.page-about {
  display: block;
  --about-rail-w: 76px;
  --about-line: var(--ink-700);
}

/* 面包屑留白 */
.page-about .about-crumb {
  padding-top: clamp(16px, 2.4vw, 28px);
  padding-bottom: clamp(10px, 1.6vw, 18px);
}

/* 首屏 */
.page-about .about-hero {
  border-bottom: 1px solid var(--about-line);
  background:
    radial-gradient(120% 90% at 12% 0%, rgba(29, 51, 80, 0.55) 0%, rgba(11, 22, 34, 0) 62%);
}

.page-about .about-hero__inner {
  position: relative;
  padding-top: clamp(30px, 5vw, 62px);
  padding-bottom: clamp(28px, 4vw, 52px);
}

.page-about .about-hero__inner::before {
  content: "";
  position: absolute;
  top: 0;
  left: var(--gutter);
  right: var(--gutter);
  height: 9px;
  border-top: 1px solid var(--ink-600);
  background-image: repeating-linear-gradient(90deg, var(--ink-600) 0 1px, transparent 1px 22px);
  opacity: 0.75;
}

.page-about .about-hero__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 16px;
}

.page-about .about-hero__stamp {
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  color: var(--silver-dim);
}

.page-about .about-hero__title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(2rem, 6.2vw, 3.9rem);
  line-height: 1.06;
  letter-spacing: 0.04em;
  color: var(--paper);
  margin: 0.45em 0 0.4em;
}

.page-about .about-hero__lead {
  max-width: 60ch;
  margin: 0;
  color: var(--silver);
  font-size: clamp(1rem, 1.5vw, 1.0625rem);
  line-height: 1.82;
}

.page-about .about-hero__note {
  max-width: 60ch;
  margin: 12px 0 0;
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  color: var(--silver-dark);
}

/* 统计刻度 */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: clamp(26px, 3.6vw, 42px);
  border: 1px solid var(--about-line);
  background: var(--about-line);
}

.page-about .about-stats__item {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: clamp(14px, 2vw, 22px);
  background: var(--ink-900);
}

.page-about .about-stats__num {
  font-size: clamp(1.75rem, 4.4vw, 2.5rem);
  line-height: 1;
  letter-spacing: 0.01em;
  color: var(--amber-soft);
}

.page-about .about-stats__label {
  font-size: 0.8125rem;
  letter-spacing: 0.14em;
  color: var(--silver-dim);
}

/* 阶段索引横条 */
.page-about .about-axis__inner {
  padding-top: clamp(20px, 3vw, 32px);
  padding-bottom: clamp(22px, 3vw, 34px);
}

.page-about .about-axis__caption {
  margin: 0 0 16px;
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--silver-dim);
}

.page-about .about-axis__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.page-about .about-axis__link {
  position: relative;
  display: grid;
  gap: 3px;
  padding-top: 16px;
  text-decoration: none;
  color: inherit;
  transition: transform var(--dur) var(--ease);
}

.page-about .about-axis__link::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 7px;
  border-top: 1px solid var(--about-line);
  background-image: repeating-linear-gradient(90deg, var(--ink-600) 0 1px, transparent 1px 11px);
}

.page-about .about-axis__link::after {
  content: "";
  position: absolute;
  top: -3px;
  left: 0;
  width: 8px;
  height: 8px;
  background: var(--amber);
  opacity: 0;
  transition: opacity var(--dur) var(--ease);
}

.page-about .about-axis__link:hover::after,
.page-about .about-axis__link:focus-visible::after {
  opacity: 1;
}

.page-about .about-axis__link:hover {
  transform: translateY(-2px);
}

.page-about .about-axis__num {
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  color: var(--amber);
}

.page-about .about-axis__range {
  font-size: 1.0625rem;
  letter-spacing: 0.02em;
  color: var(--paper);
}

.page-about .about-axis__name {
  font-size: 0.875rem;
  color: var(--silver-dim);
  transition: color var(--dur) var(--ease);
}

.page-about .about-axis__link:hover .about-axis__name,
.page-about .about-axis__link:focus-visible .about-axis__name {
  color: var(--silver);
}

/* 阶段长卷 */
.page-about .stage {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(14px, 2.4vw, 26px);
  padding-top: clamp(34px, 6vw, 68px);
  padding-bottom: clamp(34px, 6vw, 68px);
  border-top: 1px solid var(--about-line);
  scroll-margin-top: 28px;
}

.page-about .stage__rail {
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: 12px;
}

.page-about .stage__badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 46px;
  height: 30px;
  padding: 0 9px;
  background: var(--ink-800);
  border: 1px solid var(--about-line);
  border-left: 3px solid var(--amber);
  color: var(--amber-soft);
  font-size: 0.875rem;
  letter-spacing: 0.1em;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .stage:hover .stage__badge {
  border-left-color: var(--amber-soft);
  color: var(--paper);
}

.page-about .stage__range {
  font-size: 0.75rem;
  line-height: 1.55;
  letter-spacing: 0.12em;
  color: var(--silver-dark);
}

.page-about .stage__body > *:last-child {
  margin-bottom: 0;
}

.page-about .stage__year {
  margin: 0 0 4px;
  font-size: clamp(2.6rem, 9vw, 5.2rem);
  font-weight: 500;
  line-height: 0.94;
  letter-spacing: -0.01em;
  color: var(--ink-600);
}

.page-about .stage__title {
  margin: 0 0 16px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.375rem, 3.4vw, 1.9375rem);
  letter-spacing: 0.05em;
  color: var(--paper);
}

.page-about .stage__text {
  max-width: 62ch;
  margin: 0 0 14px;
  color: var(--silver);
  line-height: 1.82;
}

.page-about .stage__figure {
  margin: clamp(20px, 3vw, 30px) 0 0;
}

/* 数据点行 */
.page-about .points {
  list-style: none;
  margin: clamp(20px, 3vw, 28px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  border: 1px solid var(--about-line);
  background: var(--about-line);
}

.page-about .points__item {
  display: flex;
  flex-direction: column;
  gap: 5px;
  padding: 12px 14px;
  background: var(--ink-900);
}

.page-about .points__key {
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  color: var(--silver-dim);
}

.page-about .points__val {
  font-size: 1.0625rem;
  letter-spacing: 0.02em;
  color: var(--amber-soft);
}

/* 纸白摘录块 */
.page-about .pull {
  max-width: 62ch;
  margin: clamp(6px, 1.6vw, 14px) 0;
  padding: clamp(18px, 3vw, 30px) clamp(18px, 3vw, 36px);
  background: var(--paper);
  color: var(--ink-900);
  border: 1px solid var(--ink-700);
  box-shadow: 9px 9px 0 rgba(29, 51, 80, 0.5);
}

.page-about .pull__label {
  display: block;
  margin-bottom: 10px;
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  color: var(--ink-600);
}

.page-about .pull__text {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.0625rem, 2.3vw, 1.3125rem);
  line-height: 1.62;
  letter-spacing: 0.02em;
}

/* 阶梯图 */
.page-about .chart {
  margin: clamp(22px, 3.2vw, 34px) 0 0;
}

.page-about .chart__svg {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .chart__caption {
  margin-top: 10px;
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  color: var(--silver-dim);
}

/* 区域记录区 */
.page-about .zone {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(20px, 3vw, 34px);
  padding-top: clamp(34px, 6vw, 66px);
  padding-bottom: clamp(34px, 6vw, 66px);
  border-top: 1px solid var(--about-line);
}

.page-about .zone__title {
  margin: 0 0 16px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.375rem, 3.4vw, 1.9375rem);
  letter-spacing: 0.05em;
  color: var(--paper);
}

.page-about .zone__para {
  max-width: 62ch;
  margin: 0 0 14px;
  color: var(--silver);
  line-height: 1.82;
}

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

/* 维护机制 */
.page-about .ledger {
  padding-top: clamp(34px, 6vw, 66px);
  padding-bottom: clamp(34px, 6vw, 66px);
  border-top: 1px solid var(--about-line);
}

.page-about .ledger__list {
  list-style: none;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  border: 1px solid var(--about-line);
  background: var(--about-line);
}

.page-about .ledger__item {
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr);
  gap: 14px;
  padding: clamp(14px, 2.2vw, 22px);
  background: var(--ink-900);
  transition: background var(--dur) var(--ease);
}

.page-about .ledger__item:hover {
  background: var(--ink-800);
}

.page-about .ledger__idx {
  display: inline-flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 3px;
  font-size: 0.875rem;
  letter-spacing: 0.1em;
  color: var(--amber);
}

.page-about .ledger__title {
  margin: 0 0 7px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.0625rem;
  letter-spacing: 0.05em;
  color: var(--paper);
}

.page-about .ledger__text {
  margin: 0;
  max-width: 64ch;
  color: var(--silver);
  line-height: 1.78;
}

/* 编号引用 */
.page-about .coding {
  padding-top: clamp(34px, 6vw, 66px);
  padding-bottom: clamp(34px, 6vw, 66px);
  border-top: 1px solid var(--about-line);
}

.page-about .coding__lead {
  max-width: 62ch;
  margin: 0 0 22px;
  color: var(--silver);
  line-height: 1.82;
}

.page-about .code-parts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  border: 1px solid var(--about-line);
  background: var(--about-line);
}

.page-about .code-parts__item {
  display: grid;
  gap: 7px;
  padding: clamp(16px, 2.4vw, 24px);
  background: var(--ink-800);
}

.page-about .code-parts__key {
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  color: var(--silver-dim);
}

.page-about .code-parts__val {
  font-size: clamp(1.5rem, 4vw, 2rem);
  line-height: 1;
  letter-spacing: 0.04em;
  color: var(--amber-soft);
}

.page-about .code-parts__desc {
  font-size: 0.875rem;
  line-height: 1.75;
  color: var(--silver);
}

.page-about .coding__note {
  max-width: 62ch;
  margin: 20px 0 0;
  padding-left: 14px;
  border-left: 2px solid var(--red);
  font-size: 0.875rem;
  line-height: 1.8;
  color: var(--silver-dim);
}

/* 延伸入口 */
.page-about .routes {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  border-top: 1px solid var(--about-line);
  border-bottom: 1px solid var(--about-line);
  background: var(--about-line);
}

.page-about .routes__link {
  display: grid;
  gap: 6px;
  padding: clamp(16px, 2.4vw, 24px) clamp(14px, 2vw, 22px);
  background: var(--ink-900);
  text-decoration: none;
  color: inherit;
  transition: background var(--dur) var(--ease);
}

.page-about .routes__link:hover {
  background: var(--ink-800);
}

.page-about .routes__label {
  font-size: 0.9375rem;
  letter-spacing: 0.14em;
  color: var(--amber-soft);
}

.page-about .routes__desc {
  font-size: 0.8125rem;
  line-height: 1.7;
  color: var(--silver-dim);
}

/* 中屏 */
@media (min-width: 640px) {
  .page-about .points {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

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

/* 宽屏：编辑部式窄栏 + 宽内容区 */
@media (min-width: 760px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-axis__list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 22px;
  }

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

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

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

@media (min-width: 900px) {
  .page-about .stage {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(22px, 3.2vw, 48px);
  }

  .page-about .stage__rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
    position: sticky;
    top: 32px;
  }

  .page-about .stage__range {
    font-size: 0.8125rem;
  }

  .page-about .zone {
    grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
    gap: clamp(28px, 4vw, 56px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-axis__link,
  .page-about .stage__badge,
  .page-about .ledger__item,
  .page-about .routes__link {
    transition: none;
  }

  .page-about .about-axis__link:hover {
    transform: none;
  }
}
<<<END>>>