgba(255, 107, 74, 0.16), rgba(53, 230, 224, 0.1));
}

.page-about .about-cta__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
  padding: clamp(1.5rem, 4vw, 2.5rem) 0;
}

.page-about .about-cta h2 {
  margin: 0 0 0.6rem;
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 4vw, 2.1rem);
  font-weight: 700;
  line-height: 1.2;
  color: var(--white);
}

.page-about .about-cta__text p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--mute);
  max-width: 56ch;
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-content: start;
}

/* ---------- responsive ---------- */
@media (min-width: 720px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-panels {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-panel--wide {
    grid-column: span 2;
  }

  .page-about .about-cert {
    grid-template-columns: minmax(0, 0.72fr) minmax(0, 1.28fr);
  }

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

  .page-about .about-cta__inner {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
    align-items: center;
  }
}

@media (min-width: 1024px) {
  .page-about .about-hero__frame {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 0.85fr);
    align-items: start;
  }

  .page-about .about-section__grid {
    grid-template-columns: 200px minmax(0, 1fr);
    gap: clamp(1.5rem, 4vw, 3rem);
  }

  .page-about .about-section__rail {
    position: sticky;
    top: calc(var(--header-h) + 1.5rem);
    flex-direction: column;
    align-items: flex-start;
    gap: 0.6rem;
    align-self: start;
    padding-left: 1rem;
  }

  .page-about .about-section__label {
    writing-mode: vertical-rl;
    letter-spacing: 0.22em;
    font-size: 0.74rem;
  }

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

  .page-about .about-panel {
    grid-column: span 3;
  }

  .page-about .about-panel--wide {
    grid-column: span 4;
  }

  .page-about .about-panel:not(.about-panel--wide) {
    grid-column: span 2;
  }

  .page-about .about-tl__item {
    width: 320px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-panel,
  .page-about .about-index__link,
  .page-about .about-tl__item,
  .page-about .about-net__node,
  .page-about .about-cert__item {
    transition: none;
  }
}