.page-about {
  --about-rail: 168px;
  --about-line: rgba(79, 107, 87, 0.42);
  --about-glass: rgba(221, 235, 224, 0.08);
  display: block;
  background:
    radial-gradient(1100px 560px at 84% -8%, rgba(183, 255, 60, 0.07), transparent 62%),
    radial-gradient(900px 520px at 6% 34%, rgba(184, 107, 75, 0.06), transparent 60%),
    var(--c-ink);
  color: var(--c-chalk);
  font-family: var(--font-body);
  overflow-x: hidden;
}

.page-about *,
.page-about *::before,
.page-about *::after {
  box-sizing: border-box;
}

.page-about a:focus-visible,
.page-about button:focus-visible,
.page-about summary:focus-visible {
  outline: 2px solid var(--c-lime);
  outline-offset: 3px;
  border-radius: 4px;
}

.page-about h1,
.page-about h2,
.page-about h3 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.12;
  color: var(--c-chalk);
}

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

.page-about .about-hero {
  position: relative;
  padding: clamp(18px, 3vw, 30px) 0 clamp(36px, 6vw, 78px);
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(183, 255, 60, 0.5), transparent);
}

.page-about .hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(20px, 3vw, 40px);
  margin-top: clamp(20px, 4vw, 44px);
}

.page-about .hero-index {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .index-list {
  list-style: none;
  margin: 10px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 4px 14px;
}

.page-about .index-list a {
  display: flex;
  align-items: baseline;
  gap: 9px;
  padding: 6px 0;
  font-size: 14px;
  color: var(--text-soft);
  text-decoration: none;
  border-bottom: 1px dashed transparent;
  transition: color 0.18s ease, border-color 0.18s ease;
}

.page-about .index-list a:hover {
  color: var(--c-lime);
  border-bottom-color: rgba(183, 255, 60, 0.45);
}

.page-about .index-list .data {
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--c-mineral);
}

.page-about .hero-main h1 {
  font-size: clamp(2.1rem, 6.4vw, 4.4rem);
  max-width: 17ch;
}

.page-about .hero-lead {
  margin: 20px 0 0;
  max-width: 52ch;
  font-size: clamp(15px, 1.8vw, 17px);
  line-height: 1.8;
  color: var(--text-soft);
}

.page-about .hero-stats {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(16px, 4vw, 46px);
  margin-top: 26px;
  padding-top: 20px;
  border-top: 1px solid var(--about-line);
}

.page-about .hero-stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .stat-num {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 3.4vw, 2.15rem);
  line-height: 1;
  color: var(--c-lime);
  letter-spacing: -0.01em;
}

.page-about .stat-unit {
  font-size: 0.55em;
  margin-left: 2px;
  color: var(--c-mineral);
}

.page-about .stat-label {
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: var(--text-faint);
}

.page-about .hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

/* ---------- chapter frame ---------- */

.page-about .chapter {
  padding: clamp(38px, 6vw, 84px) 0;
  border-bottom: 1px solid var(--about-line);
}

.page-about .chapter-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(14px, 2.4vw, 34px);
}

.page-about .chapter-rail {
  display: flex;
  align-items: center;
  gap: 12px;
}

.page-about .chapter-no {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 3vw, 2.2rem);
  line-height: 1;
  letter-spacing: 0.04em;
  color: var(--c-moss);
}

.page-about .chapter-note {
  margin: 0;
  padding-left: 10px;
  border-left: 2px solid var(--c-lime);
  font-size: 12.5px;
  letter-spacing: 0.14em;
  color: var(--text-faint);
}

.page-about .chapter-body {
  min-width: 0;
}

.page-about .chapter-body h2 {
  font-size: clamp(1.55rem, 3.4vw, 2.5rem);
  max-width: 20ch;
}

.page-about .chapter-lead {
  margin: 16px 0 0;
  max-width: 56ch;
  font-size: clamp(15px, 1.7vw, 16.5px);
  line-height: 1.8;
  color: var(--text-soft);
}

/* ---------- principles ---------- */

.page-about .principles {
  list-style: none;
  margin: clamp(22px, 3vw, 34px) 0 0;
  padding: 0;
  display: grid;
  gap: 2px;
  counter-reset: principle;
}

.page-about .principles li {
  position: relative;
  padding: 20px 18px 20px 20px;
  border-left: 2px solid var(--c-moss);
  background: linear-gradient(90deg, rgba(20, 38, 29, 0.8), rgba(14, 36, 25, 0.15));
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.page-about .principles li:hover {
  border-left-color: var(--c-lime);
  transform: translateX(4px);
}

.page-about .principles h3 {
  font-size: 1.12rem;
  margin-bottom: 8px;
}

.page-about .principles p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--text-soft);
}

/* ---------- figures ---------- */

.page-about .about-figure {
  margin: clamp(24px, 3.6vw, 40px) 0 0;
}

.page-about .about-figure img,
.page-about .partner-figure img {
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  display: block;
}

.page-about .about-figure figcaption,
.page-about .partner-figure figcaption {
  margin-top: 10px;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--text-faint);
}

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

.page-about .phase-strip {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 22px;
  margin: clamp(20px, 3vw, 30px) 0 18px;
  padding: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--text-faint);
}

.page-about .phase-strip li {
  display: flex;
  align-items: center;
  gap: 8px;
}

.page-about .phase-strip .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--c-lime);
  box-shadow: 0 0 0 3px rgba(183, 255, 60, 0.14);
}

.page-about .seg {
  margin-top: 6px;
}

.page-about .seg-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .seg-tab {
  font-family: var(--font-body);
  font-size: 13.5px;
  padding: 9px 15px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--about-line);
  background: rgba(42, 48, 44, 0.5);
  color: var(--text-soft);
  cursor: pointer;
  transition: color 0.18s ease, border-color 0.18s ease, background 0.18s ease;
}

.page-about .seg-tab:hover {
  color: var(--c-chalk);
  border-color: var(--line-strong);
}

.page-about .seg-tab[aria-selected="true"] {
  background: var(--c-lime);
  border-color: var(--c-lime);
  color: #0B1F17;
  font-weight: 700;
}

.page-about .seg-panel {
  margin-top: 20px;
  padding: 20px 18px;
  border: 1px solid var(--about-line);
  border-radius: var(--radius-md);
  background: var(--surface-1);
}

.page-about .seg-panel h3 {
  font-size: 1.08rem;
  margin-bottom: 10px;
  color: var(--c-chalk);
}

.page-about .seg-panel p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.78;
  color: var(--text-soft);
}

.page-about .fact-list {
  list-style: none;
  margin: 16px 0 0;
  padding: 14px 0 0;
  border-top: 1px dashed var(--about-line);
  display: grid;
  gap: 9px;
  font-size: 14px;
  color: var(--text-soft);
}

.page-about .fact-list .data {
  display: inline-block;
  min-width: 86px;
  font-size: 12.5px;
  color: var(--c-lime);
  letter-spacing: 0.04em;
}

/* ---------- data map ---------- */

.page-about .map-board {
  list-style: none;
  margin: clamp(22px, 3vw, 34px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
}

.page-about .map-node {
  padding: 16px 16px 18px;
  border: 1px solid var(--about-line);
  border-radius: var(--radius-md);
  background: var(--surface-1);
  transition: transform 0.2s ease, border-color 0.2s ease, background 0.2s ease;
}

.page-about .map-node:hover,
.page-about .map-node:focus-within {
  transform: translateY(-3px);
  border-color: var(--line-strong);
  background: var(--surface-2);
}

.page-about .map-tag {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--c-mineral);
}

.page-about .map-node h3 {
  font-size: 1rem;
  margin-bottom: 6px;
}

.page-about .map-node p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--text-soft);
}

/* ---------- team ---------- */

.page-about .team-grid {
  list-style: none;
  margin: clamp(22px, 3vw, 34px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.page-about .team-grid li {
  padding: 18px 16px;
  border-radius: var(--radius-md);
  border: 1px solid var(--about-line);
  background: rgba(20, 38, 29, 0.65);
}

.page-about .team-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 1.9rem;
  line-height: 1;
  color: var(--c-lime);
  margin-bottom: 10px;
}

.page-about .team-grid h3 {
  font-size: 1rem;
  margin-bottom: 8px;
}

.page-about .team-grid p {
  margin: 0;
  font-size: 13.8px;
  line-height: 1.72;
  color: var(--text-soft);
}

.page-about .team-foot {
  margin: clamp(22px, 3vw, 32px) 0 0;
  padding: 16px 18px;
  border-left: 2px solid var(--c-clay);
  background: rgba(184, 107, 75, 0.08);
  font-size: 14.5px;
  line-height: 1.78;
  color: var(--text-soft);
}

/* ---------- partners ---------- */

.page-about .partner-panel {
  margin-top: clamp(22px, 3vw, 34px);
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  border: 1px solid var(--about-line);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--surface-1);
}

.page-about .partner-figure {
  position: relative;
  margin: 0;
  min-width: 0;
}

.page-about .partner-figure img {
  aspect-ratio: 16 / 10;
  height: 100%;
}

.page-about .partner-figure figcaption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  margin: 0;
  padding: 12px 14px;
  font-size: 12px;
  color: var(--c-chalk);
  background: linear-gradient(180deg, rgba(11, 31, 23, 0), rgba(11, 31, 23, 0.88));
  backdrop-filter: blur(2px);
}

.page-about .partner-body {
  padding: clamp(18px, 3vw, 28px);
  background: linear-gradient(160deg, var(--about-glass), rgba(20, 38, 29, 0.9));
  backdrop-filter: blur(6px);
}

.page-about .partner-body h3 {
  font-size: 1.1rem;
  margin-bottom: 12px;
}

.page-about .partner-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-soft);
}

.page-about .partner-list .data {
  display: inline-block;
  min-width: 76px;
  font-size: 12.5px;
  color: var(--c-lime);
}

.page-about .partner-note {
  margin: 18px 0 0;
  padding-top: 14px;
  border-top: 1px dashed var(--about-line);
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--text-faint);
}

/* ---------- faq ---------- */

.page-about .faq-list {
  margin-top: clamp(20px, 3vw, 30px);
  border-top: 1px solid var(--about-line);
}

.page-about .faq-list details {
  border-bottom: 1px solid var(--about-line);
}

.page-about .faq-list summary {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  padding: 17px 2px;
  cursor: pointer;
  font-size: 15px;
  font-weight: 600;
  line-height: 1.6;
  color: var(--c-chalk);
  list-style: none;
}

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

.page-about .faq-list summary::after {
  content: "+";
  flex: none;
  font-family: var(--font-mono);
  font-size: 19px;
  line-height: 1;
  color: var(--c-lime);
  transition: transform 0.2s ease;
}

.page-about .faq-list details[open] summary::after {
  content: "−";
}

.page-about .faq-list details[open] summary {
  color: var(--c-lime);
}

.page-about .faq-body {
  padding: 0 2px 20px;
}

.page-about .faq-body p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--text-soft);
}

.page-about .faq-link {
  display: inline-block;
  margin-top: 12px;
  font-size: 13.5px;
  color: var(--c-lime);
  text-decoration: none;
  border-bottom: 1px solid rgba(183, 255, 60, 0.4);
  padding-bottom: 2px;
}

.page-about .faq-link:hover {
  border-bottom-color: var(--c-lime);
}

/* ---------- closing ---------- */

.page-about .about-close {
  position: relative;
  padding: clamp(40px, 7vw, 86px) 0 clamp(46px, 7vw, 90px);
  background:
    linear-gradient(140deg, rgba(183, 255, 60, 0.1), transparent 55%),
    var(--c-ink-deep);
}

.page-about .about-close::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255, 90, 54, 0.55), transparent);
}

.page-about .about-close h2 {
  font-size: clamp(1.6rem, 4vw, 2.6rem);
  max-width: 18ch;
}

.page-about .about-close p {
  margin: 16px 0 0;
  max-width: 46ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--text-soft);
}

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

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

@media (min-width: 620px) {
  .page-about .map-board {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

  .page-about .index-list {
    grid-template-columns: 1fr;
  }
}

@media (min-width: 900px) {
  .page-about .hero-grid {
    grid-template-columns: minmax(150px, 2.4fr) minmax(0, 7.6fr);
    align-items: start;
  }

  .page-about .hero-index {
    position: sticky;
    top: 100px;
    padding-top: 8px;
    border-right: 1px solid var(--about-line);
    padding-right: 18px;
  }

  .page-about .chapter-grid {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
  }

  .page-about .chapter-rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
    position: sticky;
    top: 100px;
    align-self: start;
  }

  .page-about .map-board {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

  .page-about .partner-panel {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
  }

  .page-about .seg-panel {
    padding: 24px 24px;
  }
}

@media (min-width: 1140px) {
  .page-about .principles {
    gap: 6px;
  }

  .page-about .principles li {
    padding: 22px 24px 22px 24px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .principles li,
  .page-about .map-node,
  .page-about .seg-tab,
  .page-about .index-list a {
    transition: none;
  }

  .page-about .principles li:hover,
  .page-about .map-node:hover {
    transform: none;
  }
}