.page-about {
  background: var(--color-surface);
  color: var(--color-ink);
  font-family: var(--font-body);
  line-height: var(--leading-body);
}

.page-about h1,
.page-about h2,
.page-about h3 {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  margin: 0;
}

.page-about .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 700;
}

.page-about .section {
  padding-block: var(--section-y);
}

.page-about .about-narrow {
  max-width: var(--measure);
  margin-inline: auto;
}

.page-about .prose p {
  margin: 0 0 var(--space-3);
}

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

.page-about .prose a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 4px;
  text-decoration-thickness: 2px;
}

.page-about .prose a:hover,
.page-about .prose a:focus-visible {
  background: var(--color-highlight);
  color: var(--color-ink);
}

.page-about .about-figure {
  margin: 0;
  overflow: hidden;
  border-radius: var(--radius-sm);
  background: var(--color-surface-deep);
}

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

.page-about .about-figure--wide {
  aspect-ratio: 10 / 7;
}

.page-about .about-figure--flow {
  aspect-ratio: 8 / 5;
}

.page-about .about-figure--square {
  aspect-ratio: 1 / 1;
}

/* ---------- 开篇 ---------- */

.page-about .about-open {
  padding-block: var(--space-8) var(--section-y);
}

.page-about .breadcrumb {
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

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

.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--color-accent);
}

.page-about .about-open__grid {
  display: grid;
  gap: var(--space-6);
  margin-top: var(--space-6);
}

.page-about .about-open h1 {
  font-size: clamp(var(--text-2xl), 4.6vw, var(--text-4xl));
  max-width: 16ch;
  margin-top: var(--space-2);
}

.page-about .about-open .lede {
  margin: var(--space-4) 0 0;
  max-width: 44ch;
  font-size: var(--text-lg);
  color: var(--color-ink-soft);
}

@media (min-width: 900px) {
  .page-about .about-open__grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    gap: var(--space-8);
    align-items: center;
  }
}

/* 页内锚点刻度 */

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

.page-about .about-toc__list {
  display: flex;
  gap: var(--space-6);
  margin: 0;
  padding: 0 0 var(--space-1);
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-toc__list li {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  flex: none;
}

.page-about .about-toc__list li::before {
  content: "";
  display: block;
  width: 30px;
  height: 1px;
  background: var(--color-line);
}

.page-about .about-toc__list a {
  display: inline-flex;
  align-items: baseline;
  gap: var(--space-1);
  color: var(--color-ink-soft);
  text-decoration: none;
  font-size: var(--text-sm);
  white-space: nowrap;
}

.page-about .about-toc__list a .num {
  color: var(--color-ink-muted);
  font-size: var(--text-xs);
}

.page-about .about-toc__list a:hover,
.page-about .about-toc__list a:focus-visible {
  color: var(--color-accent);
}

.page-about .about-toc__list a:hover .num,
.page-about .about-toc__list a:focus-visible .num {
  color: var(--color-accent);
}

/* ---------- 缘起 ---------- */

.page-about .about-origin {
  background: var(--color-surface-alt);
}

.page-about .about-origin h2 {
  font-size: var(--text-2xl);
  margin-top: var(--space-2);
  margin-bottom: var(--space-6);
  max-width: 22ch;
}

.page-about .about-origin__prose {
  font-size: var(--text-base);
}

/* ---------- 数字带 ---------- */

.page-about .about-scale {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.page-about .about-scale__list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-6) var(--space-4);
  margin: 0;
  padding: 0;
  list-style: none;
}

@media (min-width: 820px) {
  .page-about .about-scale__list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: var(--space-4);
  }
}

.page-about .about-scale__item {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  min-width: 0;
}

.page-about .about-scale__fig {
  font-size: var(--text-3xl);
  line-height: 1;
  color: var(--color-contrast-ink);
}

.page-about .about-scale__unit {
  font-size: var(--text-base);
  color: var(--color-contrast-accent);
}

.page-about .about-scale__note {
  font-size: var(--text-sm);
  color: color-mix(in srgb, var(--color-contrast-ink) 68%, transparent);
}

/* ---------- 收录范围 ---------- */

.page-about .about-scope h2 {
  font-size: var(--text-2xl);
  margin-top: var(--space-2);
  margin-bottom: var(--space-6);
  max-width: 22ch;
}

/* ---------- 发展阶段 ---------- */

.page-about .about-stages {
  background: var(--color-primary);
  color: var(--color-primary-ink);
}

.page-about .about-stages .eyebrow {
  color: color-mix(in srgb, var(--color-primary-ink) 72%, transparent);
}

.page-about .about-stages h2 {
  font-size: var(--text-2xl);
  margin-top: var(--space-2);
  max-width: 20ch;
}

.page-about .about-stages__body {
  margin-top: var(--space-6);
  display: grid;
  gap: var(--space-6);
}

@media (min-width: 900px) {
  .page-about .about-stages__body {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    gap: var(--space-8);
    align-items: start;
  }
}

.page-about .about-stage-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 2px;
}

.page-about .about-stage-list > li {
  background: color-mix(in srgb, var(--color-primary) 86%, var(--color-contrast-surface));
}

.page-about .about-stage {
  display: block;
}

.page-about .about-stage > summary {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  cursor: pointer;
  list-style: none;
  color: var(--color-primary-ink);
}

.page-about .about-stage > summary::-webkit-details-marker {
  display: none;
}

.page-about .about-stage > summary:focus-visible {
  outline: 2px solid var(--color-primary-ink);
  outline-offset: -2px;
}

.page-about .about-stage__num {
  font-size: var(--text-sm);
  color: color-mix(in srgb, var(--color-primary-ink) 76%, transparent);
}

.page-about .about-stage__name {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
}

.page-about .about-stage__state {
  position: relative;
  width: 12px;
  height: 12px;
  flex: none;
}

.page-about .about-stage__state::before,
.page-about .about-stage__state::after {
  content: "";
  position: absolute;
  background: currentColor;
}

.page-about .about-stage__state::before {
  left: 0;
  right: 0;
  top: 5px;
  height: 2px;
}

.page-about .about-stage__state::after {
  top: 0;
  bottom: 0;
  left: 5px;
  width: 2px;
  transition: opacity 180ms ease;
}

.page-about .about-stage[open] .about-stage__state::after {
  opacity: 0;
}

.page-about .about-stage__body {
  padding: 0 var(--space-4) var(--space-4);
  color: color-mix(in srgb, var(--color-primary-ink) 84%, transparent);
  font-size: var(--text-sm);
  max-width: 62ch;
}

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

.page-about .about-stages .about-figure {
  background: color-mix(in srgb, var(--color-primary) 70%, var(--color-contrast-surface));
}

/* ---------- 能力边界 ---------- */

.page-about .about-limits h2 {
  font-size: var(--text-2xl);
  margin-top: var(--space-2);
  max-width: 20ch;
}

.page-about .about-limits__lede {
  margin: var(--space-3) 0 0;
  color: var(--color-ink-soft);
  max-width: 46ch;
}

.page-about .about-limits__list {
  margin: var(--space-6) 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: var(--space-2);
}

@media (min-width: 860px) {
  .page-about .about-limits__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--space-2) var(--space-4);
  }
}

.page-about .about-limit {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  column-gap: var(--space-3);
  padding: var(--space-3) var(--space-3);
  border-radius: var(--radius-sm);
  transition: background-color 180ms ease;
}

.page-about .about-limit:hover,
.page-about .about-limit:focus-within {
  background: var(--color-highlight);
}

.page-about .about-limit__num {
  grid-row: 1 / span 2;
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
  padding-top: 3px;
}

.page-about .about-limit__title {
  font-size: var(--text-base);
  margin: 0;
}

.page-about .about-limit__text {
  margin: var(--space-1) 0 0;
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
}

/* ---------- 团队 ---------- */

.page-about .about-team {
  background: var(--color-surface-alt);
}

.page-about .about-team__grid {
  display: grid;
  gap: var(--space-6);
}

@media (min-width: 900px) {
  .page-about .about-team__grid {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
    gap: var(--space-8);
    align-items: start;
  }
}

.page-about .about-team h2 {
  font-size: var(--text-2xl);
  margin-top: var(--space-2);
  margin-bottom: var(--space-6);
  max-width: 20ch;
}

.page-about .about-team__list {
  margin-top: var(--space-6);
  display: grid;
  gap: 2px;
}

.page-about .about-team .data-row {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  column-gap: var(--space-3);
  row-gap: var(--space-1);
  padding: var(--space-3) var(--space-3);
  background: var(--color-surface);
}

.page-about .about-team .data-row__id {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  color: var(--color-accent);
  font-size: var(--text-sm);
  padding-top: 3px;
}

.page-about .about-team .data-row__title {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-base);
}

.page-about .about-team .data-row__meta {
  grid-column: 2;
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
}

/* ---------- 栏目分工 ---------- */

.page-about .about-roles {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.page-about .about-roles .eyebrow {
  color: color-mix(in srgb, var(--color-contrast-ink) 70%, transparent);
}

.page-about .about-roles h2 {
  font-size: var(--text-2xl);
  margin-top: var(--space-2);
  max-width: 18ch;
}

.page-about .about-roles__lede {
  margin: var(--space-3) 0 0;
  max-width: 46ch;
  color: color-mix(in srgb, var(--color-contrast-ink) 78%, transparent);
}

.page-about .about-roles__list {
  margin: var(--space-6) 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 2px;
}

@media (min-width: 860px) {
  .page-about .about-roles__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.page-about .about-role__link {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  column-gap: var(--space-3);
  row-gap: var(--space-1);
  padding: var(--space-4);
  background: color-mix(in srgb, var(--color-contrast-surface) 82%, var(--color-primary));
  color: inherit;
  text-decoration: none;
  height: 100%;
  transition: background-color 180ms ease;
}

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

.page-about .about-role__tag {
  font-size: var(--text-xs);
  color: var(--color-contrast-accent);
}

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

.page-about .about-role__name {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
}

.page-about .about-role__desc {
  grid-column: 2;
  font-size: var(--text-sm);
  color: color-mix(in srgb, var(--color-contrast-ink) 74%, transparent);
}

.page-about .about-role__link:hover .about-role__desc,
.page-about .about-role__link:focus-visible .about-role__desc {
  color: color-mix(in srgb, var(--color-primary-ink) 82%, transparent);
}

/* ---------- 原则清单 ---------- */

.page-about .about-principles h2 {
  font-size: var(--text-2xl);
  margin-top: var(--space-2);
  margin-bottom: var(--space-6);
  max-width: 18ch;
}

.page-about .about-principles__list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: var(--space-2);
}

.page-about .about-principle {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  column-gap: var(--space-4);
  align-items: baseline;
  padding-block: var(--space-2);
}

.page-about .about-principle__num {
  font-size: var(--text-sm);
  color: var(--color-accent);
}

.page-about .about-principle p {
  margin: 0;
  font-size: var(--text-base);
}

@media (max-width: 480px) {
  .page-about .about-open h1 {
    font-size: var(--text-2xl);
  }

  .page-about .about-scale__fig {
    font-size: var(--text-2xl);
  }

  .page-about .about-stage > summary {
    padding: var(--space-3);
    gap: var(--space-2);
  }

  .page-about .about-stage__name {
    font-size: var(--text-base);
  }
}