.page-about {
  background: var(--abyss-950);
  color: var(--paper-050);
  overflow-x: hidden;
}

.page-about .about-wrap {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--pad-x);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding-block: clamp(18px, 3vw, 28px) clamp(30px, 5vw, 58px);
  border-bottom: 1px solid var(--line-600);
  background:
    radial-gradient(120% 80% at 88% -20%, rgba(51, 225, 210, 0.16), transparent 58%),
    radial-gradient(90% 70% at -5% 115%, rgba(255, 106, 43, 0.09), transparent 62%);
}

.page-about .breadcrumb {
  color: var(--mist-400);
  font-size: var(--fs-12);
  letter-spacing: 0.02em;
}

.page-about .about-hero__eyebrow {
  margin: clamp(20px, 3vw, 34px) 0 0;
  color: var(--mist-400);
}

.page-about .about-hero__title {
  margin: clamp(12px, 2vw, 20px) 0 clamp(14px, 2vw, 20px);
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: var(--fs-64);
  line-height: 1.14;
  letter-spacing: -0.01em;
  max-width: 15em;
  text-wrap: balance;
}

.page-about .about-hero__lead {
  margin: 0;
  max-width: 62ch;
  font-size: var(--fs-20);
  line-height: 1.78;
  color: var(--mist-400);
}

.page-about .about-facts {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(22px, 3.2vw, 38px) 0 0;
  padding: 0;
  background: var(--line-600);
  border: 1px solid var(--line-600);
}

.page-about .about-facts__item {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
  padding: clamp(12px, 1.6vw, 18px);
  background: var(--abyss-950);
}

.page-about .about-facts__num {
  font-family: var(--font-mono);
  font-size: var(--fs-28);
  line-height: 1;
  color: var(--cyan-400);
  font-variant-numeric: tabular-nums;
}

.page-about .about-facts__key {
  font-size: var(--fs-14);
  color: var(--mist-400);
  line-height: 1.5;
}

/* ---------- 章节索引 ---------- */
.page-about .about-index {
  padding-block: clamp(16px, 2.4vw, 26px);
  border-bottom: 1px solid var(--line-600);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px clamp(14px, 2.6vw, 30px);
}

.page-about .about-index__link {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  padding-bottom: 3px;
  font-size: var(--fs-14);
  color: var(--mist-400);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.18s ease, border-color 0.18s ease;
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  color: var(--cyan-400);
  border-bottom-color: var(--cyan-400);
}

.page-about .about-index__no {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  opacity: 0.7;
}

/* ---------- 编号长文章节 ---------- */
.page-about .chapter {
  border-top: 1px solid var(--line-600);
  padding-block: clamp(34px, 5.6vw, 74px);
}

.page-about .about-index + .chapter {
  border-top: 0;
}

.page-about .chapter__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(8px, 1.4vw, 18px) clamp(16px, 3vw, 48px);
}

.page-about .chapter__no {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(2.4rem, 7vw, 5.2rem);
  line-height: 0.86;
  letter-spacing: -0.02em;
  color: var(--line-600);
  font-variant-numeric: tabular-nums;
}

@supports (-webkit-text-stroke: 1px #000) {
  .page-about .chapter__no {
    color: transparent;
    -webkit-text-stroke: 1px var(--line-600);
  }
}

.page-about .chapter__body {
  min-width: 0;
}

.page-about .chapter__title {
  margin: 0 0 clamp(12px, 2vw, 20px);
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: var(--fs-40);
  line-height: 1.28;
  letter-spacing: -0.005em;
}

.page-about .chapter__text {
  max-width: 68ch;
  margin: 0 0 1.05em;
  font-size: var(--fs-16);
  line-height: 1.86;
}

.page-about .chapter__text:last-child {
  margin-bottom: 0;
}

.page-about .chapter__link {
  color: var(--cyan-400);
  text-decoration: none;
  border-bottom: 1px solid var(--line-600);
  transition: border-color 0.18s ease, color 0.18s ease;
}

.page-about .chapter__link:hover,
.page-about .chapter__link:focus-visible {
  color: var(--cyan-200);
  border-bottom-color: var(--cyan-400);
}

.page-about .chapter__list {
  list-style: none;
  margin: 0 0 1.05em;
  padding: 0;
  max-width: 68ch;
  display: grid;
  gap: 10px;
}

.page-about .chapter__list li {
  position: relative;
  padding-left: 24px;
  font-size: var(--fs-16);
  line-height: 1.78;
}

.page-about .chapter__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.78em;
  width: 13px;
  height: 1px;
  background: var(--cyan-400);
}

.page-about .chapter__list strong {
  color: var(--cyan-200);
  font-weight: 600;
}

/* ---------- 图版 ---------- */
.page-about .plate {
  position: relative;
  margin: clamp(22px, 3.4vw, 40px) 0 0;
  max-width: 100%;
}

.page-about .plate::before {
  content: "";
  position: absolute;
  inset: 9px -6px -9px 6px;
  border: 1px solid var(--line-600);
  pointer-events: none;
}

.page-about .plate img {
  position: relative;
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border: 1px solid var(--line-600);
}

.page-about .plate--tall img {
  aspect-ratio: 4 / 5;
}

.page-about .plate--tall {
  max-width: 520px;
}

.page-about .plate__caption {
  position: relative;
  margin-top: clamp(14px, 2vw, 18px);
  font-size: var(--fs-12);
  line-height: 1.7;
  color: var(--mist-400);
  letter-spacing: 0.02em;
}

/* ---------- 数字看板 ---------- */
.page-about .ledger {
  margin-block: clamp(12px, 2vw, 20px);
  padding-block: clamp(30px, 5vw, 64px);
  border-top: 1px solid var(--line-600);
  border-bottom: 1px solid var(--line-600);
  background: linear-gradient(158deg, var(--abyss-900) 0%, var(--tide-800) 100%);
}

.page-about .ledger__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px clamp(14px, 2vw, 24px);
  margin-bottom: clamp(16px, 2.6vw, 28px);
}

.page-about .ledger__title {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: var(--fs-28);
  line-height: 1.3;
}

.page-about .ledger__hint {
  margin: 0;
  font-size: var(--fs-12);
  letter-spacing: 0.04em;
  color: var(--mist-400);
}

.page-about .ledger__grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line-600);
  border: 1px solid var(--line-600);
}

.page-about .ledger__cell {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-width: 0;
  padding: clamp(14px, 2vw, 22px);
  background: var(--abyss-950);
}

.page-about .ledger__num {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 3.6vw, 2.2rem);
  line-height: 1;
  color: var(--cyan-400);
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.01em;
}

.page-about .ledger__num small {
  font-size: 0.48em;
  margin-left: 2px;
  color: var(--cyan-200);
}

.page-about .ledger__label {
  font-size: var(--fs-14);
  font-weight: 700;
  line-height: 1.4;
}

.page-about .ledger__note {
  font-size: var(--fs-12);
  line-height: 1.65;
  color: var(--mist-400);
  opacity: 0.62;
  transition: opacity 0.18s ease, transform 0.18s ease;
}

.page-about .ledger__cell:hover .ledger__note,
.page-about .ledger__cell:focus-within .ledger__note {
  opacity: 1;
  transform: translateY(-1px);
}

/* ---------- 发展节点折叠 ---------- */
.page-about .about-timeline {
  margin-top: clamp(6px, 1vw, 10px);
}

.page-about .about-timeline__list {
  list-style: none;
  margin: clamp(16px, 2.6vw, 26px) 0 0;
  padding: 0;
  max-width: 76ch;
}

.page-about .about-timeline__item {
  border-top: 1px solid var(--line-600);
}

.page-about .about-timeline__item:last-child {
  border-bottom: 1px solid var(--line-600);
}

.page-about .about-timeline__item details > summary {
  list-style: none;
}

.page-about .about-timeline__summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px clamp(10px, 2vw, 20px);
  padding: clamp(13px, 1.9vw, 20px) 0;
  cursor: pointer;
  font-weight: 700;
  font-size: var(--fs-16);
  line-height: 1.5;
  color: var(--paper-050);
}

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

.page-about .about-timeline__summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: var(--fs-16);
  color: var(--cyan-400);
}

.page-about .about-timeline__item details[open] .about-timeline__summary::after {
  content: "–";
}

.page-about .about-timeline__summary:hover {
  color: var(--cyan-200);
}

.page-about .about-timeline__era {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.04em;
  color: var(--cyan-400);
  padding: 2px 8px;
  border: 1px solid var(--line-600);
  white-space: nowrap;
}

.page-about .about-timeline__body {
  margin: 0;
  padding: 0 0 clamp(14px, 2vw, 22px);
  max-width: 66ch;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--mist-400);
}

/* ---------- 收尾行动 ---------- */
.page-about .about-cta {
  padding-block: clamp(36px, 6vw, 82px);
  border-top: 1px solid var(--line-600);
  background: radial-gradient(90% 120% at 10% 0%, rgba(51, 225, 210, 0.1), transparent 60%);
}

.page-about .about-cta__title {
  margin: 0 0 clamp(12px, 2vw, 16px);
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: var(--fs-40);
  line-height: 1.26;
  max-width: 22em;
  text-wrap: balance;
}

.page-about .about-cta__text {
  margin: 0 0 clamp(20px, 3vw, 30px);
  max-width: 58ch;
  font-size: var(--fs-16);
  line-height: 1.8;
  color: var(--mist-400);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px clamp(12px, 2vw, 18px);
}

/* ---------- 断点 ---------- */
@media (min-width: 760px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .plate::before {
    inset: 13px -12px -13px 12px;
  }
}

@media (min-width: 900px) {
  .page-about .chapter__grid {
    grid-template-columns: minmax(92px, 168px) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .chapter__no {
    position: sticky;
    top: 24px;
  }

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

  .page-about .plate--offset {
    margin-left: clamp(0px, 4vw, 54px);
  }
}

@media (min-width: 1100px) {
  .page-about .about-timeline__list {
    max-width: 82ch;
  }
}

@media (max-width: 600px) {
  .page-about .about-hero__lead {
    font-size: var(--fs-16);
  }

  .page-about .ledger__num {
    font-size: 1.45rem;
  }

  .page-about .about-cta__actions .btn {
    width: 100%;
    text-align: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-index__link,
  .page-about .chapter__link,
  .page-about .ledger__note {
    transition: none;
  }
}
<<<PAGE_CSS_END>>>