.page-about {
  --about-rail-w: 148px;
  --about-line: rgba(0, 229, 255, 0.24);
  background: var(--ink-800);
  color: var(--mist);
  font-family: var(--font-body);
  overflow-x: hidden;
}

.page-about .breadcrumb {
  padding: 18px 0 0;
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--cyan-soft);
}

.page-about .breadcrumb a {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .breadcrumb a:hover {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .breadcrumb__sep {
  margin: 0 8px;
  color: var(--steel);
}

/* ---------- hero ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(26px, 4vw, 48px) 0 clamp(38px, 6vw, 72px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    repeating-linear-gradient(90deg, rgba(0, 229, 255, 0.06) 0 1px, transparent 1px 80px),
    repeating-linear-gradient(0deg, rgba(0, 229, 255, 0.045) 0 1px, transparent 1px 80px);
  -webkit-mask-image: linear-gradient(180deg, #000 0%, transparent 88%);
  mask-image: linear-gradient(180deg, #000 0%, transparent 88%);
  pointer-events: none;
}

.page-about .about-hero__grid {
  position: relative;
  display: grid;
  gap: 30px;
  align-items: start;
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-size: clamp(34px, 6.4vw, 68px);
  line-height: 0.98;
  letter-spacing: 0.01em;
  color: var(--mist);
  transform: skewX(-5deg);
  transform-origin: left center;
  padding-right: 6px;
}

.page-about .about-hero__text {
  max-width: 34em;
  margin: 18px 0 0;
  font-size: var(--fs-body);
  line-height: 1.9;
  color: rgba(230, 237, 245, 0.82);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .about-hero__panel {
  border: var(--line-cyan);
  border-left: 3px solid var(--orange);
  border-radius: var(--radius);
  background: rgba(6, 18, 36, 0.62);
  padding: 20px 20px 8px;
  backdrop-filter: blur(6px);
}

.page-about .about-panel__title {
  margin: 0 0 14px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--cyan-soft);
}

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

.page-about .about-stat {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 0;
  border-top: 1px solid rgba(27, 58, 92, 0.9);
  transition: border-color var(--dur) var(--ease);
}

.page-about .about-stat:hover {
  border-top-color: var(--cyan);
}

.page-about .about-stat dt {
  font-size: 13px;
  letter-spacing: 0.04em;
  color: rgba(230, 237, 245, 0.72);
}

.page-about .about-stat dd {
  margin: 0;
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.page-about .about-stat__num {
  font-family: var(--font-data);
  font-size: clamp(24px, 4vw, 34px);
  line-height: 1;
  color: var(--cyan);
}

.page-about .about-stat__unit {
  font-size: 12px;
  color: var(--amber);
}

/* ---------- chapter nav ---------- */
.page-about .chapter-nav {
  position: relative;
  border-top: var(--line-cyan);
  border-bottom: var(--line-cyan);
  background: rgba(6, 18, 36, 0.72);
}

.page-about .chapter-nav__inner {
  display: flex;
  gap: 9px;
  overflow-x: auto;
  padding: 13px 0;
  scrollbar-width: none;
}

.page-about .chapter-nav__inner::-webkit-scrollbar {
  display: none;
}

.page-about .chapter-nav a {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 7px 14px;
  border: 1px solid rgba(124, 240, 255, 0.24);
  border-radius: 999px;
  font-size: 13px;
  color: var(--mist);
  text-decoration: none;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.page-about .chapter-nav a:hover,
.page-about .chapter-nav a:focus-visible {
  color: var(--cyan);
  border-color: var(--cyan);
  transform: translateY(-2px);
}

.page-about .chapter-nav__idx {
  font-family: var(--font-data);
  font-size: 11px;
  color: var(--orange);
}

/* ---------- chapter shell ---------- */
.page-about .chapter {
  position: relative;
  padding: clamp(46px, 8vw, 96px) 0;
}

.page-about .chapter__grid {
  display: grid;
  gap: 22px;
}

.page-about .chapter__rail {
  display: flex;
  align-items: baseline;
  gap: 14px;
}

.page-about .chapter__num {
  font-family: var(--font-display);
  font-size: clamp(40px, 8vw, 64px);
  line-height: 0.85;
  color: transparent;
  -webkit-text-stroke: 1.5px var(--cyan);
  letter-spacing: 0.02em;
}

.page-about .chapter__label {
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--cyan-soft);
  white-space: nowrap;
}

.page-about .chapter__title {
  margin: 0 0 18px;
  font-family: var(--font-display);
  font-size: clamp(26px, 4.4vw, 44px);
  line-height: 1.06;
  letter-spacing: 0.01em;
  color: var(--mist);
}

.page-about .chapter__body p,
.page-about .chapter__lead {
  max-width: 34em;
  margin: 0 0 14px;
  font-size: var(--fs-body);
  line-height: 1.9;
  color: rgba(230, 237, 245, 0.82);
}

.page-about .about-subtitle {
  margin: 34px 0 10px;
  font-family: var(--font-body);
  font-weight: 700;
  font-size: clamp(18px, 2.2vw, 22px);
  color: var(--cyan-soft);
}

/* paper chapters */
.page-about .chapter--paper {
  background: var(--paper);
  color: var(--ink-800);
  background-image:
    repeating-linear-gradient(90deg, rgba(11, 31, 58, 0.06) 0 1px, transparent 1px 64px),
    repeating-linear-gradient(0deg, rgba(11, 31, 58, 0.05) 0 1px, transparent 1px 64px);
}

.page-about .chapter--paper .chapter__title {
  color: var(--ink-800);
}

.page-about .chapter--paper .chapter__num {
  -webkit-text-stroke-color: var(--orange);
}

.page-about .chapter--paper .chapter__label {
  color: var(--ink-700);
}

.page-about .chapter--paper .chapter__body p,
.page-about .chapter--paper .chapter__lead {
  color: rgba(11, 31, 58, 0.82);
}

.page-about .chapter--dark {
  background: var(--ink-900);
}

/* ---------- split + figures ---------- */
.page-about .about-split {
  display: grid;
  gap: 26px;
  align-items: start;
}

.page-about .about-figure {
  margin: 0;
  border: 1px solid rgba(0, 229, 255, 0.28);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--ink-900);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(0.9) contrast(1.05);
}

.page-about .about-figure figcaption {
  padding: 10px 14px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.06em;
  line-height: 1.6;
  color: var(--cyan-soft);
  border-top: 1px solid rgba(0, 229, 255, 0.18);
  background: rgba(6, 18, 36, 0.85);
}

.page-about .about-figure--wide img {
  aspect-ratio: 2 / 1;
}

.page-about .about-figure--band img {
  aspect-ratio: 4 / 3;
}

/* ---------- flow ---------- */
.page-about .about-flow {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .flow-step {
  position: relative;
  padding: 16px 18px 16px 22px;
  border-left: 3px solid var(--ink-700);
  background: rgba(255, 255, 255, 0.55);
  border-radius: 0 var(--radius) var(--radius) 0;
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.page-about .flow-step:hover {
  border-left-color: var(--orange);
  transform: translateX(3px);
}

.page-about .flow-step__idx {
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--orange);
}

.page-about .flow-step__name {
  margin: 6px 0 6px;
  font-size: 18px;
  font-weight: 700;
  color: var(--ink-800);
}

.page-about .flow-step__desc {
  margin: 0;
  max-width: 34em;
  font-size: 15px;
  line-height: 1.85;
  color: rgba(11, 31, 58, 0.78);
}

/* ---------- tags ---------- */
.page-about .about-tags {
  list-style: none;
  margin: 18px 0 20px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 10px;
}

.page-about .about-tag {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 12px 14px;
  border: 1px solid rgba(11, 31, 58, 0.22);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.62);
  transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .about-tag:hover {
  border-color: var(--orange);
  background: #fff;
}

.page-about .about-tag__name {
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 15px;
  color: var(--ink-800);
}

.page-about .about-tag__desc {
  font-size: 13px;
  line-height: 1.6;
  color: rgba(11, 31, 58, 0.7);
}

/* ---------- timeline ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: 28px 0 0;
  padding: 0 0 0 20px;
  border-left: 1px dashed rgba(0, 229, 255, 0.35);
}

.page-about .tl-node {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 0 0 28px 6px;
}

.page-about .tl-node::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 8px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--ink-900);
  border: 2px solid var(--steel);
  transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .tl-node:hover::before,
.page-about .tl-node:focus-within::before {
  border-color: var(--cyan);
  background: var(--orange);
}

.page-about .tl-node__year {
  align-self: flex-start;
  font-family: var(--font-data);
  font-size: 20px;
  letter-spacing: 0.08em;
  color: var(--cyan);
  border: 1px solid rgba(0, 229, 255, 0.4);
  border-radius: 999px;
  padding: 3px 14px;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .tl-node:hover .tl-node__year,
.page-about .tl-node:focus-within .tl-node__year {
  border-color: var(--orange);
  color: var(--amber);
}

.page-about .tl-node__title {
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  font-size: clamp(18px, 2.4vw, 23px);
  font-weight: 700;
  color: var(--mist);
}

.page-about .tl-node__kw {
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: rgba(255, 200, 87, 0.62);
  border-left: 2px solid rgba(255, 107, 53, 0.5);
  padding-left: 8px;
  transition: color var(--dur) var(--ease);
}

.page-about .tl-node:hover .tl-node__kw {
  color: var(--amber);
}

.page-about .tl-node__desc {
  margin: 0;
  max-width: 34em;
  font-size: 15px;
  line-height: 1.85;
  color: rgba(230, 237, 245, 0.76);
}

/* ---------- partners ---------- */
.page-about .about-partners {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 22px 0 20px;
}

.page-about .partner-metric {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 14px 16px;
  border-left: 3px solid var(--orange);
  background: rgba(255, 255, 255, 0.55);
}

.page-about .partner-metric__num {
  font-family: var(--font-data);
  font-size: clamp(34px, 7vw, 58px);
  line-height: 1;
  color: var(--ink-800);
}

.page-about .partner-metric__label {
  font-size: 13px;
  letter-spacing: 0.04em;
  color: rgba(11, 31, 58, 0.72);
}

.page-about .about-linklist {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  border-top: 1px solid rgba(11, 31, 58, 0.2);
}

.page-about .about-linklist li {
  border-bottom: 1px solid rgba(11, 31, 58, 0.16);
}

.page-about .about-linklist a {
  display: block;
  padding: 13px 2px;
  font-size: 15px;
  color: var(--ink-800);
  text-decoration: none;
  transition: color var(--dur) var(--ease), padding-left var(--dur) var(--ease);
}

.page-about .about-linklist a:hover,
.page-about .about-linklist a:focus-visible {
  color: var(--orange);
  padding-left: 8px;
}

/* ---------- rhythm ---------- */
.page-about .about-rhythm {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .rhythm-item {
  padding: 18px 18px 16px;
  border: var(--line-soft);
  border-radius: var(--radius);
  background: rgba(6, 18, 36, 0.55);
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.page-about .rhythm-item:hover {
  border-color: var(--cyan);
  transform: translateY(-2px);
}

.page-about .rhythm-item__tag {
  display: inline-block;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--ink-900);
  background: var(--amber);
  border-radius: 3px;
  padding: 3px 9px;
}

.page-about .rhythm-item__name {
  margin: 10px 0 6px;
  font-size: 17px;
  font-weight: 700;
  color: var(--mist);
}

.page-about .rhythm-item p {
  margin: 0;
  max-width: 34em;
  font-size: 15px;
  line-height: 1.85;
  color: rgba(230, 237, 245, 0.78);
}

/* ---------- closing cta ---------- */
.page-about .about-cta {
  position: relative;
  background: var(--orange);
  color: var(--ink-900);
  padding: clamp(40px, 7vw, 76px) 0;
  clip-path: polygon(0 4%, 100% 0, 100% 100%, 0 96%);
}

.page-about .about-cta__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: clamp(26px, 5vw, 48px);
  line-height: 1.05;
  letter-spacing: 0.01em;
  color: var(--ink-900);
}

.page-about .about-cta__text {
  margin: 0 0 22px;
  max-width: 32em;
  font-size: var(--fs-body);
  line-height: 1.8;
  color: rgba(6, 18, 36, 0.82);
}

.page-about .about-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-cta .btn--ghost {
  color: var(--ink-900);
  border-color: rgba(6, 18, 36, 0.55);
}

.page-about .about-cta .btn--ghost:hover {
  border-color: var(--ink-900);
  background: rgba(6, 18, 36, 0.08);
}

/* ---------- focus ---------- */
.page-about a:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}

/* ---------- responsive ---------- */
@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 0.85fr);
    gap: 52px;
  }

  .page-about .chapter__grid {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: 48px;
  }

  .page-about .chapter__rail {
    flex-direction: column;
    align-items: flex-start;
    align-self: start;
    position: sticky;
    top: calc(var(--deck-h) + 22px);
    gap: 8px;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.85fr);
    gap: 34px;
  }

  .page-about .about-flow {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
  }

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

  .page-about .about-partners {
    grid-template-columns: repeat(2, minmax(0, 220px));
  }

  .page-about .about-timeline {
    padding-left: 26px;
  }

  .page-about .tl-node {
    display: grid;
    grid-template-columns: 118px minmax(0, 1fr);
    gap: 20px;
    align-items: start;
  }

  .page-about .tl-node::before {
    left: -32px;
    top: 14px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .flow-step:hover,
  .page-about .rhythm-item:hover,
  .page-about .chapter-nav a:hover,
  .page-about .about-linklist a:hover {
    transform: none;
    padding-left: 2px;
  }

  .page-about .about-hero__title {
    transform: none;
  }
}