.page-about {
  --about-side: 172px;
  --about-gap: var(--space-8);
  background: var(--color-surface);
  color: var(--color-ink);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  background: var(--color-surface-deep);
  border-bottom: var(--border-thin) solid var(--color-line);
  padding: calc(var(--space-6) + var(--space-3)) 0 var(--space-8);
}

@media (min-width: 960px) {
  .page-about .about-hero {
    padding: calc(var(--space-8) * 1.5) 0 var(--space-8);
  }
}

.page-about .about-hero-media {
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

.page-about .about-hero-media img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 28%;
  opacity: 0.52;
}

.page-about .about-hero-media::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg,
      color-mix(in srgb, var(--color-surface) 50%, transparent) 0%,
      color-mix(in srgb, var(--color-surface) 86%, transparent) 58%,
      var(--color-surface) 100%);
}

.page-about .about-hero-inner {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.page-about .about-hero-inner .breadcrumb {
  margin-bottom: var(--space-1);
}

.page-about .about-kicker {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: var(--color-primary);
}

.page-about .about-hero h1 {
  margin: 0;
  max-width: 20ch;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-3xl);
  line-height: var(--leading-heading);
  letter-spacing: 0.035em;
  color: var(--color-ink);
}

@media (min-width: 960px) {
  .page-about .about-hero h1 {
    font-size: var(--text-4xl);
  }
}

.page-about .about-hero-lede {
  margin: 0;
  max-width: var(--measure);
  font-family: var(--font-serif, var(--font-body));
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

/* ---------- 长文画布 ---------- */
.page-about .about-canvas {
  background: var(--color-surface);
  padding: var(--space-8) 0 var(--section-y-lg);
}

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

@media (min-width: 960px) {
  .page-about .about-canvas-inner {
    grid-template-columns: var(--about-side) minmax(0, 1fr);
    gap: var(--about-gap);
  }
}

/* 侧栏小节索引 */
.page-about .about-toc {
  display: none;
}

@media (min-width: 960px) {
  .page-about .about-toc {
    display: block;
    position: sticky;
    top: calc(var(--space-8) * 1.4);
    align-self: start;
  }
}

.page-about .about-toc-title {
  margin: 0 0 var(--space-2);
  padding-bottom: var(--space-2);
  border-bottom: var(--border-thin) solid var(--color-line);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

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

.page-about .toc a {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  padding: 6px var(--space-2);
  margin-left: -2px;
  border-left: var(--border-thick) solid transparent;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  text-decoration: none;
  transition: color 180ms linear, border-color 180ms linear;
}

.page-about .toc a:hover {
  color: var(--color-ink);
}

.page-about .toc a[data-current] {
  color: var(--color-primary);
  border-left-color: var(--color-primary);
  font-weight: var(--weight-heading);
}

.page-about .toc-no {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}

.page-about .toc a[data-current] .toc-no {
  color: var(--color-primary);
}

/* 叙事流 */
.page-about .about-stream {
  display: flex;
  flex-direction: column;
  gap: calc(var(--space-8) + var(--space-1));
  min-width: 0;
}

.page-about .about-block {
  max-width: var(--measure);
}

.page-about .about-block p {
  margin: 0 0 var(--space-3);
  font-family: var(--font-serif, var(--font-body));
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

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

.page-about .about-block a {
  color: var(--color-primary);
  text-decoration: none;
  border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 45%, transparent);
  transition: border-color 180ms linear, color 180ms linear;
}

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

.page-about .about-lede::first-letter {
  float: left;
  padding: 0.06em 0.14em 0 0;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xl);
  line-height: 1;
  color: var(--color-primary);
}

/* 区块头：竖排标注 + 编号 + 标题 */
.page-about .about-block-head {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
  padding-top: var(--space-3);
  border-top: var(--border-thin) solid var(--color-line);
}

.page-about .about-note {
  flex: 0 0 auto;
  writing-mode: vertical-rl;
  text-orientation: upright;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.2em;
  color: var(--color-ink-muted);
}

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

.page-about .about-block-no {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.2em;
  color: var(--color-primary);
}

.page-about .about-block h2 {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xl);
  line-height: 1.2;
  letter-spacing: 0.025em;
  color: var(--color-ink);
}

@media (min-width: 720px) {
  .page-about .about-block h2 {
    font-size: var(--text-2xl);
  }
}

/* 维护方式配图 */
.page-about .about-media {
  margin: 0 0 var(--space-4);
  overflow: hidden;
  border-radius: var(--radius-sm);
  background: var(--color-surface-alt);
}

.page-about .about-media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  opacity: 0.92;
}

/* 折叠面板 */
.page-about .about-panels {
  display: flex;
  flex-direction: column;
  margin-top: var(--space-3);
  border-top: var(--border-thin) solid var(--color-line);
}

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

.page-about .panel-trigger {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  width: 100%;
  padding: var(--space-3) 0;
  background: none;
  border: 0;
  cursor: pointer;
  text-align: left;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  letter-spacing: 0.02em;
  color: var(--color-ink);
}

.page-about .panel-trigger .panel-state {
  margin-left: auto;
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
}

.page-about .panel-trigger .panel-state::before {
  content: "＋ ";
  color: var(--color-primary);
}

.page-about .panel[data-open] .panel-trigger .panel-state::before {
  content: "− ";
}

.page-about .panel:not([data-open]) .panel-body {
  display: none;
}

.page-about .panel-body {
  padding-bottom: var(--space-4);
}

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

/* 数字带 */
.page-about .about-metrics {
  position: relative;
  padding: var(--space-6) 0;
  border-top: var(--border-thin) solid var(--color-line);
  border-bottom: var(--border-thin) solid var(--color-line);
  background: var(--color-surface-alt);
  overflow: hidden;
}

.page-about .about-metrics::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: repeating-linear-gradient(
    135deg,
    color-mix(in srgb, var(--color-highlight) 45%, transparent) 0 1px,
    transparent 1px 13px
  );
  opacity: 0.6;
  pointer-events: none;
}

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

.page-about .about-metrics-inner {
  position: relative;
  padding: 0 var(--space-3);
}

@media (min-width: 720px) {
  .page-about .about-metrics-inner {
    padding: 0 var(--space-4);
  }
}

.page-about .about-metrics-label {
  margin: 0 0 var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.page-about .about-metrics-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-3);
  margin: 0;
}

@media (min-width: 720px) {
  .page-about .about-metrics-list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: var(--space-4);
  }
}

.page-about .about-metric {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 6px;
  padding-top: var(--space-2);
  border-top: var(--border-thin) solid var(--color-ink-muted);
}

.page-about .about-metric dt {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
}

.page-about .about-metric dd {
  margin: 0;
  font-family: var(--font-mono);
  font-weight: var(--weight-heading);
  font-size: var(--text-xl);
  line-height: 1;
  color: var(--color-ink);
}

@media (min-width: 720px) {
  .page-about .about-metric dd {
    font-size: var(--text-2xl);
  }
}

/* 地域与备案区块 */
.page-about .about-block--region {
  position: relative;
  isolation: isolate;
  max-width: none;
  overflow: hidden;
  padding: var(--space-6) var(--space-4) var(--space-6);
  border-top: var(--border-thin) solid var(--color-line);
  border-bottom: var(--border-thin) solid var(--color-line);
  background: var(--color-surface-alt);
}

@media (min-width: 960px) {
  .page-about .about-block--region {
    padding: var(--space-6) var(--space-6);
  }
}

.page-about .about-region-media {
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

.page-about .about-region-media img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.22;
}

.page-about .about-region-media::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(
    90deg,
    color-mix(in srgb, var(--color-surface-alt) 92%, transparent) 0%,
    color-mix(in srgb, var(--color-surface-alt) 72%, transparent) 100%
  );
}

.page-about .about-region-inner {
  position: relative;
  z-index: 1;
  max-width: var(--measure);
}

.page-about .about-region-inner p {
  margin: 0 0 var(--space-3);
  font-family: var(--font-serif, var(--font-body));
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

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

.page-about .about-region-inner a {
  color: var(--color-primary);
  text-decoration: none;
  border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 45%, transparent);
}

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

/* 减少动效 */
@media (prefers-reduced-motion: reduce) {
  .page-about .toc a {
    transition: none;
  }
}
</main>