.page-about .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  padding-top: var(--space-4);
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

.page-about .breadcrumb a {
  color: var(--color-primary);
  text-decoration: none;
}

.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  text-decoration: underline;
}

/* 首屏：深色记分板式开场 */
.page-about .about-open {
  margin-top: var(--space-4);
  padding: var(--space-8) 0;
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.page-about .about-open__eyebrow {
  margin: 0;
  font-size: var(--text-sm);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-contrast-accent);
}

.page-about .about-open__title {
  margin: var(--space-3) 0 0;
  max-width: 22ch;
  font-family: var(--font-heading);
  font-size: var(--text-4xl);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: 0.04em;
  color: var(--color-contrast-ink);
}

.page-about .about-open__lede {
  margin: var(--space-4) 0 0;
  max-width: 62ch;
  font-size: var(--text-lg);
  line-height: var(--leading-body);
  color: color-mix(in srgb, var(--color-contrast-ink) 86%, transparent);
}

.page-about .about-figures {
  list-style: none;
  margin: var(--space-6) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  border-top: var(--border-thin) solid var(--color-contrast-line);
}

.page-about .about-figures > li {
  padding: var(--space-3) 0;
  border-bottom: var(--border-thin) solid var(--color-contrast-line);
}

.page-about .about-figures .fig-num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--text-2xl);
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--color-contrast-ink);
}

.page-about .about-figures .fig-label {
  display: block;
  margin-top: var(--space-1);
  font-size: var(--text-sm);
  line-height: 1.6;
  color: color-mix(in srgb, var(--color-contrast-ink) 76%, transparent);
}

/* 章节引导句 */
.page-about .about-intro {
  max-width: var(--measure);
  margin: 0 0 var(--space-6);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

/* 叙事段落 */
.page-about .about-prose {
  max-width: var(--measure);
}

.page-about .about-prose p {
  margin: 0 0 var(--space-4);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink);
}

.page-about .about-prose a {
  color: var(--color-primary);
  text-underline-offset: 3px;
}

/* 图片 */
.page-about .about-figure {
  margin: 0 0 var(--space-6);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: var(--radius-lg);
  background: var(--color-surface-deep);
}

.page-about .about-figure figcaption {
  margin-top: var(--space-2);
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-ink-muted);
}

/* 发展阶段 */
.page-about .stage-list {
  border-top: 2px solid var(--color-primary);
}

.page-about .stage {
  border-bottom: var(--border-thin) solid var(--color-line);
}

.page-about .stage[open] {
  border-bottom-color: var(--color-ink-muted);
}

.page-about .stage__head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: baseline;
  gap: var(--space-3);
  padding: var(--space-4) 0;
  cursor: pointer;
  list-style: none;
}

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

.page-about .stage__head:hover .stage__name,
.page-about .stage__head:focus-visible .stage__name {
  color: var(--color-primary);
}

.page-about .stage__index {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  color: var(--color-primary);
}

.page-about .stage__name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  letter-spacing: 0.1em;
  color: var(--color-ink);
  transition: color 120ms ease-out;
}

.page-about .stage__body {
  padding: 0 0 var(--space-4);
}

.page-about .stage__body p {
  margin: 0;
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

.page-about .stage__meta {
  margin: var(--space-4) 0 0;
  display: grid;
  gap: var(--space-2);
}

.page-about .stage__meta > div {
  display: grid;
  grid-template-columns: 92px minmax(0, 1fr);
  gap: var(--space-2);
  padding-top: var(--space-2);
  border-top: var(--border-thin) solid var(--color-line);
}

.page-about .stage__meta dt {
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}

.page-about .stage__meta dd {
  margin: 0;
  font-size: var(--text-sm);
  line-height: 1.7;
  color: var(--color-ink);
}

/* 能力边界 */
.page-about .boundary {
  border-top: 2px solid var(--color-primary);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.page-about .boundary__summary {
  padding: var(--space-3) 0;
  cursor: pointer;
  list-style: none;
  font-size: var(--text-sm);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
}

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

.page-about .boundary__summary:hover,
.page-about .boundary__summary:focus-visible {
  color: var(--color-primary);
}

.page-about .boundary__list {
  list-style: none;
  margin: 0;
  padding: 0 0 var(--space-4);
  display: grid;
  gap: var(--space-4);
}

.page-about .boundary__list > li {
  border-left: 3px solid var(--color-primary);
  padding-left: var(--space-3);
}

.page-about .boundary__term {
  display: block;
  margin-bottom: var(--space-1);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  letter-spacing: 0.06em;
  color: var(--color-ink);
}

.page-about .boundary__desc {
  margin: 0;
  max-width: 64ch;
  font-size: var(--text-base);
  line-height: 1.7;
  color: var(--color-ink-soft);
}

/* 两栏排版 */
.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-6);
  align-items: start;
}

.page-about .about-figure--side {
  margin-bottom: 0;
}

/* 运营原则 */
.page-about .principle-list {
  list-style: none;
  counter-reset: principle;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--space-4);
}

.page-about .principle-list > li {
  counter-increment: principle;
  position: relative;
  padding: var(--space-3) 0 0 var(--space-6);
  border-top: var(--border-thin) solid var(--color-line);
}

.page-about .principle-list > li::before {
  content: "0" counter(principle);
  position: absolute;
  left: 0;
  top: var(--space-3);
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  color: var(--color-primary);
}

.page-about .principle__name {
  margin: 0 0 var(--space-1);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  letter-spacing: 0.06em;
  line-height: var(--leading-heading);
  color: var(--color-ink);
}

.page-about .principle__desc {
  margin: 0;
  max-width: 56ch;
  font-size: var(--text-base);
  line-height: 1.75;
  color: var(--color-ink-soft);
}

/* 团队分工表 */
.page-about .team-table-wrap {
  max-width: 100%;
  overflow-x: auto;
  border-radius: var(--radius-md);
}

.page-about .team-table {
  width: 100%;
  min-width: 560px;
  border-collapse: collapse;
  font-size: var(--text-sm);
}

.page-about .team-table caption {
  padding-bottom: var(--space-2);
  text-align: left;
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}

.page-about .team-table thead th {
  padding: var(--space-2) var(--space-3) var(--space-2) 0;
  border-top: 2px solid var(--color-ink);
  border-bottom: var(--border-thin) solid var(--color-ink);
  text-align: left;
  font-weight: var(--weight-heading);
  letter-spacing: 0.06em;
  color: var(--color-ink);
  white-space: nowrap;
}

.page-about .team-table tbody th,
.page-about .team-table tbody td {
  padding: var(--space-2) var(--space-3) var(--space-2) 0;
  border-bottom: var(--border-thin) solid var(--color-line);
  vertical-align: top;
  line-height: 1.5;
  text-align: left;
  color: var(--color-ink-soft);
}

.page-about .team-table tbody th {
  font-weight: var(--weight-heading);
  color: var(--color-ink);
  white-space: nowrap;
}

.page-about .team-table tbody tr:hover th,
.page-about .team-table tbody tr:hover td {
  background: var(--color-primary-soft);
}

@media (min-width: 760px) {
  .page-about .about-open {
    padding: var(--section-y-lg) 0;
  }

  .page-about .about-figures {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: var(--space-6);
  }

  .page-about .about-figures > li {
    padding-right: var(--space-2);
  }

  .page-about .boundary__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: var(--space-6);
  }

  .page-about .stage__meta > div {
    grid-template-columns: 112px minmax(0, 1fr);
  }
}

@media (min-width: 1000px) {
  .page-about .about-open__title {
    max-width: 26ch;
  }

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

  .page-about .about-split {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: var(--space-8);
  }

  .page-about .about-split--media-first {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  }

  .page-about .stage__head {
    grid-template-columns: 128px minmax(0, 1fr);
    gap: var(--space-4);
  }

  .page-about .stage__body {
    padding-left: 128px;
  }

  .page-about .stage__meta {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: var(--space-6);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .stage__name {
    transition: none;
  }
}