.page-about {
  --ab-rail: 200px;
  --ab-cream-ink: #23443A;
  background: var(--c-ink);
  color: var(--c-cream);
  font-family: var(--font-body);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  padding: clamp(18px, 3vw, 34px) 0 clamp(44px, 6vw, 88px);
  background:
    radial-gradient(115% 85% at 84% 6%, rgba(55, 242, 198, 0.16), transparent 60%),
    linear-gradient(180deg, var(--c-ink) 0%, #071b15 100%);
  border-bottom: 1px solid var(--c-line);
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    repeating-linear-gradient(0deg, rgba(42, 54, 52, 0.35) 0 1px, transparent 1px 80px),
    repeating-linear-gradient(90deg, rgba(42, 54, 52, 0.28) 0 1px, transparent 1px 80px);
  pointer-events: none;
  opacity: 0.5;
}

.page-about .ab-hero > .container {
  position: relative;
  z-index: 1;
}

.page-about .breadcrumb {
  margin-bottom: clamp(20px, 4vw, 44px);
}

.page-about .breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
}

.page-about .breadcrumb-item {
  color: var(--c-mist);
}

.page-about .breadcrumb-item + .breadcrumb-item::before {
  content: "/";
  margin-right: 8px;
  color: var(--c-line);
}

.page-about .breadcrumb-item a {
  color: var(--c-mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

.page-about .breadcrumb-item a:hover,
.page-about .breadcrumb-item a:focus-visible {
  color: var(--c-cyan);
  border-bottom-color: var(--c-cyan);
}

.page-about .ab-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 5vw, 56px);
  align-items: center;
}

.page-about .ab-kicker {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--c-cyan);
}

.page-about h1 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(34px, 6.4vw, 68px);
  line-height: 1.08;
  letter-spacing: 0.01em;
  color: var(--c-cream);
}

.page-about .ab-lede {
  margin: clamp(18px, 2.4vw, 26px) 0 0;
  max-width: 36em;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.9;
  color: rgba(245, 242, 234, 0.78);
}

.page-about .ab-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(22px, 3vw, 34px);
}

.page-about .ab-hero-visual {
  order: -1;
}

.page-about .ab-hero-svg {
  display: block;
  width: 100%;
  max-width: 460px;
  height: auto;
  margin: 0 auto;
}

.page-about .ab-hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px 12px;
  margin: clamp(34px, 5vw, 64px) 0 0;
  padding-top: clamp(20px, 3vw, 30px);
  border-top: 1px solid var(--c-line);
}

.page-about .ab-stat {
  display: flex;
  flex-direction: column-reverse;
  gap: 8px;
  min-width: 0;
}

.page-about .ab-stat-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--c-mist);
}

.page-about .ab-stat-num {
  margin: 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(22px, 3.2vw, 34px);
  line-height: 1;
  color: var(--c-cyan);
}

/* ---------- 章节骨架 ---------- */
.page-about .ab-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
}

.page-about .ab-index {
  position: sticky;
  top: var(--header-h);
  z-index: 4;
  margin-bottom: 6px;
  padding: 8px 0;
  background: rgba(10, 42, 32, 0.94);
  border-bottom: 1px solid var(--c-line);
}

.page-about .ab-index-title {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  margin: 0;
}

.page-about .ab-index-list {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .ab-index-list::-webkit-scrollbar {
  display: none;
}

.page-about .ab-index-list a {
  display: block;
  white-space: nowrap;
  padding: 8px 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--c-mist);
  text-decoration: none;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  transition: color 160ms var(--ease), border-color 160ms var(--ease), background-color 160ms var(--ease);
}

.page-about .ab-index-list a:hover,
.page-about .ab-index-list a:focus-visible {
  color: var(--c-cyan);
  border-color: var(--c-cyan);
  background: rgba(55, 242, 198, 0.08);
}

.page-about .ab-section {
  padding: clamp(46px, 7vw, 92px) 0;
  border-top: 1px solid var(--c-line);
}

.page-about .ab-section:first-child {
  border-top: 0;
}

.page-about .index-band {
  display: flex;
  align-items: center;
  gap: 12px;
}

.page-about .band-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 34px;
  padding: 4px 8px;
  background: var(--c-deep);
  color: var(--c-cream);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
}

.page-about .band-label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--c-mist);
}

.page-about .section-title {
  margin: 18px 0 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(25px, 3.4vw, 42px);
  line-height: 1.16;
  color: var(--c-cream);
  max-width: 26em;
}

.page-about .ab-assert {
  margin: 18px 0 0;
  max-width: 40em;
  font-size: clamp(15px, 1.7vw, 18px);
  line-height: 1.85;
  color: var(--c-cyan);
}

.page-about .ab-p {
  margin: 16px 0 0;
  max-width: 38em;
  font-size: 15px;
  line-height: 1.9;
  color: rgba(245, 242, 234, 0.76);
}

.page-about .ab-footnote {
  margin: 18px 0 0;
  max-width: 42em;
  font-size: 13px;
  line-height: 1.8;
  color: var(--c-mist);
}

.page-about .ab-link {
  color: var(--c-cream);
  text-decoration: none;
  border-bottom: 1px solid var(--c-teal);
  transition: color 160ms var(--ease), border-color 160ms var(--ease);
}

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

.page-about .ab-cols {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 44px);
}

/* ---------- 通用图片 ---------- */
.page-about .ab-media {
  margin: clamp(26px, 4vw, 42px) 0 0;
}

.page-about .ab-media img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
}

.page-about .ab-media-cap {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--c-mist);
}

/* ---------- 阶梯 ---------- */
.page-about .ab-ladder {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: 62px;
  gap: 10px;
  align-items: end;
  margin-top: clamp(26px, 4vw, 40px);
  padding-bottom: 14px;
  border-bottom: 1px solid var(--c-line);
  overflow-x: auto;
}

.page-about .ab-step {
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  min-height: 300px;
  text-align: center;
}

.page-about .ab-step-bar {
  display: block;
  width: 100%;
  height: 64px;
  background: linear-gradient(180deg, rgba(55, 242, 198, 0.85) 0%, rgba(23, 164, 139, 0.12) 100%);
  border-top: 1px solid var(--c-cyan);
  transition: transform 200ms var(--ease), box-shadow 200ms var(--ease);
}

.page-about .ab-step:hover .ab-step-bar {
  transform: translateY(-4px);
  box-shadow: 0 0 0 1px var(--c-cyan), 0 10px 26px rgba(55, 242, 198, 0.22);
}

.page-about .ab-step:nth-child(1) .ab-step-bar { height: 64px; }
.page-about .ab-step:nth-child(2) .ab-step-bar { height: 100px; }
.page-about .ab-step:nth-child(3) .ab-step-bar { height: 138px; }
.page-about .ab-step:nth-child(4) .ab-step-bar { height: 178px; }
.page-about .ab-step:nth-child(5) .ab-step-bar { height: 220px; }
.page-about .ab-step:nth-child(6) .ab-step-bar { height: 262px; }

.page-about .ab-step-name {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--c-cream);
}

.page-about .ab-step-meta {
  margin-top: 4px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--c-mist);
}

/* ---------- 数据表 ---------- */
.page-about .ab-table-wrap {
  margin-top: clamp(30px, 4vw, 46px);
  overflow-x: auto;
  border: 1px solid var(--c-line);
  background: rgba(11, 15, 14, 0.6);
}

.page-about .ab-table {
  width: 100%;
  min-width: 640px;
  border-collapse: collapse;
  font-size: 14px;
}

.page-about .ab-table-cap {
  padding: 14px 16px 0;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--c-mist);
}

.page-about .ab-table th,
.page-about .ab-table td {
  padding: 13px 16px;
  text-align: left;
  border-bottom: 1px solid var(--c-line);
  vertical-align: middle;
}

.page-about .ab-table thead th {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 400;
  letter-spacing: 0.14em;
  color: var(--c-mist);
  background: rgba(15, 84, 72, 0.22);
}

.page-about .ab-table tbody th {
  font-weight: 500;
  color: var(--c-cream);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
}

.page-about .ab-table tbody td {
  color: rgba(245, 242, 234, 0.8);
}

.page-about .ab-table tbody tr:nth-child(odd) {
  background: rgba(42, 54, 52, 0.14);
}

.page-about .ab-table tbody tr:hover {
  background: rgba(55, 242, 198, 0.08);
}

.page-about .ab-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  color: var(--c-cyan);
}

/* ---------- 角色 ---------- */
.page-about .ab-roles {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: clamp(26px, 4vw, 40px);
}

.page-about .ab-role {
  padding: 24px 22px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(11, 15, 14, 0.9) 0%, rgba(10, 42, 32, 0.35) 100%);
  transition: transform 200ms var(--ease), border-color 200ms var(--ease), box-shadow 200ms var(--ease);
}

.page-about .ab-role:hover,
.page-about .ab-role:focus-within {
  transform: translateY(-4px);
  border-color: var(--c-cyan);
  box-shadow: 0 14px 32px rgba(0, 0, 0, 0.35);
}

.page-about .ab-role-num {
  margin: 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 34px;
  line-height: 1;
  color: var(--c-cyan);
}

.page-about .ab-role-name {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 18px;
  letter-spacing: 0.04em;
  color: var(--c-cream);
}

.page-about .ab-role-desc {
  margin: 10px 0 0;
  font-size: 13.5px;
  line-height: 1.85;
  color: rgba(245, 242, 234, 0.72);
}

/* ---------- 核定流程 ---------- */
.page-about .ab-review {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 48px);
  margin-top: clamp(26px, 4vw, 40px);
}

.page-about .ab-steps {
  position: relative;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-steps::before {
  content: "";
  position: absolute;
  left: 9px;
  top: 8px;
  bottom: 12px;
  width: 1px;
  background: var(--c-line);
}

.page-about .ab-step-item {
  position: relative;
  padding: 0 0 28px 36px;
}

.page-about .ab-step-item:last-child {
  padding-bottom: 0;
}

.page-about .ab-step-dot {
  position: absolute;
  left: 0;
  top: 3px;
  width: 19px;
  height: 19px;
  border-radius: 50%;
  border: 1px solid var(--c-cyan);
  background: var(--c-ink);
}

.page-about .ab-step-dot::after {
  content: "";
  position: absolute;
  inset: 5px;
  border-radius: 50%;
  background: var(--c-cyan);
}

.page-about .ab-step-time {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--c-amber);
}

.page-about .ab-step-title {
  margin: 8px 0 0;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 17px;
  letter-spacing: 0.03em;
  color: var(--c-cream);
}

.page-about .ab-step-text {
  margin: 8px 0 0;
  max-width: 34em;
  font-size: 14px;
  line-height: 1.85;
  color: rgba(245, 242, 234, 0.74);
}

.page-about .ab-review .ab-media {
  margin-top: 0;
}

.page-about .note {
  margin-top: clamp(26px, 4vw, 40px);
  padding: 14px 18px;
  border-left: 2px solid var(--c-amber);
  background: rgba(242, 169, 59, 0.08);
  font-size: 13.5px;
  line-height: 1.8;
  color: rgba(245, 242, 234, 0.82);
}

/* ---------- 合作生态（暖白反色区） ---------- */
.page-about .ab-section--band {
  padding-left: clamp(20px, 3vw, 40px);
  padding-right: clamp(20px, 3vw, 40px);
  background: var(--c-cream);
  color: var(--c-ink);
  border-top: 1px solid var(--c-cream);
}

.page-about .ab-section--band .band-num {
  background: var(--c-ink);
  color: var(--c-cream);
}

.page-about .ab-section--band .band-label {
  color: var(--ab-cream-ink);
}

.page-about .ab-section--band .section-title {
  color: var(--c-ink);
}

.page-about .ab-eco {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 3.4vw, 44px);
  margin-top: clamp(24px, 3.4vw, 38px);
}

.page-about .ab-section--band .ab-media {
  margin-top: 0;
}

.page-about .ab-section--band .ab-media img {
  border-color: rgba(10, 42, 32, 0.22);
}

.page-about .ab-section--band .ab-media-cap {
  color: var(--ab-cream-ink);
}

.page-about .ab-assert--dark {
  margin-top: 0;
  color: var(--c-deep);
}

.page-about .ab-p--dark {
  color: var(--ab-cream-ink);
}

.page-about .ab-link--dark {
  color: var(--c-ink);
  border-bottom-color: var(--c-teal);
}

.page-about .ab-link--dark:hover,
.page-about .ab-link--dark:focus-visible {
  color: var(--c-deep);
  border-bottom-color: var(--c-deep);
}

/* ---------- 版本时间轴 ---------- */
.page-about .ab-timeline {
  position: relative;
  margin: clamp(28px, 4vw, 44px) 0 0;
  padding: 0 0 0 28px;
  list-style: none;
  border-left: 1px solid var(--c-line);
}

.page-about .ab-tl-item {
  position: relative;
  padding: 0 0 34px 22px;
}

.page-about .ab-tl-item:last-child {
  padding-bottom: 0;
}

.page-about .ab-tl-node {
  position: absolute;
  left: -33px;
  top: 6px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--c-cyan);
  box-shadow: 0 0 0 4px rgba(55, 242, 198, 0.14);
}

.page-about .ab-tl-ver {
  margin: 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 20px;
  line-height: 1;
  letter-spacing: 0.06em;
  color: var(--c-cyan);
}

.page-about .ab-tl-season {
  margin: 8px 0 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--c-mist);
}

.page-about .ab-tl-desc {
  margin: 10px 0 0;
  max-width: 36em;
  font-size: 14px;
  line-height: 1.85;
  color: rgba(245, 242, 234, 0.76);
}

/* ---------- 结尾 CTA ---------- */
.page-about .ab-section--cta {
  padding-bottom: clamp(56px, 8vw, 110px);
}

.page-about .ab-cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(24px, 3vw, 34px);
}

.page-about .ab-contact-line {
  margin: 20px 0 0;
  font-size: 13.5px;
  line-height: 1.9;
  color: var(--c-mist);
}

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

  .page-about .ab-ladder {
    grid-auto-flow: row;
    grid-template-columns: repeat(6, minmax(0, 1fr));
    grid-auto-columns: auto;
    overflow-x: visible;
  }

  .page-about .ab-roles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero-grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
  }

  .page-about .ab-hero-visual {
    order: 0;
  }

  .page-about .ab-cols {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

  .page-about .ab-review {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    align-items: start;
  }

  .page-about .ab-eco {
    grid-template-columns: minmax(0, 0.8fr) minmax(0, 1.2fr);
    align-items: start;
  }
}

@media (min-width: 1024px) {
  .page-about .ab-body {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: clamp(28px, 4vw, 64px);
    align-items: start;
  }

  .page-about .ab-index {
    position: sticky;
    top: calc(var(--header-h) + 28px);
    margin-bottom: 0;
    padding: 0;
    background: transparent;
    border-bottom: 0;
    backdrop-filter: none;
  }

  .page-about .ab-index-title {
    position: static;
    width: auto;
    height: auto;
    clip-path: none;
    overflow: visible;
    margin: 0 0 14px;
    font-family: var(--font-mono);
    font-size: 11px;
    letter-spacing: 0.2em;
    color: var(--c-mist);
  }

  .page-about .ab-index-list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
  }

  .page-about .ab-index-list a {
    padding: 9px 0 9px 14px;
    border: 0;
    border-left: 1px solid var(--c-line);
    border-radius: 0;
    background: transparent;
    transition: color 160ms var(--ease), border-color 160ms var(--ease);
  }

  .page-about .ab-index-list a:hover,
  .page-about .ab-index-list a:focus-visible {
    border-left-color: var(--c-cyan);
    color: var(--c-cyan);
    background: transparent;
  }

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

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-step-bar,
  .page-about .ab-role,
  .page-about .ab-index-list a {
    transition: none;
  }

  .page-about .ab-step:hover .ab-step-bar,
  .page-about .ab-role:hover,
  .page-about .ab-role:focus-within {
    transform: none;
  }
}
</main>