/* ===== 关于本站 · 页面专属样式 ===== */

.page-about {
  --about-band: 8px;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding-block: var(--space-6) var(--space-8);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-6);
  align-items: start;
}

.page-about .about-hero__text {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  min-width: 0;
}

.page-about .about-hero__lede {
  margin: 0;
  max-width: 58ch;
  color: var(--color-ink);
  font-size: var(--text-lg);
  line-height: var(--leading-body);
}

.page-about .about-hero__lede::first-letter {
  float: left;
  font-size: 2.9em;
  line-height: 0.82;
  font-weight: var(--weight-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-primary);
  margin-block-start: 0.05em;
  margin-inline-end: 0.12em;
}

.page-about .about-hero__sub {
  margin: 0;
  max-width: 56ch;
  color: var(--color-ink-soft);
  font-size: var(--text-base);
}

.page-about .about-hero__fig {
  width: 100%;
}

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

/* ---------- 通用小标题组 ---------- */

.page-about .blocks-head {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  margin-block-end: var(--space-6);
}

.page-about .blocks-head__lede {
  max-width: 72ch;
  color: var(--color-ink-soft);
}

/* ---------- 方法论 ---------- */

.page-about .why {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-4);
}

.page-about .why__head {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.page-about .why__body {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  min-width: 0;
}

.page-about .why__body p {
  margin: 0;
}

/* ---------- 阶段锚点 ---------- */

.page-about .about-toc {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1) var(--space-2);
  padding: var(--space-3);
  margin-block-end: var(--space-6);
  background: var(--color-surface-alt);
  border-radius: var(--radius-sm);
}

.page-about .about-toc a {
  padding: 4px var(--space-2);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  text-decoration: none;
  transition: background-color 180ms ease, color 180ms ease;
}

.page-about .about-toc a:hover {
  background: var(--color-highlight);
  color: var(--color-accent);
}

.page-about .about-toc a[aria-current="true"] {
  background: var(--color-primary);
  color: var(--color-primary-ink);
}

/* ---------- 纵向阶段轴 ---------- */

.page-about .stage-axis {
  display: flex;
  flex-direction: column;
}

.page-about .stage {
  scroll-margin-top: var(--space-8);
}

.page-about .stage__band {
  height: var(--about-band);
  background: var(--color-primary);
  transform: skewY(-1.2deg);
  transform-origin: left center;
}

.page-about .stage:nth-child(2n) .stage__band {
  background: var(--color-accent);
}

.page-about .stage__body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-2);
  padding-block: var(--space-6);
}

.page-about .stage__num {
  justify-self: start;
  padding: 3px var(--space-2);
  border-radius: var(--radius-sm);
  background: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
}

.page-about .stage:nth-child(2n) .stage__num {
  background: var(--color-accent);
  color: var(--color-accent-ink);
}

.page-about .stage__title {
  margin: 0;
  letter-spacing: var(--tracking-heading);
}

.page-about .stage__text {
  margin: 0;
  max-width: 74ch;
  color: var(--color-ink-soft);
}

/* ---------- 流程与分工 ---------- */

.page-about .about-flow-fig {
  margin-block-end: var(--space-6);
}

.page-about .flow {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-6);
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .flow__item {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding-block-start: var(--space-3);
  border-block-start: 4px solid var(--color-accent);
}

.page-about .flow__item:nth-child(2n) {
  border-block-start-color: var(--color-primary);
}

.page-about .flow__step {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  color: var(--color-accent);
}

.page-about .flow__item:nth-child(2n) .flow__step {
  color: var(--color-primary);
}

.page-about .flow__title {
  margin: 0;
  letter-spacing: var(--tracking-heading);
}

.page-about .flow__text {
  margin: 0;
  color: var(--color-ink-soft);
}

.page-about .flow__note {
  margin-block: var(--space-6) 0;
  max-width: 80ch;
  padding: var(--space-3) var(--space-4);
  background: var(--color-surface-alt);
  border-inline-start: 4px solid var(--color-accent);
  color: var(--color-ink-soft);
}

/* ---------- 运营原则 ---------- */

.page-about .rules {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-6);
}

.page-about .principle {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding-inline-start: var(--space-4);
  border-inline-start: 4px solid var(--color-primary);
}

.page-about .principle:nth-child(2) {
  border-inline-start-color: var(--color-accent);
}

.page-about .principle:nth-child(3) {
  border-inline-start-color: var(--color-ink-muted);
}

.page-about .principle__title {
  margin: 0;
  letter-spacing: var(--tracking-heading);
}

.page-about .principle__text {
  margin: 0;
  max-width: 62ch;
  color: var(--color-ink-soft);
}

/* ---------- 数字口径 ---------- */

.page-about .digits {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-6);
  align-items: start;
}

.page-about .digits__main {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  min-width: 0;
}

.page-about .digits__lede {
  max-width: 68ch;
  color: var(--color-ink-soft);
}

.page-about .digits__table {
  width: 100%;
  margin-block-start: var(--space-2);
}

.page-about .digits__value {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--color-primary);
}

.page-about .digits__foot {
  margin: 0;
  max-width: 72ch;
  color: var(--color-ink-muted);
  font-size: var(--text-sm);
}

.page-about .about-digits-fig {
  width: 100%;
}

/* ---------- 链接与焦点 ---------- */

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

/* ---------- 响应式 ---------- */

@media (min-width: 768px) {
  .page-about .flow {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    padding-block: var(--space-8);
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.32fr) minmax(0, 0.68fr);
    gap: var(--space-8);
  }

  .page-about .why {
    grid-template-columns: minmax(0, 0.42fr) minmax(0, 0.58fr);
    gap: var(--space-8);
  }

  .page-about .stage__body {
    grid-template-columns: 132px minmax(0, 1fr);
    column-gap: var(--space-6);
    row-gap: var(--space-2);
    align-items: start;
  }

  .page-about .stage__num {
    grid-column: 1;
    grid-row: 1 / span 2;
  }

  .page-about .stage__title,
  .page-about .stage__text {
    grid-column: 2;
  }

  .page-about .rules {
    max-width: 84ch;
  }

  .page-about .principle:nth-child(2) {
    margin-inline-start: var(--space-8);
  }

  .page-about .principle:nth-child(3) {
    margin-inline-start: calc(var(--space-8) * 2);
  }

  .page-about .digits {
    grid-template-columns: minmax(0, 1.42fr) minmax(0, 0.58fr);
    gap: var(--space-8);
  }
}

@media (min-width: 1100px) {
  .page-about .stage:nth-child(2n) .stage__body {
    margin-inline-start: var(--space-8);
  }
}
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