.page-about {
  display: block;
}

/* ---------- 面包屑间距 ---------- */
.page-about .breadcrumb {
  padding-block: var(--space-3);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  display: flex;
  align-items: flex-end;
  overflow: hidden;
  min-height: 520px;
  padding-block: var(--space-8);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.page-about .about-hero__media {
  position: absolute;
  inset: 0;
}

.page-about .about-hero__media img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 32%;
  filter: saturate(0.65) contrast(1.04);
}

.page-about .about-hero__media::after {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--overlay-scrim);
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: var(--space-3);
  color: var(--color-contrast-ink);
  max-width: calc(var(--container) - var(--gutter) * 2);
}

.page-about .about-hero__inner .eyebrow {
  color: var(--color-contrast-accent);
}

.page-about .about-hero h1 {
  font-family: var(--font-heading);
  font-size: var(--text-4xl);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-contrast-ink);
  max-width: 22ch;
  margin: 0;
}

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

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-3);
  margin: var(--space-3) 0 0;
  padding-top: var(--space-4);
  border-top: var(--border-thin) solid rgba(53, 51, 56, 0.28);
}

.page-about .fact dt {
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: rgba(53, 51, 56, 0.68);
  margin-bottom: var(--space-1);
}

.page-about .fact dd {
  margin: 0;
  font-size: var(--text-lg);
  color: var(--color-contrast-ink);
}

.page-about .fact .num {
  font-family: var(--font-mono);
  font-size: var(--text-2xl);
  font-weight: var(--weight-heading);
  letter-spacing: 0.03em;
  color: var(--color-contrast-accent);
}

/* ---------- 章节通用 ---------- */
.page-about .about-chapter {
  padding-block: var(--section-y);
}

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

.page-about .about-chapter__mark .section-number {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-3xl);
  line-height: 1;
  letter-spacing: 0.04em;
  color: var(--color-primary);
  opacity: 0.85;
}

.page-about .about-chapter__head {
  margin-bottom: var(--space-6);
}

.page-about .about-chapter__head h2,
.page-about .about-chapter__body h2 {
  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);
  margin: 0 0 var(--space-3);
  max-width: 26ch;
}

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

.page-about .about-body p {
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink);
  margin: 0 0 var(--space-3);
}

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

.page-about .about-body a {
  color: var(--color-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

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

/* ---------- 阶段索引 ---------- */
.page-about .stage-nav {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-6);
}

.page-about .stage-nav__item {
  display: inline-flex;
  align-items: baseline;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-3);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-pill);
  background: var(--color-surface-alt);
  color: var(--color-ink-soft);
  text-decoration: none;
  font-size: var(--text-sm);
  transition: border-color 220ms ease, color 220ms ease, background-color 220ms ease;
}

.page-about .stage-nav__item:hover,
.page-about .stage-nav__item:focus-visible {
  border-color: var(--color-accent);
  color: var(--color-ink);
  background: color-mix(in srgb, var(--color-accent) 10%, var(--color-surface-alt));
}

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

/* ---------- 阶段段落 ---------- */
.page-about .stages {
  display: grid;
}

.page-about .stage {
  display: grid;
  gap: var(--space-2);
  padding-block: var(--space-6);
  border-top: var(--border-thin) solid var(--color-line);
}

.page-about .stage:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .stage__num .section-number {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  line-height: 0.88;
  letter-spacing: 0.01em;
  color: var(--color-primary);
  opacity: 0.9;
  transition: color 200ms ease, opacity 200ms ease;
}

.page-about .stage:hover .stage__num .section-number {
  color: var(--color-accent);
  opacity: 1;
}

.page-about .stage__title {
  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);
  margin: 0 0 var(--space-2);
  max-width: 24ch;
}

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

/* ---------- 整理原则（浅色对比带） ---------- */
.page-about .about-rules {
  padding-block: var(--section-y);
}

.page-about .about-rules__head {
  margin-bottom: var(--space-6);
}

.page-about .about-rules__head h2 {
  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-contrast-ink);
  margin: 0 0 var(--space-3);
  max-width: 24ch;
}

.page-about .about-rules__intro {
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-contrast-ink);
  opacity: 0.78;
  margin: 0;
}

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

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

.page-about .rule {
  position: relative;
  padding: var(--space-4) var(--space-4) var(--space-4) var(--space-6);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-contrast-accent) 26%, transparent);
  border-radius: var(--radius-md);
  background: color-mix(in srgb, var(--color-contrast-accent) 5%, transparent);
  transition: border-color 240ms ease, box-shadow 240ms ease;
}

.page-about .rule::before {
  content: "";
  position: absolute;
  left: 0;
  top: var(--space-4);
  bottom: var(--space-4);
  width: 2px;
  border-radius: var(--radius-pill);
  background: var(--color-contrast-accent);
}

.page-about .rule:hover,
.page-about .rule:focus-within {
  border-color: var(--color-contrast-accent);
  box-shadow: 0 0 22px color-mix(in srgb, var(--color-contrast-accent) 24%, transparent);
}

.page-about .rule__n {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.1em;
  color: var(--color-contrast-accent);
  margin: 0 0 var(--space-1);
}

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

.page-about .rule__d {
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-contrast-ink);
  opacity: 0.82;
  margin: 0 0 var(--space-3);
}

.page-about .rule__sample {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-2);
  margin: 0;
  padding-top: var(--space-3);
  border-top: var(--border-thin) solid var(--color-contrast-line);
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-contrast-ink);
  opacity: 0.62;
  transition: opacity 240ms ease;
}

.page-about .rule:hover .rule__sample,
.page-about .rule:focus-within .rule__sample {
  opacity: 1;
}

.page-about .rule__sample .tag {
  color: var(--color-contrast-accent);
  border-color: color-mix(in srgb, var(--color-contrast-accent) 42%, transparent);
  background: transparent;
}

.page-about .about-rules__figure {
  margin: 0;
}

.page-about .about-rules__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border-radius: var(--radius-md);
  border: var(--border-thin) solid var(--color-contrast-line);
}

.page-about .about-rules__figure figcaption {
  margin-top: var(--space-2);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-contrast-ink);
  opacity: 0.6;
}

/* ---------- 团队分工 ---------- */
.page-about .team-grid {
  display: grid;
  gap: var(--space-4);
}

.page-about .team-card {
  padding: var(--space-4);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-lg);
  background: var(--color-surface-alt);
  transition: border-color 240ms ease, box-shadow 240ms ease;
}

.page-about .team-card:hover {
  border-color: color-mix(in srgb, var(--color-accent) 60%, var(--color-line));
  box-shadow: var(--shadow-1);
}

.page-about .team-card__role {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-primary);
  margin: 0 0 var(--space-2);
  padding-bottom: var(--space-2);
  border-bottom: var(--border-thin) solid var(--color-line);
}

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

.page-about .team-card__desc {
  font-size: var(--text-sm);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
  margin: 0;
}

.page-about .team-strip {
  margin: var(--space-6) 0 0;
}

.page-about .team-strip img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 12 / 5;
  object-fit: cover;
  border-radius: var(--radius-lg);
  border: var(--border-thin) solid var(--color-line);
}

.page-about .team-strip figcaption {
  margin-top: var(--space-2);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}

/* ---------- 合规与联系 ---------- */
.page-about .about-legal {
  border-top: var(--border-thin) solid var(--color-line);
}

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

.page-about .contact-facts {
  margin: var(--space-6) 0 0;
  display: grid;
  gap: 0;
  border-top: var(--border-thin) solid var(--color-line);
}

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

.page-about .contact-facts__row dt {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  color: var(--color-ink-muted);
}

.page-about .contact-facts__row dd {
  margin: 0;
  font-size: var(--text-base);
  color: var(--color-ink);
  word-break: break-word;
}

.page-about .contact-facts__row dd a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .contact-facts__row dd a:hover,
.page-about .contact-facts__row dd a:focus-visible {
  color: var(--color-focus);
}

.page-about .about-legal__aside {
  padding: var(--space-4);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-lg);
  background: var(--color-surface-alt);
  align-self: start;
}

.page-about .about-legal__aside-title {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
  margin: 0 0 var(--space-3);
  padding-bottom: var(--space-2);
  border-bottom: var(--border-thin) solid var(--color-line);
}

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

.page-about .about-legal__links a {
  display: block;
  padding: var(--space-2) var(--space-3);
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
  line-height: 1.55;
  color: var(--color-ink-soft);
  text-decoration: none;
  transition: border-color 220ms ease, color 220ms ease, background-color 220ms ease;
}

.page-about .about-legal__links a:hover,
.page-about .about-legal__links a:focus-visible {
  border-color: var(--color-accent);
  color: var(--color-ink);
  background: color-mix(in srgb, var(--color-accent) 8%, transparent);
}

/* ---------- 响应式 ---------- */
@media (min-width: 700px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-chapter__grid {
    grid-template-columns: minmax(96px, 1fr) minmax(0, 4fr);
    gap: var(--space-8);
  }

  .page-about .about-chapter__mark .section-number {
    font-size: var(--text-4xl);
    position: sticky;
    top: var(--space-8);
  }

  .page-about .contact-facts__row {
    grid-template-columns: minmax(0, 180px) minmax(0, 1fr);
    align-items: baseline;
    gap: var(--space-3);
  }
}

@media (min-width: 860px) {
  .page-about .about-hero {
    min-height: 640px;
  }

  .page-about .stage {
    grid-template-columns: minmax(110px, 1fr) minmax(0, 2.8fr);
    gap: var(--space-8);
    padding-block: var(--space-8);
  }

  .page-about .about-rules__layout {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
    gap: var(--space-8);
    align-items: start;
  }

  .page-about .team-grid {
    grid-template-columns: 1.4fr 1fr 1.15fr;
    gap: var(--space-6);
    align-items: start;
  }

  .page-about .team-card:nth-child(2) {
    margin-top: var(--space-8);
  }

  .page-about .team-card:nth-child(3) {
    margin-top: calc(var(--space-8) * 1.7);
  }

  .page-about .about-legal__grid {
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
    gap: var(--space-8);
  }
}

@media (min-width: 1100px) {
  .page-about .about-hero h1 {
    font-size: var(--text-4xl);
  }

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

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

@media (prefers-reduced-motion: reduce) {
  .page-about .stage-nav__item,
  .page-about .rule,
  .page-about .team-card,
  .page-about .about-legal__links a,
  .page-about .stage__num .section-number {
    transition: none;
  }
}
</main>