.page-about {
  --ab-sticky: 96px;
  --ab-hair: rgba(59, 74, 85, 0.22);
  --ab-hair-soft: rgba(59, 74, 85, 0.13);
  background: var(--paper);
  color: var(--ink);
}

.page-about .ab-crumbs {
  padding-top: 20px;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  background: linear-gradient(180deg, var(--paper) 0%, var(--paper-2) 100%);
  border-bottom: 1px solid var(--line);
}

.page-about .ab-ridge {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  width: 100%;
  height: 190px;
  fill: var(--cedar);
  opacity: 0.08;
  pointer-events: none;
}

.page-about .ab-hero__inner {
  position: relative;
  display: grid;
  gap: 30px;
  padding: 32px 0 34px;
}

.page-about .ab-hero__kicker {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 18px;
  padding: 6px 12px;
  border: 1px solid var(--line);
  background: rgba(245, 239, 227, 0.75);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: var(--cedar);
}

.page-about .ab-hero__title {
  margin: 0 0 18px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.9rem, 5.4vw, 3.3rem);
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .ab-hero__lede {
  margin: 0 0 26px;
  max-width: 34em;
  font-size: 1.0625rem;
  line-height: 1.78;
  color: var(--ink-soft);
}

.page-about .ab-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .ab-board {
  background: var(--night);
  border: 1px solid var(--line);
  box-shadow: var(--shadow-1);
  padding: 20px 18px 18px;
}

.page-about .ab-board__kicker {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--cedar-mist);
}

.page-about .ab-board__stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: rgba(127, 166, 155, 0.28);
  border: 1px solid rgba(127, 166, 155, 0.28);
}

.page-about .ab-board__cell {
  background: var(--night);
  padding: 15px 14px 13px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .ab-board__num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.75rem;
  line-height: 1;
  color: var(--cyan);
  letter-spacing: -0.02em;
}

.page-about .ab-board__label {
  font-size: 0.8125rem;
  color: rgba(245, 239, 227, 0.72);
}

.page-about .ab-board__note {
  margin: 14px 0 0;
  font-size: 0.8125rem;
  line-height: 1.7;
  color: rgba(245, 239, 227, 0.6);
}

/* ---------- 更新节奏刻度 ---------- */
.page-about .ab-ticker {
  position: relative;
  border-top: 1px solid var(--line);
  background: var(--paper-2);
  padding: 0;
}

.page-about .ab-ticker__track {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  overflow-x: auto;
  scrollbar-width: thin;
  border-left: 1px solid var(--line);
}

.page-about .ab-ticker__item {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 11px 18px;
  border-right: 1px solid var(--line);
  font-size: 0.78rem;
  color: var(--muted);
  white-space: nowrap;
}

.page-about .ab-ticker__num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--clay);
}

/* ---------- 主分栏 ---------- */
.page-about .ab-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 34px;
  padding: 34px 0 8px;
}

.page-about .ab-side {
  display: grid;
  gap: 16px;
  align-content: start;
}

.page-about .ab-side__block {
  border: 1px solid var(--line);
  background: var(--paper-3);
  padding: 14px 14px 16px;
}

.page-about .ab-side__label {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--cedar);
  padding-bottom: 8px;
  border-bottom: 1px solid var(--ab-hair);
}

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

.page-about .ab-side__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 10px;
  align-items: baseline;
  padding: 7px 0;
  border-bottom: 1px solid var(--ab-hair-soft);
  font-size: 0.8125rem;
  color: var(--ink-soft);
}

.page-about .ab-side__row--total {
  border-bottom: 0;
  border-top: 1px solid var(--ab-hair);
  margin-top: 4px;
  padding-top: 10px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .ab-side__num {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--clay);
}

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

.page-about .ab-idx__link {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 10px;
  align-items: baseline;
  padding: 8px 10px;
  border-left: 2px solid transparent;
  font-size: 0.875rem;
  color: var(--ink-soft);
  text-decoration: none;
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.page-about .ab-idx__no {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--cedar-mist);
}

.page-about .ab-idx__link:hover,
.page-about .ab-idx__link:focus-visible {
  background: var(--paper-2);
  color: var(--ink);
}

.page-about .ab-idx__link.is-current {
  border-left-color: var(--clay);
  background: var(--paper-2);
  color: var(--ink);
}

.page-about .ab-idx__link.is-current .ab-idx__no {
  color: var(--clay);
}

/* ---------- 章节 ---------- */
.page-about .ab-sec {
  padding: 30px 0 10px;
  scroll-margin-top: 84px;
}

.page-about .ab-sec__head {
  position: sticky;
  top: 0;
  z-index: 4;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 16px;
  margin: 0 0 22px;
  padding: 12px 16px;
  background: var(--cedar);
  color: var(--paper);
}

.page-about .ab-sec__no {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .ab-sec__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.2rem, 3.4vw, 1.7rem);
  line-height: 1.3;
  letter-spacing: -0.005em;
  color: var(--paper);
}

.page-about .ab-prose {
  margin-bottom: 24px;
}

.page-about .ab-prose p {
  margin: 0 0 16px;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--ink-soft);
}

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

/* ---------- 时间轴 ---------- */
.page-about .ab-tl {
  list-style: none;
  margin: 26px 0 0;
  padding: 4px 0 0 26px;
  border-left: 1px solid var(--line);
}

.page-about .ab-tl__item {
  position: relative;
  padding: 0 0 26px;
}

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

.page-about .ab-tl__item::before {
  content: "";
  position: absolute;
  left: -31px;
  top: 6px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--paper);
  border: 2px solid var(--clay);
}

.page-about .ab-tl__year {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.95rem;
  letter-spacing: 0.04em;
  color: var(--clay);
}

.page-about .ab-tl__title {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.0625rem;
  line-height: 1.4;
  color: var(--ink);
}

.page-about .ab-tl__text {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 图片 ---------- */
.page-about .ab-figure {
  margin: 26px 0 0;
  border: 1px solid var(--line);
  background: var(--night);
  padding: 0;
  overflow: hidden;
}

.page-about .ab-figure img {
  display: block;
  width: 100%;
  height: auto;
  filter: saturate(0.72) contrast(1.04);
}

.page-about .ab-figure .media-frame__caption {
  margin: 0;
  padding: 10px 14px;
  border-top: 1px solid var(--line);
  background: var(--paper-2);
  font-size: 0.8125rem;
  line-height: 1.6;
  color: var(--muted);
}

/* ---------- 覆盖范围 ---------- */
.page-about .ab-coverage {
  display: grid;
  gap: 1px;
  background: var(--ab-hair);
  border: 1px solid var(--line);
  margin-bottom: 24px;
}

.page-about .ab-coverage__col {
  background: var(--paper-3);
  padding: 18px 16px 20px;
}

.page-about .ab-coverage__label {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--cedar);
}

.page-about .ab-tags {
  list-style: none;
  margin: 0 0 12px;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .ab-coverage__text {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .ab-cadence {
  margin-bottom: 4px;
}

/* ---------- 团队分工 ---------- */
.page-about .ab-roles {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .ab-roles__row {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  gap: 6px 14px;
  align-items: baseline;
  padding: 18px 12px;
  border-bottom: 1px solid var(--line);
  transition: background-color 0.2s ease, box-shadow 0.2s ease;
}

.page-about .ab-roles__no {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--cedar-mist);
}

.page-about .ab-roles__name {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 1.0625rem;
  color: var(--ink);
}

.page-about .ab-roles__count {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.5rem;
  line-height: 1;
  color: var(--clay);
}

.page-about .ab-roles__note {
  grid-column: 2 / -1;
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .ab-roles__keys {
  grid-column: 2 / -1;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--cedar-mist);
  transition: color 0.2s ease;
}

.page-about .ab-roles__row:hover,
.page-about .ab-roles__row:focus-within {
  background: var(--paper-2);
  box-shadow: inset 3px 0 0 var(--clay);
}

.page-about .ab-roles__row:hover .ab-roles__keys,
.page-about .ab-roles__row:focus-within .ab-roles__keys {
  color: var(--clay);
}

/* ---------- 服务对象 ---------- */
.page-about .ab-aud {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--ab-hair);
  border: 1px solid var(--line);
}

.page-about .ab-aud__item {
  background: var(--paper);
  padding: 20px 18px 22px;
}

.page-about .ab-aud__tag {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.16em;
  color: var(--cedar);
}

.page-about .ab-aud__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 1.0625rem;
  line-height: 1.4;
  color: var(--ink);
}

.page-about .ab-aud__text {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--muted);
}

/* ---------- 里程碑 ---------- */
.page-about .ab-miles {
  margin-top: 22px;
}

.page-about .ab-mile {
  border: 1px solid var(--line);
  background: var(--paper-2);
  margin-bottom: 10px;
}

.page-about .ab-mile .fold__head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 14px;
  align-items: baseline;
  padding: 14px 16px;
  cursor: pointer;
  list-style: none;
}

.page-about .ab-mile .fold__head::-webkit-details-marker {
  display: none;
}

.page-about .ab-mile__no {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.8125rem;
  color: var(--clay);
}

.page-about .ab-mile__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1rem;
  line-height: 1.45;
  color: var(--ink);
}

.page-about .ab-mile .fold__body {
  padding: 0 16px 16px 16px;
}

.page-about .ab-mile .fold__body p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--muted);
}

.page-about .ab-mile[open] {
  background: var(--paper-3);
}

/* ---------- 长期理由 ---------- */
.page-about .ab-why {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: none;
}

.page-about .ab-why__item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 16px;
  padding: 20px 0;
  border-top: 1px solid var(--line);
}

.page-about .ab-why__item:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .ab-why__no {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.5rem;
  line-height: 1;
  color: var(--cedar-mist);
}

.page-about .ab-why__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 1.0625rem;
  line-height: 1.4;
  color: var(--ink);
}

.page-about .ab-why__text {
  grid-column: 2 / -1;
  margin: 6px 0 0;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--muted);
}

/* ---------- 联系 ---------- */
.page-about .ab-contact__body {
  border: 1px solid var(--line);
  background: var(--night);
  padding: 24px 20px 26px;
}

.page-about .ab-contact__text {
  margin: 0 0 20px;
  max-width: 34em;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: rgba(245, 239, 227, 0.82);
}

.page-about .ab-contact__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 页尾签章条 ---------- */
.page-about .ab-seal {
  margin-top: 46px;
  border-top: 1px solid var(--line);
  background: var(--paper-2);
}

.page-about .ab-seal__inner {
  display: grid;
  gap: 14px;
  padding: 28px 0 34px;
}

.page-about .ab-seal__mark {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 1.25rem;
  letter-spacing: 0.02em;
  color: var(--cedar-deep);
}

.page-about .ab-seal__text {
  margin: 0;
  max-width: 48em;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--muted);
}

.page-about .ab-seal__links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 22px;
}

.page-about .ab-seal__links a {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  color: var(--cedar);
  text-decoration: none;
  border-bottom: 1px solid var(--ab-hair);
  padding-bottom: 2px;
}

.page-about .ab-seal__links a:hover,
.page-about .ab-seal__links a:focus-visible {
  color: var(--clay);
  border-bottom-color: var(--clay);
}

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

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

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

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

/* ---------- 桌面 ---------- */
@media (min-width: 900px) {
  .page-about .ab-hero__inner {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    gap: 46px;
    align-items: start;
    padding: 56px 0 52px;
  }

  .page-about .ab-hero__lede {
    font-size: 1.125rem;
  }

  .page-about .ab-seal__inner {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: end;
    gap: 18px 36px;
  }

  .page-about .ab-seal__links {
    justify-content: flex-end;
  }
}

@media (min-width: 1080px) {
  .page-about .ab-split {
    grid-template-columns: minmax(0, 7fr) minmax(0, 3fr);
    gap: 48px;
    padding: 52px 0 12px;
  }

  .page-about .ab-side {
    position: sticky;
    top: var(--ab-sticky);
  }

  .page-about .ab-sec {
    padding: 34px 0 10px;
  }

  .page-about .ab-why__item {
    grid-template-columns: 52px minmax(0, 1fr);
    padding: 24px 0;
  }

  .page-about .ab-why__no {
    font-size: 1.75rem;
  }
}

/* ---------- 窄屏与动效 ---------- */
@media (max-width: 719px) {
  .page-about .ab-sec__head {
    position: static;
  }

  .page-about .ab-roles__row {
    padding: 16px 10px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-idx__link,
  .page-about .ab-roles__row,
  .page-about .ab-roles__keys {
    transition: none;
  }
}
</main>