.page-about {
  --ab-rail: 220px;
  --ab-gap: 28px;
  background: var(--ink);
  color: var(--white);
  padding-bottom: 72px;
}

.page-about .section {
  padding-block: 52px;
}

.page-about .ab-sec-head {
  max-width: 62ch;
  margin-bottom: 28px;
}

.page-about .ab-sec-head h2 {
  margin: 10px 0 14px;
  font-size: clamp(26px, 4.6vw, 40px);
  font-weight: 200;
  line-height: 1.18;
  letter-spacing: -0.02em;
}

.page-about .ab-sec-head p {
  margin: 0;
  font-size: 16px;
  line-height: 1.75;
  color: rgba(251, 248, 242, 0.78);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  padding: 12px 0 8px;
}

.page-about .ab-hero .display {
  margin: 14px 0 0;
  font-size: clamp(38px, 9.4vw, 108px);
  font-weight: 200;
  line-height: 0.96;
  letter-spacing: -0.035em;
}

.page-about .ab-hero__lede {
  max-width: 58ch;
  margin: 22px 0 0;
  font-size: 16px;
  line-height: 1.78;
  color: rgba(251, 248, 242, 0.82);
}

.page-about .ab-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2px;
  margin: 32px 0 0;
  padding: 0;
  list-style: none;
  background: var(--rule);
  border: 2px solid var(--rule);
}

.page-about .ab-stats__item {
  background: var(--ink-2);
  padding: 16px 14px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .ab-stats__n {
  font-size: clamp(28px, 6vw, 40px);
  line-height: 1;
  color: var(--orange);
}

.page-about .ab-stats__k {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--gray);
}

/* ---------- 起点 ---------- */
.page-about .ab-origin__grid {
  display: grid;
  gap: 26px;
}

.page-about .ab-origin__copy h2 {
  margin: 10px 0 16px;
  font-size: clamp(26px, 4.6vw, 40px);
  font-weight: 200;
  line-height: 1.18;
  letter-spacing: -0.02em;
}

.page-about .ab-origin__copy p {
  margin: 0 0 14px;
  font-size: 16px;
  line-height: 1.78;
  color: rgba(251, 248, 242, 0.82);
}

.page-about .ab-list {
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
  border-top: 2px solid var(--rule);
}

.page-about .ab-list li {
  position: relative;
  padding: 12px 0 12px 22px;
  border-bottom: 1px solid var(--rule);
  font-size: 15px;
  line-height: 1.6;
}

.page-about .ab-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 20px;
  width: 8px;
  height: 8px;
  background: var(--orange);
  transform: rotate(45deg);
}

.page-about .ab-fig {
  margin: 0;
  border: 2px solid var(--rule-strong);
  box-shadow: var(--shadow-soft);
  transition: filter var(--t2) var(--ease);
}

.page-about .ab-fig:hover {
  filter: contrast(1.08) brightness(1.04);
}

.page-about .ab-fig img,
.page-about .ab-fig .img-frame__cap {
  display: block;
}

/* ---------- 版本时间轴 ---------- */
.page-about .ab-tl {
  display: block;
  width: 100%;
  height: auto;
  max-height: 130px;
  margin: 0 0 26px;
}

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

.page-about .ab-rail ol {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 6px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .ab-rail a {
  display: flex;
  align-items: baseline;
  gap: 8px;
  white-space: nowrap;
  padding: 9px 14px;
  border: 2px solid var(--rule);
  background: var(--ink-2);
  color: var(--white);
  text-decoration: none;
  font-size: 14px;
  font-weight: 700;
  transition: border-color var(--t1) var(--ease), color var(--t1) var(--ease);
}

.page-about .ab-rail a:hover,
.page-about .ab-rail a:focus-visible {
  border-color: var(--orange);
  color: var(--orange-soft);
}

.page-about .ab-rail__no {
  font-family: var(--font-cond);
  font-style: italic;
  font-size: 15px;
  color: var(--orange);
  letter-spacing: 0.04em;
}

.page-about .ab-cards {
  display: grid;
  gap: 22px;
}

.page-about .ab-version {
  position: relative;
  padding: 22px 20px 22px;
  border: 2px solid rgba(251, 248, 242, 0.3);
  box-shadow: var(--shadow-hard);
  scroll-margin-top: calc(var(--bar-h) + var(--nav-h) + 28px);
  transition: transform var(--t2) var(--ease), box-shadow var(--t2) var(--ease);
}

.page-about .ab-version:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-soft);
}

.page-about .ab-version:target {
  outline: 2px solid var(--orange);
  outline-offset: 3px;
}

.page-about .ab-version--wine {
  background: var(--wine);
}

.page-about .ab-version--indigo {
  background: var(--indigo);
}

.page-about .ab-version__top {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding-bottom: 12px;
  border-bottom: 1px solid rgba(251, 248, 242, 0.28);
}

.page-about .ab-version__no {
  font-family: var(--font-cond);
  font-style: italic;
  font-weight: 700;
  font-size: 30px;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--white);
}

.page-about .ab-version__yr {
  font-size: 12px;
  letter-spacing: 0.1em;
  color: rgba(251, 248, 242, 0.72);
}

.page-about .ab-version__title {
  margin: 16px 0 12px;
  font-size: 21px;
  font-weight: 700;
  line-height: 1.35;
}

.page-about .ab-version__why {
  margin: 0 0 16px;
  font-size: 15px;
  line-height: 1.72;
  color: rgba(251, 248, 242, 0.86);
}

.page-about .ab-version__label {
  display: inline-block;
  margin-right: 8px;
  padding: 2px 7px;
  background: rgba(7, 26, 38, 0.42);
  color: var(--orange-soft);
  font-size: 11px;
  letter-spacing: 0.12em;
}

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

.page-about .ab-version__list li {
  padding: 9px 0 9px 18px;
  border-top: 1px solid rgba(251, 248, 242, 0.22);
  font-size: 14.5px;
  line-height: 1.6;
  position: relative;
}

.page-about .ab-version__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 16px;
  width: 7px;
  height: 7px;
  background: var(--teal);
}

.page-about .ab-version__more {
  margin: 18px 0 0;
  font-size: 14px;
}

.page-about .ab-version__more a,
.page-about .ab-source__note a,
.page-about .ab-reach__after a,
.page-about .ab-next__tail a {
  color: var(--orange-soft);
  text-decoration: none;
  border-bottom: 1px solid rgba(255, 178, 122, 0.5);
  padding-bottom: 1px;
  transition: color var(--t1) var(--ease), border-color var(--t1) var(--ease);
}

.page-about .ab-version__more a:hover,
.page-about .ab-source__note a:hover,
.page-about .ab-reach__after a:hover,
.page-about .ab-next__tail a:hover,
.page-about .ab-version__more a:focus-visible,
.page-about .ab-source__note a:focus-visible,
.page-about .ab-reach__after a:focus-visible,
.page-about .ab-next__tail a:focus-visible {
  color: var(--white);
  border-color: var(--white);
}

/* ---------- 团队 ---------- */
.page-about .ab-fig--square {
  max-width: 420px;
  margin-bottom: 24px;
}

.page-about .ab-team__cards {
  display: grid;
  gap: 14px;
  margin-bottom: 32px;
}

.page-about .ab-team__card {
  padding: 18px 16px;
  border: 2px solid var(--rule-strong);
  background: var(--ink-2);
  box-shadow: var(--shadow-soft);
}

.page-about .ab-team__card--edit {
  border-top-color: var(--orange);
}

.page-about .ab-team__card--data {
  border-top-color: var(--teal);
}

.page-about .ab-team__card--tech {
  border-top-color: var(--indigo);
}

.page-about .ab-team__n {
  margin: 0;
  font-size: 34px;
  line-height: 1;
  color: var(--white);
}

.page-about .ab-team__k {
  margin: 8px 0 6px;
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--orange-soft);
}

.page-about .ab-team__d {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.66;
  color: rgba(251, 248, 242, 0.76);
}

.page-about .ab-flow {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: abflow;
  border-left: 2px solid var(--rule);
}

.page-about .ab-flow__step {
  position: relative;
  padding: 0 0 24px 20px;
}

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

.page-about .ab-flow__no {
  display: inline-block;
  margin-bottom: 6px;
  color: var(--teal);
  font-size: 12px;
}

.page-about .ab-flow__t {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 700;
}

.page-about .ab-flow__step p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.7;
  color: rgba(251, 248, 242, 0.76);
}

/* ---------- 数据来源 ---------- */
.page-about .ab-source__grid {
  display: grid;
  gap: 14px;
}

.page-about .ab-source__card {
  padding: 20px 18px;
  background: var(--ink-2);
  border: 2px solid var(--rule-strong);
  transition: border-color var(--t2) var(--ease), transform var(--t2) var(--ease);
}

.page-about .ab-source__card:hover {
  border-color: var(--teal);
  transform: translateY(-4px);
}

.page-about .ab-source__card .coord {
  display: inline-block;
  margin: 0 0 10px;
  color: var(--teal);
  font-size: 12px;
}

.page-about .ab-source__card h3 {
  margin: 0 0 10px;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.4;
}

.page-about .ab-source__card p:last-child {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.7;
  color: rgba(251, 248, 242, 0.76);
}

.page-about .ab-source__note {
  margin: 24px 0 0;
  padding-top: 18px;
  border-top: 2px solid var(--rule);
  font-size: 15px;
  line-height: 1.72;
  color: rgba(251, 248, 242, 0.82);
}

/* ---------- 覆盖 ---------- */
.page-about .ab-fig--wide {
  margin-bottom: 24px;
}

.page-about .ab-reach__nums {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin-bottom: 30px;
}

.page-about .ab-reach__num {
  padding: 16px 14px;
  border: 2px solid var(--rule);
  background: var(--ink-2);
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .ab-reach__v {
  font-size: 24px;
  line-height: 1;
  color: var(--orange);
}

.page-about .ab-reach__k {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--gray);
}

.page-about .ab-table-wrap {
  overflow-x: auto;
  border: 2px solid var(--rule-strong);
  background: var(--ink-2);
}

.page-about .ab-table {
  width: 100%;
  min-width: 520px;
  border-collapse: collapse;
  font-size: 14.5px;
}

.page-about .ab-table__cap {
  caption-side: top;
  text-align: left;
  padding: 14px 16px 10px;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--teal);
}

.page-about .ab-table th,
.page-about .ab-table td {
  padding: 13px 16px;
  text-align: left;
  vertical-align: top;
  line-height: 1.6;
}

.page-about .ab-table thead th {
  font-family: var(--font-cond);
  font-style: italic;
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--teal);
  border-bottom: 2px solid var(--rule-strong);
  background: var(--ink);
}

.page-about .ab-table tbody th {
  font-weight: 700;
  color: var(--white);
  white-space: nowrap;
  border-bottom: 1px solid var(--rule);
}

.page-about .ab-table tbody td {
  color: rgba(251, 248, 242, 0.8);
  border-bottom: 1px solid var(--rule);
}

.page-about .ab-table tbody tr {
  transition: background var(--t1) var(--ease);
}

.page-about .ab-table tbody tr:hover {
  background: rgba(255, 106, 31, 0.12);
}

.page-about .ab-reach__after {
  margin: 22px 0 0;
  font-size: 15px;
  line-height: 1.72;
  color: rgba(251, 248, 242, 0.82);
}

/* ---------- 节奏 ---------- */
.page-about .ab-rhythm {
  display: grid;
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-rhythm__item {
  padding: 18px 16px;
  border: 2px solid var(--rule-strong);
  border-left-width: 6px;
  border-left-color: var(--teal);
  background: var(--ink-2);
}

.page-about .ab-rhythm__time {
  display: inline-block;
  color: var(--orange);
  font-size: 15px;
  letter-spacing: 0.04em;
}

.page-about .ab-rhythm__item h3 {
  margin: 8px 0 8px;
  font-size: 17px;
  font-weight: 700;
}

.page-about .ab-rhythm__item p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.7;
  color: rgba(251, 248, 242, 0.76);
}

.page-about .ab-next__tail {
  margin: 26px 0 0;
  padding-top: 20px;
  border-top: 2px solid var(--rule);
  font-size: 15px;
  line-height: 1.75;
  color: rgba(251, 248, 242, 0.82);
}

/* ---------- 断点 ---------- */
@media (min-width: 720px) {
  .page-about {
    --ab-gap: 36px;
  }

  .page-about .section {
    padding-block: 68px;
  }

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

  .page-about .ab-origin__grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    align-items: start;
    gap: 36px;
  }

  .page-about .ab-team__cards {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .ab-flow {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0 24px;
    border-left: 0;
  }

  .page-about .ab-flow__step {
    padding: 0 0 24px 18px;
    border-left: 2px solid var(--rule);
  }

  .page-about .ab-source__grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .page-about .ab-rhythm {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .ab-fig--square {
    margin-bottom: 28px;
  }
}

@media (min-width: 1024px) {
  .page-about {
    padding-bottom: 96px;
  }

  .page-about .ab-split {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: 48px;
    align-items: start;
  }

  .page-about .ab-rail {
    position: sticky;
    top: calc(var(--bar-h) + var(--nav-h) + 24px);
  }

  .page-about .ab-rail ol {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding: 0;
  }

  .page-about .ab-rail a {
    border: 0;
    border-left: 2px solid var(--rule);
    background: transparent;
    padding: 12px 0 12px 16px;
    font-size: 15px;
  }

  .page-about .ab-rail a:hover,
  .page-about .ab-rail a:focus-visible {
    border-left-color: var(--orange);
  }

  .page-about .ab-version {
    padding: 30px 28px 28px;
  }

  .page-about .ab-version__title {
    font-size: 24px;
  }

  .page-about .ab-origin__grid {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
    gap: 56px;
  }

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

  .page-about .ab-reach__v {
    font-size: 28px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-version,
  .page-about .ab-source__card,
  .page-about .ab-fig {
    transition: none;
  }

  .page-about .ab-version:hover,
  .page-about .ab-source__card:hover {
    transform: none;
  }
}