.page-about {
  display: block;
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  padding-block: var(--space-2) 0;
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
}

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

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

.page-about .breadcrumb [aria-current="page"] {
  color: var(--color-ink);
}

.page-about .breadcrumb-sep {
  color: var(--color-line);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: var(--space-4) var(--space-6);
  background-color: var(--color-surface-alt);
  background-image:
    repeating-linear-gradient(90deg, color-mix(in srgb, var(--color-line) 70%, transparent) 0 1px, transparent 1px 72px),
    repeating-linear-gradient(0deg, color-mix(in srgb, var(--color-line) 70%, transparent) 0 1px, transparent 1px 72px);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset-inline-start: 0;
  bottom: 0;
  width: min(46%, 460px);
  height: calc(var(--border-thin) * 3);
  background: linear-gradient(90deg, var(--color-accent), color-mix(in srgb, var(--color-accent) 0%, transparent));
}

.page-about .about-hero-inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: var(--space-4);
}

.page-about .about-hero-lead h1 {
  margin: 0 0 var(--space-2);
  font-family: var(--font-heading);
  font-size: var(--text-2xl);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

.page-about .about-hero-lead .eyebrow {
  margin: 0 0 var(--space-2);
}

/* 首屏指标块 */
.page-about .about-figures {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  padding: var(--space-3);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border: var(--border-thin) solid var(--color-contrast-line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-2);
}

.page-about .about-figure {
  padding-block: var(--space-2);
  border-top: var(--border-thin) solid var(--color-contrast-line);
}

.page-about .about-figure:first-child {
  padding-block-start: 0;
  border-top: 0;
}

.page-about .about-figure-value {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: var(--weight-heading);
  line-height: 1.04;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  color: var(--color-contrast-ink);
}

.page-about .about-figure--key .about-figure-value {
  color: var(--color-contrast-accent);
}

.page-about .about-figure-label {
  display: block;
  margin-top: var(--space-1);
  font-size: var(--text-sm);
  color: color-mix(in srgb, var(--color-contrast-ink) 72%, transparent);
}

/* ---------- 页内锚点条 ---------- */
.page-about .about-jump {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1) var(--space-2);
  padding-block: var(--space-2);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.page-about .about-jump a {
  padding: var(--space-1) var(--space-2);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  text-decoration: none;
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-pill);
  transition: color 160ms ease, border-color 160ms ease;
}

.page-about .about-jump a:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}

/* ---------- 通用区块 ---------- */
.page-about .about-section {
  padding-block: var(--section-y);
  scroll-margin-top: var(--space-8);
}

.page-about .about-section--quiet {
  padding-block: var(--section-y) var(--section-y-lg);
  background: var(--color-surface-alt);
}

.page-about .about-section-head {
  margin-bottom: var(--space-4);
}

.page-about .about-split {
  display: grid;
  gap: var(--space-4);
}

.page-about .about-copy h2 {
  margin: 0 0 var(--space-2);
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

.page-about .about-copy .eyebrow {
  margin: 0 0 var(--space-2);
}

.page-about .about-copy p {
  max-width: var(--measure);
  margin: 0 0 var(--space-2);
  color: var(--color-ink-soft);
  line-height: var(--leading-body);
}

.page-about .num-lead {
  font-family: var(--font-mono);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  font-variant-numeric: tabular-nums;
  color: var(--color-accent);
}

/* ---------- 图片 ---------- */
.page-about .about-media {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-lg);
  background: var(--color-surface-deep);
}

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

.page-about .about-expansion-figure .media-frame-label {
  display: block;
  margin-top: var(--space-1);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

/* ---------- 键值行 ---------- */
.page-about .about-facts {
  list-style: none;
  margin: var(--space-3) 0 0;
  padding: 0;
}

.page-about .about-facts li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-1) var(--space-2);
  padding-block: var(--space-2);
  border-top: var(--border-thin) solid var(--color-line);
  font-size: var(--text-sm);
}

.page-about .about-facts .stat-key {
  color: var(--color-ink-soft);
}

.page-about .about-facts .stat-val {
  font-family: var(--font-mono);
  font-size: var(--text-base);
  font-variant-numeric: tabular-nums;
  color: var(--color-ink);
}

.page-about .about-facts .stat-val--accent {
  color: var(--color-accent);
}

/* ---------- 扩建阶梯 ---------- */
.page-about .about-stair {
  display: grid;
  gap: var(--space-3);
}

.page-about .about-stage {
  position: relative;
  padding: var(--space-3) var(--space-3) var(--space-3) var(--space-4);
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-1);
  transition: border-color 160ms ease, transform 160ms ease;
}

.page-about .about-stage::before {
  content: "";
  position: absolute;
  inset-block: var(--space-2);
  inset-inline-start: calc(var(--border-thin) * 3);
  width: calc(var(--border-thin) * 3);
  border-radius: var(--radius-pill);
  background: linear-gradient(180deg,
    var(--color-accent) 0 var(--stage-scale, 30%),
    var(--color-line) var(--stage-scale, 30%) 100%);
}

.page-about .about-stage:nth-child(1) {
  --stage-scale: 26%;
}

.page-about .about-stage:nth-child(2) {
  --stage-scale: 54%;
}

.page-about .about-stage:nth-child(3) {
  --stage-scale: 88%;
}

.page-about .about-stage:hover {
  border-color: var(--color-primary);
  transform: translateY(-2px);
}

.page-about .about-stage summary {
  position: relative;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: baseline;
  gap: var(--space-1) var(--space-2);
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-stage summary::after {
  content: "展开";
  position: absolute;
  inset-block-start: 0;
  inset-inline-end: 0;
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
}

.page-about .about-stage[open] summary::after {
  content: "收起";
}

.page-about .about-stage-index {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  color: var(--color-primary);
}

.page-about .about-stage-name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
}

.page-about .about-stage-scale {
  grid-column: 1 / -1;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-variant-numeric: tabular-nums;
  color: var(--color-accent);
}

.page-about .about-stage-body {
  margin-top: var(--space-2);
  padding-top: var(--space-2);
  border-top: var(--border-thin) solid var(--color-line);
}

.page-about .about-stage-body p {
  max-width: var(--measure);
  margin: 0 0 var(--space-2);
  color: var(--color-ink-soft);
  line-height: var(--leading-body);
}

.page-about .about-stage-facts {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-stage-facts li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-1) var(--space-2);
  padding-block: var(--space-1);
  border-top: var(--border-thin) solid var(--color-line);
  font-size: var(--text-sm);
}

.page-about .about-stage-facts .stat-key {
  color: var(--color-ink-soft);
}

.page-about .about-stage-facts .stat-val {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  color: var(--color-ink);
}

.page-about .about-stage-facts .stat-val--accent {
  color: var(--color-accent);
}

/* ---------- 深色区块 ---------- */
.page-about .about-dark {
  padding-block: var(--section-y);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  scroll-margin-top: var(--space-8);
}

.page-about .about-dark .about-copy h2 {
  color: var(--color-contrast-ink);
}

.page-about .about-dark .about-copy p {
  color: color-mix(in srgb, var(--color-contrast-ink) 78%, transparent);
}

.page-about .about-dark .num-lead {
  color: var(--color-contrast-accent);
}

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

.page-about .about-dark .about-facts li {
  border-top-color: var(--color-contrast-line);
}

.page-about .about-dark .about-facts .stat-key {
  color: color-mix(in srgb, var(--color-contrast-ink) 66%, transparent);
}

.page-about .about-dark .about-facts .stat-val {
  color: var(--color-contrast-ink);
}

.page-about .about-dark .about-facts .stat-val--accent {
  color: var(--color-contrast-accent);
}

.page-about .about-dark .about-media {
  border-color: var(--color-contrast-line);
}

/* ---------- 原则条目 ---------- */
.page-about .about-principles {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: var(--border-thin) solid var(--color-line);
}

.page-about .about-principle {
  display: grid;
  gap: var(--space-1) var(--space-3);
  padding-block: var(--space-3);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.page-about .about-principle-head {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
}

.page-about .about-principle-index {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  color: var(--color-accent);
}

.page-about .about-principle h3 {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: var(--weight-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

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

.page-about .about-principle-link {
  align-self: start;
  justify-self: start;
  font-size: var(--text-sm);
  color: var(--color-primary);
  text-decoration: none;
  border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 40%, transparent);
  padding-bottom: 2px;
  transition: color 160ms ease, border-color 160ms ease, opacity 160ms ease;
}

.page-about .about-principle-link::after {
  content: " →";
}

.page-about .about-principle-link:hover {
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
}

@media (hover: hover) {
  .page-about .about-principle-link {
    opacity: 0.6;
  }

  .page-about .about-principle:hover .about-principle-link,
  .page-about .about-principle-link:hover,
  .page-about .about-principle-link:focus-visible {
    opacity: 1;
  }
}

/* ---------- 继续查看 ---------- */
.page-about .about-next {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-2);
}

.page-about .about-next-card {
  display: grid;
  gap: var(--space-1);
  padding: var(--space-3);
  text-decoration: none;
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-1);
  transition: border-color 160ms ease, transform 160ms ease, box-shadow 160ms ease;
}

.page-about .about-next-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-2);
}

.page-about .about-next-kicker {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-accent);
}

.page-about .about-next-title {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
}

.page-about .about-next-desc {
  font-size: var(--text-sm);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

/* ---------- 响应式 ---------- */
@media (min-width: 560px) {
  .page-about .about-figures {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: var(--space-3);
  }

  .page-about .about-figure:nth-child(2) {
    padding-block-start: 0;
    border-top: 0;
  }
}

@media (min-width: 700px) {
  .page-about .about-next {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-principle {
    grid-template-columns: minmax(0, 4fr) minmax(0, 6fr);
  }

  .page-about .about-principle-link {
    grid-column: 2;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    padding-block: var(--space-6) var(--space-8);
  }

  .page-about .about-hero-inner {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: end;
    gap: var(--space-6);
    padding-block: var(--space-4) var(--space-4);
  }

  .page-about .about-hero-lead h1 {
    font-size: var(--text-3xl);
  }

  .page-about .about-split {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    gap: var(--space-6);
    align-items: start;
  }

  .page-about .about-split-media {
    grid-column: 1 / 7;
  }

  .page-about .about-split-body {
    grid-column: 7 / 13;
    padding-block-start: var(--space-4);
  }

  .page-about .about-split--reverse .about-split-media {
    grid-column: 7 / 13;
  }

  .page-about .about-split--reverse .about-split-body {
    grid-column: 1 / 7;
    padding-block-start: 0;
  }

  .page-about .about-stair {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    align-items: start;
  }

  .page-about .about-stage:nth-child(1) {
    grid-column: 1 / 6;
  }

  .page-about .about-stage:nth-child(2) {
    grid-column: 4 / 10;
    margin-block-start: var(--space-4);
  }

  .page-about .about-stage:nth-child(3) {
    grid-column: 7 / 13;
    margin-block-start: var(--space-6);
  }
}

@media (min-width: 1040px) {
  .page-about .about-next {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-stage,
  .page-about .about-next-card,
  .page-about .about-jump a,
  .page-about .about-principle-link {
    transition: none;
  }

  .page-about .about-stage:hover,
  .page-about .about-next-card:hover {
    transform: none;
  }
}