.page-about {
  background: var(--ink-900);
  color: var(--paper);
  --about-gap: clamp(20px, 4vw, 56px);
}

.page-about a:focus-visible {
  outline: 2px solid var(--mint);
  outline-offset: 3px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding-block: var(--s5) var(--s6);
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(120% 90% at 88% 0%, rgba(57, 245, 176, 0.10), transparent 62%),
    repeating-linear-gradient(90deg, var(--line-soft) 0 1px, transparent 1px 120px),
    var(--ink-900);
}

.page-about .about-hero__inner {
  display: grid;
  gap: var(--s5);
  align-items: center;
}

.page-about .breadcrumbs__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0 0 var(--s4);
  padding: 0;
  list-style: none;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.page-about .breadcrumbs__link {
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.12s var(--ease), border-color 0.12s var(--ease);
}

.page-about .breadcrumbs__link:hover,
.page-about .breadcrumbs__link:focus-visible {
  color: var(--mint);
  border-bottom-color: var(--mint);
}

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

.page-about .about-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 var(--s3);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mint);
}

.page-about .about-eyebrow::before {
  content: "";
  width: 26px;
  height: 2px;
  background: var(--acid);
}

.page-about .about-hero__title {
  margin: 0 0 var(--s3);
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(32px, 8vw, 70px);
  line-height: 1;
  letter-spacing: -0.03em;
}

.page-about .about-hero__lede {
  max-width: 46ch;
  margin: 0 0 var(--s4);
  font-size: clamp(15px, 2.1vw, 18px);
  line-height: 1.75;
  color: var(--paper);
  opacity: 0.9;
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-stat {
  background: var(--ink-900);
  padding: var(--s3) var(--s2);
  min-width: 0;
}

.page-about .about-stat__num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(24px, 4.4vw, 34px);
  line-height: 1;
  color: var(--mint);
}

.page-about .about-stat__label {
  display: block;
  margin-top: 8px;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.page-about .about-hero__figure {
  margin: 0;
  border: 1px solid var(--line);
  background: var(--ink-800);
}

.page-about .about-hero__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 7 / 4;
  object-fit: cover;
}

.page-about .about-figure__cap {
  display: block;
  padding: 10px var(--s2);
  border-top: 1px solid var(--line);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--muted);
}

/* ---------- 主体分栏 ---------- */
.page-about .about-body {
  padding-block: var(--s6) var(--s7);
}

.page-about .about-layout {
  display: grid;
  gap: var(--s5);
}

.page-about .about-layout__aside,
.page-about .about-layout__main {
  min-width: 0;
}

.page-about .about-index__head {
  margin: 0;
  padding-bottom: var(--s2);
  border-bottom: 1px solid var(--line);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--muted);
}

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

.page-about .about-index__link {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 11px 0 11px 10px;
  border-bottom: 1px solid var(--line-soft);
  box-shadow: inset 0 0 0 0 var(--mint);
  color: var(--muted);
  font-size: 14px;
  text-decoration: none;
  transition: color 0.12s var(--ease), box-shadow 0.12s var(--ease);
}

.page-about .about-index__num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--line);
  transition: color 0.12s var(--ease);
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible,
.page-about .about-index__link.is-active {
  color: var(--mint);
  box-shadow: inset 2px 0 0 var(--mint);
}

.page-about .about-index__link:hover .about-index__num,
.page-about .about-index__link:focus-visible .about-index__num,
.page-about .about-index__link.is-active .about-index__num {
  color: var(--acid);
}

/* ---------- 章节 ---------- */
.page-about .about-sec {
  padding-block: var(--s5);
  border-top: 1px solid var(--line);
  scroll-margin-top: calc(var(--header-h) + 24px);
}

.page-about .about-layout__main > .about-sec:first-child {
  padding-top: 0;
  border-top: 0;
}

.page-about .about-sec__head {
  display: grid;
  gap: 6px;
  margin-bottom: var(--s3);
}

.page-about .about-sec__num {
  font-family: var(--font-mono);
  font-size: clamp(26px, 5vw, 42px);
  line-height: 1;
  color: var(--mint);
  opacity: 0.45;
}

.page-about .about-sec__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(22px, 3.8vw, 34px);
  line-height: 1.14;
  letter-spacing: -0.02em;
}

.page-about .about-sec p {
  max-width: 66ch;
  margin: 0 0 var(--s2);
  line-height: 1.75;
}

.page-about .about-sec__note {
  font-size: 14px;
  color: var(--muted);
}

.page-about .about-groups {
  list-style: none;
  display: grid;
  gap: 1px;
  margin: var(--s3) 0 0;
  padding: 0;
  background: var(--line);
  border-block: 1px solid var(--line);
}

.page-about .about-groups__item {
  background: var(--ink-900);
  padding: var(--s3) var(--s2) var(--s3) var(--s2);
  border-left: 2px solid var(--line);
  min-width: 0;
  transition: border-color 0.12s var(--ease), background-color 0.12s var(--ease);
}

.page-about .about-groups__item:hover {
  border-left-color: var(--mint);
  background: var(--ink-800);
}

.page-about .about-groups__name {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.page-about .about-groups__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .about-figure {
  margin: var(--s4) 0 0;
  border: 1px solid var(--line);
  background: var(--ink-800);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 8 / 5;
  object-fit: cover;
}

/* ---------- 四步流程 ---------- */
.page-about .about-flow {
  list-style: none;
  counter-reset: flow;
  display: grid;
  gap: var(--s3);
  margin: var(--s4) 0 0;
  padding: 0;
}

.page-about .about-flow__item {
  counter-increment: flow;
  padding-top: var(--s2);
  border-top: 2px solid var(--line);
  transition: border-color 0.12s var(--ease);
}

.page-about .about-flow__item:hover {
  border-top-color: var(--acid);
}

.page-about .about-flow__item::before {
  content: "0" counter(flow);
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 22px;
  line-height: 1;
  color: var(--acid);
}

.page-about .about-flow__title {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 700;
}

.page-about .about-flow__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
}

/* ---------- 覆盖规模 ---------- */
.page-about .about-cover {
  display: grid;
  gap: var(--s4);
  margin-top: var(--s4);
}

.page-about .about-cover__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--s3);
}

.page-about .about-cover__stat {
  padding-top: 12px;
  border-top: 1px solid var(--line);
  min-width: 0;
}

.page-about .about-cover__num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(26px, 4.6vw, 38px);
  line-height: 1;
  color: var(--paper);
}

.page-about .about-cover__label {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.page-about .about-cover .about-figure {
  margin: 0;
}

.page-about .about-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding-bottom: 2px;
  font-size: 14px;
  letter-spacing: 0.04em;
  color: var(--mint);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.12s var(--ease), color 0.12s var(--ease);
}

.page-about .about-link:hover,
.page-about .about-link:focus-visible {
  color: var(--acid);
  border-bottom-color: var(--acid);
}

/* ---------- 人群 ---------- */
.page-about .about-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: var(--s3) 0 var(--s4);
}

.page-about .about-chip {
  display: inline-block;
  padding: 8px 14px;
  border: 1px solid var(--line);
  background: var(--ink-800);
  color: var(--muted);
  font-size: 13px;
  letter-spacing: 0.05em;
  text-decoration: none;
  transition: color 0.12s var(--ease), border-color 0.12s var(--ease), background-color 0.12s var(--ease);
}

.page-about .about-chip:hover,
.page-about .about-chip:focus-visible {
  color: var(--paper);
  border-color: var(--acid);
  background: var(--ink-700);
}

.page-about .about-scenes {
  display: grid;
  gap: var(--s3);
}

.page-about .about-scene {
  padding-top: var(--s2);
  border-top: 1px solid var(--line);
  scroll-margin-top: calc(var(--header-h) + 24px);
  min-width: 0;
}

.page-about .about-scene__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.page-about .about-scene p {
  margin: 6px 0 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
  max-width: 40ch;
}

/* ---------- 发展时间线 ---------- */
.page-about .about-timeline {
  list-style: none;
  display: grid;
  gap: var(--s4);
  margin: var(--s4) 0 0;
  padding: 0 0 0 var(--s3);
  border-left: 1px solid var(--line);
}

.page-about .about-stage {
  position: relative;
  min-width: 0;
}

.page-about .about-stage::before {
  content: "";
  position: absolute;
  left: calc(-1 * var(--s3) - 5px);
  top: 5px;
  width: 9px;
  height: 9px;
  border: 2px solid var(--mint);
  border-radius: 50%;
  background: var(--ink-900);
  transition: transform 0.18s var(--ease), background-color 0.18s var(--ease);
}

.page-about .about-stage:hover::before,
.page-about .about-stage:focus-within::before {
  transform: scale(1.4);
  background: var(--mint);
}

.page-about .about-stage__phase {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--acid);
}

.page-about .about-stage__title {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.page-about .about-stage__text {
  margin: 0;
  max-width: 30ch;
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .about-top {
  display: inline-block;
  margin-top: var(--s4);
  font-size: 13px;
  letter-spacing: 0.05em;
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  transition: color 0.12s var(--ease), border-color 0.12s var(--ease);
}

.page-about .about-top:hover,
.page-about .about-top:focus-visible {
  color: var(--mint);
  border-bottom-color: var(--mint);
}

/* ---------- 收束 ---------- */
.page-about .about-cta {
  margin-top: var(--s6);
  padding: var(--s4) var(--s3);
  border: 1px solid var(--line);
  background: linear-gradient(135deg, var(--ink-700), var(--ink-900) 72%);
}

.page-about .about-cta__title {
  margin: 0 0 var(--s2);
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(22px, 3.6vw, 30px);
  letter-spacing: -0.02em;
}

.page-about .about-cta__text {
  max-width: 58ch;
  margin: 0 0 var(--s3);
  font-size: 15px;
  line-height: 1.75;
  color: var(--paper);
  opacity: 0.9;
}

.page-about .about-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-scenes {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--s3) var(--s4);
  }

  .page-about .about-cta {
    padding: var(--s5) var(--s4);
  }
}

@media (min-width: 760px) {
  .page-about .about-groups {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

@media (min-width: 900px) {
  .page-about .about-flow {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: var(--s3);
  }

  .page-about .about-timeline {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: var(--s3);
    padding: var(--s4) 0 0;
    border-left: 0;
    border-top: 1px solid var(--line);
  }

  .page-about .about-stage::before {
    left: 0;
    top: calc(-1 * var(--s4) - 5px);
  }
}

@media (min-width: 960px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    gap: var(--s6);
  }

  .page-about .about-hero__figure img {
    aspect-ratio: 7 / 5;
  }
}

@media (min-width: 1024px) {
  .page-about .about-layout {
    grid-template-columns: minmax(180px, 216px) minmax(0, 1fr);
    gap: var(--s6);
    align-items: start;
  }

  .page-about .about-layout__aside {
    position: sticky;
    top: calc(var(--header-h) + 24px);
  }

  .page-about .about-index__link {
    font-size: 13px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-stage::before,
  .page-about .about-groups__item,
  .page-about .about-flow__item,
  .page-about .about-chip,
  .page-about .about-index__link {
    transition: none;
  }

  .page-about .about-stage:hover::before,
  .page-about .about-stage:focus-within::before {
    transform: none;
  }
}