.page-about {
  --about-band-h: 56px;
  --about-rail-w: 2fr;
  --about-body-w: 10fr;
  --about-gap: clamp(1.25rem, 3vw, 2.75rem);
  --about-pad-y: clamp(2.25rem, 6vw, 4.25rem);
  background: var(--ink-void);
  color: var(--silver);
  font-family: var(--font-sans);
  padding-bottom: clamp(3rem, 9vw, 6.5rem);
  overflow-x: hidden;
}

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

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

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

.page-about .breadcrumb {
  padding-top: clamp(1rem, 3vw, 1.75rem);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--silver-dim);
}

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

.page-about .breadcrumb li + li::before {
  content: "/";
  margin-right: 0.5rem;
  color: var(--line);
}

/* ---------- hero ---------- */

.page-about .about-hero {
  position: relative;
  padding: var(--about-pad-y) 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, var(--line-soft) 1px, transparent 1px),
    linear-gradient(to bottom, var(--line-soft) 1px, transparent 1px);
  background-size: 72px 72px;
  opacity: 0.32;
  -webkit-mask-image: radial-gradient(ellipse at 70% 20%, #000 0%, transparent 72%);
  mask-image: radial-gradient(ellipse at 70% 20%, #000 0%, transparent 72%);
  pointer-events: none;
}

.page-about .about-hero__inner {
  position: relative;
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
}

.page-about .about-hero__lead {
  max-width: 62ch;
}

.page-about .eyebrow {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--silver-dim);
  margin: 0 0 1rem;
}

.page-about .about-hero h1 {
  font-size: clamp(2rem, 7vw, 3.75rem);
  line-height: 1.12;
  font-weight: 900;
  color: var(--white);
  letter-spacing: -0.01em;
  margin: 0 0 1.25rem;
}

.page-about .about-hero__text {
  font-size: clamp(1rem, 2.2vw, 1.0625rem);
  line-height: 1.85;
  color: var(--silver);
  max-width: 40ch;
  margin: 0 0 1.5rem;
}

.page-about .about-hero__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--silver-dim);
  margin: 0;
}

.page-about .rule-dot {
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--orange);
  display: inline-block;
}

.page-about .about-hero__panel {
  border: 1px solid var(--line);
  border-left: 3px solid var(--cyan);
  background: linear-gradient(160deg, rgba(18, 34, 77, 0.72), rgba(11, 21, 51, 0.6));
  padding: clamp(1.25rem, 3vw, 1.75rem);
}

.page-about .status-list {
  margin: 0 0 1rem;
  padding: 0;
}

.page-about .status-list__row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1rem;
  padding: 0.55rem 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .status-list__row dt {
  font-size: 0.8125rem;
  color: var(--silver-dim);
}

.page-about .status-list__row dd {
  margin: 0;
  font-size: 0.9375rem;
  color: var(--silver);
  white-space: nowrap;
}

.page-about .status-list__row:last-child {
  border-bottom: 0;
}

.page-about .about-hero__panel-note {
  margin: 0.75rem 0 0;
  font-size: 0.8125rem;
  line-height: 1.7;
  color: var(--silver-dim);
}

/* ---------- figure ---------- */

.page-about .about-figure {
  margin: 0;
  position: relative;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: clamp(200px, 38vw, 420px);
  object-fit: cover;
  filter: saturate(0.72) brightness(0.82);
}

.page-about .about-figure figcaption {
  position: absolute;
  left: var(--shell-pad);
  bottom: clamp(0.75rem, 2vw, 1.25rem);
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.14em;
  color: var(--silver-dim);
  background: rgba(5, 10, 26, 0.72);
  padding: 0.35rem 0.6rem;
  border-left: 2px solid var(--orange);
}

/* ---------- band ---------- */

.page-about .band {
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
  background: var(--ink-deep);
  scroll-margin-top: 6rem;
}

.page-about .band--paper {
  background: var(--paper);
  color: var(--paper-ink);
  border-color: rgba(36, 31, 22, 0.2);
}

.page-about .band-inner {
  display: flex;
  align-items: center;
  gap: clamp(0.75rem, 2vw, 1.5rem);
  min-height: var(--about-band-h);
  padding-top: 0.75rem;
  padding-bottom: 0.75rem;
}

.page-about .band__index {
  font-size: 0.8125rem;
  color: var(--orange);
  letter-spacing: 0.1em;
}

.page-about .band--paper .band__index {
  color: #B4520F;
}

.page-about .band__label {
  font-size: clamp(1rem, 2.6vw, 1.25rem);
  font-weight: 700;
  color: var(--silver);
  letter-spacing: 0.02em;
}

.page-about .band--paper .band__label {
  color: var(--paper-ink);
}

.page-about .band-inner__rail {
  margin-left: auto;
  font-size: 0.6875rem;
  letter-spacing: 0.24em;
  color: var(--line);
  display: none;
}

.page-about .band--paper .band-inner__rail {
  color: rgba(36, 31, 22, 0.35);
}

/* ---------- grid ---------- */

.page-about .about-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
  padding-top: clamp(2rem, 5vw, 3.5rem);
  padding-bottom: clamp(2rem, 5vw, 3.5rem);
}

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

.page-about .v-note {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.24em;
  color: var(--silver-dim);
  writing-mode: vertical-rl;
  text-orientation: mixed;
  border-left: 1px solid var(--line);
  padding-left: 0.75rem;
}

.page-about .about-lede {
  font-size: clamp(1.0625rem, 2.6vw, 1.1875rem);
  line-height: 1.8;
  color: var(--white);
  margin: 0 0 2rem;
  padding-left: 1rem;
  border-left: 2px solid var(--cyan);
  max-width: 42ch;
}

.page-about .about-body > p {
  line-height: 1.85;
  max-width: 40ch;
}

.page-about .about-foot-note {
  font-size: 0.875rem;
  line-height: 1.8;
  color: var(--silver-dim);
  margin-top: 1.25rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line-soft);
  max-width: 44ch;
}

.page-about .sub-head {
  font-size: clamp(1.125rem, 3vw, 1.375rem);
  color: var(--white);
  font-weight: 700;
  margin: 2.5rem 0 1rem;
}

/* ---------- reasons ---------- */

.page-about .reason-list {
  list-style: none;
  margin: 0 0 2.25rem;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.page-about .reason {
  background: var(--ink-void);
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1rem;
  padding: clamp(1.1rem, 3vw, 1.6rem);
  transition: background var(--ease);
}

.page-about .reason:hover {
  background: var(--ink-deep);
}

.page-about .reason__idx {
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  color: var(--orange);
  padding-top: 0.35rem;
}

.page-about .reason__title {
  font-size: clamp(1.0625rem, 2.6vw, 1.25rem);
  font-weight: 700;
  color: var(--white);
  margin: 0 0 0.6rem;
}

.page-about .reason__body p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.85;
  color: var(--silver);
  max-width: 42ch;
}

/* ---------- code strip ---------- */

.page-about .code-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.page-about .field {
  position: relative;
  display: inline-flex;
}

.page-about .code-chip {
  border: 1px solid var(--line);
  padding: 0.5rem 0.75rem;
  font-size: 0.8125rem;
  letter-spacing: 0.1em;
  color: var(--cyan);
  background: var(--ink-mid);
  cursor: help;
  transition: border-color var(--ease), background var(--ease);
}

.page-about .code-chip:hover,
.page-about .code-chip:focus-within {
  border-color: var(--cyan);
  background: #16305f;
}

.page-about .field__tip {
  position: absolute;
  left: 0;
  bottom: calc(100% + 8px);
  z-index: 5;
  width: min(280px, 74vw);
  background: var(--paper);
  color: var(--paper-ink);
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  line-height: 1.65;
  letter-spacing: 0;
  padding: 0.7rem 0.85rem;
  opacity: 0;
  visibility: hidden;
  transform: translateY(4px);
  transition: opacity var(--ease), transform var(--ease), visibility var(--ease);
}

.page-about .field:hover .field__tip,
.page-about .field:focus-within .field__tip {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

/* ---------- timeline ---------- */

.page-about .timeline-wrap {
  display: grid;
  gap: var(--about-gap);
}

.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 1.5rem;
  border-left: 1px solid var(--line);
}

.page-about .timeline__item {
  position: relative;
  padding-bottom: 2.5rem;
}

.page-about .timeline__item:last-child {
  padding-bottom: 0;
}

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: calc(-1.5rem - 5px);
  top: 0.4rem;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink-void);
  border: 1px solid var(--line);
  transition: background var(--ease), border-color var(--ease), box-shadow var(--ease);
}

.page-about .timeline__item:hover::before {
  background: var(--cyan);
  border-color: var(--cyan);
  box-shadow: 0 0 0 4px rgba(95, 227, 208, 0.16);
}

.page-about .timeline__phase {
  font-size: 0.6875rem;
  letter-spacing: 0.2em;
  color: var(--silver-dim);
  margin-bottom: 0.6rem;
}

.page-about .timeline__item:hover .timeline__phase {
  color: var(--cyan);
}

.page-about .timeline__title {
  font-size: clamp(1.0625rem, 2.6vw, 1.25rem);
  font-weight: 700;
  color: var(--white);
  margin: 0 0 0.5rem;
}

.page-about .timeline__item p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.85;
  color: var(--silver);
  max-width: 42ch;
}

.page-about .timeline-visual {
  margin: 0;
  border: 1px solid var(--line);
  padding: 0.5rem;
  background: var(--ink-deep);
}

.page-about .timeline-visual img {
  display: block;
  width: 100%;
  height: clamp(180px, 46vw, 420px);
  object-fit: cover;
  filter: saturate(0.7) brightness(0.78);
}

.page-about .timeline-visual figcaption {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.1em;
  color: var(--silver-dim);
  padding: 0.6rem 0.25rem 0.15rem;
}

/* ---------- process / paper ---------- */

.page-about .paper-panel {
  background: var(--paper);
  color: var(--paper-ink);
  padding: clamp(1.25rem, 4vw, 2.25rem);
  margin-bottom: 2.25rem;
  position: relative;
}

.page-about .paper-panel::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  background: var(--orange);
}

.page-about .flow-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1.75rem;
}

.page-about .flow-step {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px dashed rgba(36, 31, 22, 0.25);
}

.page-about .flow-step:last-child {
  padding-bottom: 0;
  border-bottom: 0;
}

.page-about .flow-step__time {
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  color: #B4520F;
}

.page-about .flow-step__body h3 {
  font-size: clamp(1rem, 2.5vw, 1.125rem);
  font-weight: 700;
  margin: 0.35rem 0 0.5rem;
  color: var(--paper-ink);
  line-height: 1.45;
}

.page-about .flow-step__body p {
  margin: 0 0 0.75rem;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: #3A3325;
  max-width: 42ch;
}

.page-about .paper-panel .disclosure {
  border-top: 1px solid rgba(36, 31, 22, 0.18);
  padding-top: 0.5rem;
}

.page-about .paper-panel .disclosure summary {
  cursor: pointer;
  font-size: 0.8125rem;
  font-family: var(--font-mono);
  letter-spacing: 0.06em;
  color: #6B5A38;
  padding: 0.35rem 0;
  transition: color var(--ease);
}

.page-about .paper-panel .disclosure summary:hover {
  color: #B4520F;
}

.page-about .paper-panel .disclosure__body {
  padding-top: 0.5rem;
}

.page-about .plain-list {
  margin: 0;
  padding-left: 1.1rem;
  list-style: square;
}

.page-about .plain-list li {
  font-size: 0.875rem;
  line-height: 1.75;
  color: #3A3325;
}

.page-about .split-metrics {
  display: grid;
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
  margin: 0;
}

.page-about .split-metric {
  background: var(--ink-void);
  padding: 1.15rem 1.25rem;
}

.page-about .split-metric dt {
  font-size: 0.9375rem;
  color: var(--white);
  font-weight: 700;
}

.page-about .split-metric dd {
  margin: 0.35rem 0 0.5rem;
  font-size: 1.5rem;
  color: var(--orange);
}

.page-about .split-metric p {
  margin: 0;
  font-size: 0.875rem;
  line-height: 1.75;
  color: var(--silver-dim);
}

/* ---------- archive ---------- */

.page-about .archive-split {
  display: grid;
  gap: var(--about-gap);
}

.page-about .archive-text p {
  line-height: 1.85;
  max-width: 40ch;
}

.page-about .archive-visual {
  margin: 0;
  border-left: 3px solid var(--cyan);
}

.page-about .archive-visual img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(0.68) brightness(0.82);
}

.page-about .archive-visual figcaption {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.1em;
  color: var(--silver-dim);
  padding: 0.6rem 0.25rem 0;
}

.page-about .tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line-soft);
}

.page-about .tag {
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--silver-dim);
  border: 1px solid var(--line);
  padding: 0.4rem 0.7rem;
  transition: border-color var(--ease), color var(--ease);
}

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

.page-about .tag--cyan {
  color: var(--cyan);
  border-color: rgba(95, 227, 208, 0.45);
}

/* ---------- revision ---------- */

.page-about .revision-list {
  list-style: none;
  margin: 0 0 2.75rem;
  padding: 0;
  display: grid;
  gap: 1.25rem;
}

.page-about .revision {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1rem;
  padding-left: 0.25rem;
  border-left: 1px solid var(--line);
  padding-bottom: 0.25rem;
}

.page-about .revision__idx {
  font-size: 0.8125rem;
  color: var(--orange);
  padding-left: 0.85rem;
  padding-top: 0.15rem;
}

.page-about .revision h3 {
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--white);
  margin: 0 0 0.4rem;
}

.page-about .revision p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--silver);
  max-width: 42ch;
}

.page-about .next-links {
  border-top: 1px solid var(--line-soft);
  padding-top: 1.75rem;
}

.page-about .link-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-soft);
}

.page-about .link-list li {
  background: var(--ink-void);
}

.page-about .link-list a {
  display: block;
  padding: 0.95rem 1rem;
  font-size: 0.9375rem;
  color: var(--silver);
  border-bottom: 0;
  transition: background var(--ease), color var(--ease);
}

.page-about .link-list a:hover,
.page-about .link-list a:focus-visible {
  background: var(--ink-mid);
  color: var(--cyan);
}

/* ---------- watermark ---------- */

.page-about .about-watermark {
  margin: clamp(3rem, 8vw, 5rem) 0 0;
  padding: 0 var(--shell-pad);
  font-size: clamp(4.5rem, 22vw, 14rem);
  line-height: 0.85;
  letter-spacing: -0.03em;
  color: transparent;
  -webkit-text-stroke: 1px var(--line);
  opacity: 0.5;
  pointer-events: none;
  user-select: none;
  text-align: right;
}

/* ---------- responsive ---------- */

@media (min-width: 720px) {
  .page-about .band-inner__rail {
    display: inline;
  }

  .page-about .flow-step {
    grid-template-columns: 6.5rem 1fr;
    gap: 1.25rem;
  }

  .page-about .flow-step__time {
    padding-top: 0.3rem;
  }

  .page-about .split-metrics {
    grid-template-columns: repeat(3, 1fr);
  }

  .page-about .archive-split {
    grid-template-columns: 7fr 5fr;
    align-items: start;
  }
}

@media (min-width: 900px) {
  .page-about {
    --about-rail-w: 2fr;
  }

  .page-about .about-hero__inner {
    grid-template-columns: 7fr 5fr;
    align-items: start;
  }

  .page-about .about-grid {
    grid-template-columns: minmax(64px, 2fr) minmax(0, 10fr);
    column-gap: clamp(1.5rem, 4vw, 3.5rem);
  }

  .page-about .about-rail {
    display: flex;
    justify-content: flex-start;
  }

  .page-about .timeline-wrap {
    grid-template-columns: minmax(0, 8fr) minmax(180px, 4fr);
    column-gap: clamp(1.5rem, 3vw, 2.5rem);
    align-items: start;
  }

  .page-about .timeline-visual {
    position: sticky;
    top: 7rem;
  }

  .page-about .timeline-visual img {
    height: clamp(320px, 40vw, 480px);
  }
}