.page-about {
  --ab-idx-w: 214px;
  --ab-shadow-soft: 8px 8px 0 rgba(28, 92, 72, .55);
  --ab-tap: 4px 4px 0 rgba(28, 92, 72, .5);
}

/* 首屏 */
.page-about .ab-hero {
  display: grid;
  gap: var(--gap);
  padding: 18px 0 34px;
  border-bottom: 2px solid var(--ink-700);
}

.page-about .ab-hero__kicker {
  margin: 0 0 12px;
  color: var(--orange);
  font-size: .78rem;
  letter-spacing: .2em;
  text-transform: uppercase;
}

.page-about .ab-hero__title {
  margin: 0 0 16px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.85rem, 6.2vw, 3.4rem);
  line-height: 1.04;
  letter-spacing: -.02em;
  color: var(--text);
}

.page-about .ab-hero__desc {
  margin: 0 0 22px;
  max-width: 36ch;
  color: var(--text-muted);
  font-size: 1rem;
  line-height: 1.75;
}

.page-about .ab-hero__cta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
}

.page-about .ab-hero__anchor {
  color: var(--cyan);
  font-size: .9rem;
  text-decoration: none;
  border-bottom: 2px solid var(--ink-600);
  padding-bottom: 2px;
}

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

.page-about .ab-hero__media {
  margin: 0;
}

.page-about .ab-hero__stats {
  display: grid;
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-stat {
  display: grid;
  gap: 3px;
  padding: 16px 18px;
  background: var(--ink-800);
  border: 2px solid var(--ink-600);
  box-shadow: var(--ab-tap);
}

.page-about .ab-stat__num {
  font-family: var(--font-mono);
  font-size: clamp(2rem, 8vw, 2.9rem);
  font-weight: 700;
  line-height: 1;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .ab-stat__unit {
  color: var(--orange);
  font-size: .92rem;
  font-weight: 700;
}

.page-about .ab-stat__label {
  color: var(--text-muted);
  font-size: .85rem;
  line-height: 1.6;
}

/* 主体：索引 + 内容流 */
.page-about .ab-body {
  display: grid;
  gap: 8px;
}

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

.page-about .ab-index__title {
  margin: 0 0 10px;
  color: var(--text-muted);
  font-size: .74rem;
  letter-spacing: .18em;
  text-transform: uppercase;
}

.page-about .ab-index__list {
  display: grid;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-index__list a {
  display: block;
  padding: 9px 12px;
  border-left: 3px solid var(--ink-700);
  color: var(--text-muted);
  font-size: .88rem;
  line-height: 1.5;
  text-decoration: none;
  transition: color 180ms var(--ease), border-color 180ms var(--ease), background 180ms var(--ease);
}

.page-about .ab-index__list a:hover,
.page-about .ab-index__list a:focus-visible {
  border-left-color: var(--orange);
  background: var(--ink-800);
  color: var(--text);
}

/* 章节 */
.page-about .ab-sec {
  padding: 34px 0 40px;
  border-top: 2px solid var(--ink-700);
  scroll-margin-top: calc(var(--header-h) + 24px);
}

.page-about .ab-flow > .ab-sec:first-child {
  border-top: 0;
  padding-top: 10px;
}

.page-about .ab-sec__head {
  margin-bottom: 20px;
}

.page-about .sec-idx {
  color: var(--orange);
  font-family: var(--font-mono);
}

.page-about .ab-prose p {
  margin: 0 0 14px;
  color: var(--text-muted);
  font-size: .98rem;
  line-height: 1.8;
  max-width: 42ch;
}

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

.page-about .ab-cols {
  display: grid;
  gap: var(--gap);
}

.page-about .ab-item {
  display: grid;
  gap: 10px;
  align-content: start;
  padding: 20px;
  transition: transform 200ms var(--ease), box-shadow 200ms var(--ease);
}

.page-about .ab-item:hover {
  transform: translateY(-4px);
  box-shadow: 8px 8px 0 rgba(28, 92, 72, .8);
}

.page-about .ab-item .card__title {
  margin: 0;
  color: var(--text);
  font-size: 1.06rem;
  line-height: 1.45;
}

.page-about .ab-item p {
  margin: 0;
  color: var(--text-muted);
  font-size: .93rem;
  line-height: 1.75;
}

/* 数据指标 */
.page-about .ab-figures {
  display: grid;
  gap: 12px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-fig {
  display: grid;
  gap: 2px;
  padding: 14px 16px;
  background: var(--ink-900);
  border: 2px solid var(--ink-600);
}

.page-about .ab-fig__num {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 5vw, 2.05rem);
  line-height: 1.1;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .ab-fig__label {
  color: var(--text-muted);
  font-size: .84rem;
}

.page-about .ab-datafig,
.page-about .ab-vertimeline {
  margin: 26px 0 0;
}

/* 版本时间线 */
.page-about .ab-ver {
  margin-top: 6px;
}

.page-about .ab-ver .tabs__list {
  display: flex;
  gap: 10px;
  margin: 0;
  padding: 4px 0 14px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
  border-bottom: 2px solid var(--ink-700);
  position: relative;
}

.page-about .ab-ver .tabs__btn {
  flex: 0 0 auto;
  display: grid;
  gap: 2px;
  padding: 10px 14px;
  text-align: left;
  background: var(--ink-800);
  border: 2px solid var(--ink-600);
  color: var(--text-muted);
  font-family: var(--font-body);
  font-size: .82rem;
  cursor: pointer;
  transition: background 180ms var(--ease), color 180ms var(--ease), border-color 180ms var(--ease);
}

.page-about .ab-ver .tabs__btn:hover {
  border-color: var(--cyan);
  color: var(--text);
}

.page-about .ab-ver .tabs__btn[aria-selected="true"] {
  background: var(--orange);
  border-color: var(--orange);
  color: var(--ink-900);
}

.page-about .ab-ver__no {
  font-family: var(--font-mono);
  font-size: .82rem;
  letter-spacing: .04em;
}

.page-about .ab-ver__name {
  font-weight: 700;
  font-size: .92rem;
}

.page-about .ab-ver__panel {
  padding: 20px 0 0;
  border-left: 4px solid var(--orange);
  padding-left: 16px;
}

.page-about .ab-ver__panel h3 {
  margin: 0 0 8px;
  color: var(--text);
  font-size: 1.15rem;
  line-height: 1.5;
}

.page-about .ab-ver__panel p {
  margin: 0;
  max-width: 46ch;
  color: var(--text-muted);
  font-size: .95rem;
  line-height: 1.8;
}

.page-about .ab-ver__panel[hidden] {
  display: none;
}

/* 团队比例条 */
.page-about .ab-bars {
  display: grid;
  gap: 16px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-bar__top {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 6px;
}

.page-about .ab-bar__name {
  color: var(--text);
  font-weight: 700;
  font-size: .95rem;
}

.page-about .ab-bar__val {
  color: var(--orange);
  font-size: .88rem;
}

.page-about .ab-bar__track {
  display: block;
  height: 16px;
  background: var(--ink-900);
  border: 2px solid var(--ink-600);
}

.page-about .ab-bar__fill {
  display: block;
  height: 100%;
  background: var(--cyan);
}

.page-about .ab-bar__fill--orange {
  background: var(--orange);
}

.page-about .ab-bar__fill--w31 { width: 31%; }
.page-about .ab-bar__fill--w26 { width: 26%; }
.page-about .ab-bar__fill--w25 { width: 25%; }
.page-about .ab-bar__fill--w18 { width: 18%; }

/* 覆盖网络图 */
.page-about .ab-netfig {
  margin: 26px 0 0;
}

.page-about .ab-net {
  display: block;
  width: 100%;
  height: auto;
  background: var(--ink-900);
  border: 2px solid var(--ink-600);
  box-shadow: var(--ab-tap);
}

.page-about .ab-net__links line {
  stroke: var(--ink-600);
  stroke-width: 1.5;
}

.page-about .ab-net__paths polyline {
  fill: none;
  stroke: var(--orange);
  stroke-width: 2;
  stroke-dasharray: 6 5;
}

.page-about .ab-net__nodes circle {
  fill: var(--cyan);
}

.page-about .ab-net__nodes .ab-net__chk {
  fill: var(--orange);
}

.page-about .ab-net__nodes .ab-net__hub {
  fill: var(--paper);
  stroke: var(--orange);
  stroke-width: 2;
}

.page-about .ab-netfig .media__caption {
  margin-top: 10px;
  color: var(--text-muted);
  font-size: .82rem;
}

/* 纸色提示卡与收尾 */
.page-about .ab-note-card {
  margin-top: var(--gap);
  padding: 20px 22px;
  background: var(--paper);
  border: 2px solid var(--ink-600);
  box-shadow: var(--shadow-hard);
}

.page-about .ab-note-card p {
  margin: 0;
  color: var(--ink-text);
  font-size: .95rem;
  line-height: 1.8;
  max-width: 56ch;
}

.page-about .ab-note-card a {
  color: var(--orange-deep);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .ab-cta {
  display: grid;
  gap: 14px;
  margin: 30px 0 64px;
  padding: 26px 24px;
  background: var(--paper);
  border: 2px solid var(--ink-600);
  box-shadow: var(--shadow-hard);
}

.page-about .ab-cta h2 {
  margin: 0;
  color: var(--ink-text);
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.25rem, 4vw, 1.85rem);
  letter-spacing: -.01em;
  line-height: 1.3;
}

.page-about .ab-cta p {
  margin: 0;
  max-width: 52ch;
  color: var(--ink-text-muted);
  font-size: .95rem;
  line-height: 1.8;
}

.page-about .ab-cta p a {
  color: var(--orange-deep);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .ab-cta__row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
}

.page-about .ab-cta__link {
  color: var(--ink-text);
  font-weight: 700;
  font-size: .92rem;
  text-decoration: none;
  border-bottom: 2px solid var(--orange);
  padding-bottom: 2px;
}

/* 平板与桌面 */
@media (min-width: 640px) {
  .page-about .ab-hero__stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .page-about .ab-cols {
    grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, .92fr);
    grid-template-areas:
      "lead media"
      "stats stats";
    align-items: start;
    column-gap: 40px;
  }

  .page-about .ab-hero__lead { grid-area: lead; }
  .page-about .ab-hero__media { grid-area: media; }
  .page-about .ab-hero__stats { grid-area: stats; }

  .page-about .ab-hero__title {
    font-size: clamp(2.2rem, 4.4vw, 3.4rem);
  }

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

  .page-about .ab-cta {
    grid-template-columns: minmax(0, 1fr);
    padding: 32px 30px;
  }
}

@media (min-width: 1024px) {
  .page-about .ab-body {
    grid-template-columns: var(--ab-idx-w) minmax(0, 1fr);
    column-gap: 48px;
    align-items: start;
  }

  .page-about .ab-index {
    display: block;
    position: sticky;
    top: calc(var(--header-h) + 28px);
    padding-top: 12px;
  }

  .page-about .ab-sec {
    padding: 42px 0 48px;
  }

  .page-about .ab-flow > .ab-sec:first-child {
    padding-top: 14px;
  }

  .page-about .ab-cta {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, .6fr);
    align-items: center;
    column-gap: 32px;
  }

  .page-about .ab-cta h2,
  .page-about .ab-cta p {
    grid-column: 1;
  }

  .page-about .ab-cta__row {
    grid-column: 2;
    grid-row: 1 / span 2;
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-item,
  .page-about .ab-index__list a,
  .page-about .ab-ver .tabs__btn {
    transition-duration: 120ms;
  }

  .page-about .ab-item:hover {
    transform: none;
  }
}