.page-about {
  --ab-accent: var(--lime);
  --ab-soft: var(--line-faint);
}

/* ---------- 首屏 ---------- */

.page-about .ab-hero {
  padding-top: 6px;
}

.page-about .ab-hero__grid {
  display: grid;
  gap: 32px;
}

.page-about .ab-hero__title {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(34px, 7.4vw, 74px);
  line-height: 1.05;
  letter-spacing: 0.05em;
  color: var(--chalk);
  margin: 14px 0 22px;
}

.page-about .ab-hero__text {
  max-width: 62ch;
  margin: 0 0 16px;
  font-size: 16px;
  line-height: 1.8;
  color: var(--chalk);
}

.page-about .ab-hero__text + .ab-hero__text {
  color: var(--index);
}

.page-about .ab-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .ab-hero__panel {
  position: relative;
  padding-top: 30px;
}

.page-about .ab-hero__panel::before {
  content: "";
  position: absolute;
  top: 16px;
  left: 20px;
  width: 46px;
  height: 2px;
  background: var(--ab-accent);
}

.page-about .ab-facts {
  margin: 16px 0 0;
}

.page-about .ab-facts__row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
  padding: 11px 0;
  border-bottom: 1px solid var(--line-faint);
}

.page-about .ab-facts__row:last-child {
  border-bottom: 0;
}

.page-about .ab-facts dt {
  margin: 0;
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--index);
}

.page-about .ab-facts dd {
  margin: 0;
  font-size: 15px;
  color: var(--chalk);
}

/* ---------- 章节标题 ---------- */

.page-about .ab-head {
  margin-bottom: 30px;
}

.page-about .ab-head h2 {
  font-family: var(--font-body);
  font-weight: 600;
  font-size: clamp(21px, 3.6vw, 30px);
  line-height: 1.35;
  color: var(--chalk);
  margin: 10px 0 12px;
}

.page-about .ab-head__sub {
  max-width: 64ch;
  margin: 0;
  font-size: 16px;
  line-height: 1.8;
  color: var(--index);
}

/* ---------- 两条主线 ---------- */

.page-about .ab-lines__grid {
  display: grid;
  gap: 20px;
}

.page-about .ab-line {
  padding: 26px 22px 24px;
}

.page-about .ab-line--a {
  border-left: 2px solid var(--ab-accent);
}

.page-about .ab-line--b {
  border-left: 2px solid var(--line);
}

.page-about .ab-line__title {
  margin: 0 0 12px;
  font-size: 19px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--chalk);
}

.page-about .ab-line__desc {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--index);
}

.page-about .ab-line__list {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
}

.page-about .ab-line__list li {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 10px 0;
  border-top: 1px solid var(--ab-soft);
  font-size: 15px;
  color: var(--chalk);
}

.page-about .ab-line__list .mono {
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--index);
}

/* ---------- 图片 ---------- */

.page-about .ab-figure {
  margin: 34px 0 0;
}

.page-about .ab-figure__cap {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  letter-spacing: 0.04em;
  color: var(--index);
}

.page-about .frame img {
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------- 四步流程 ---------- */

.page-about .ab-flow {
  list-style: none;
  display: grid;
  gap: 22px;
  margin: 0;
  padding: 0;
}

.page-about .ab-flow__step {
  position: relative;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.page-about .ab-flow__step::before {
  content: "";
  position: absolute;
  top: -3px;
  left: 0;
  width: 6px;
  height: 6px;
  background: var(--ab-accent);
}

.page-about .ab-flow__no {
  margin: 0 0 8px;
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--index);
}

.page-about .ab-flow__step h3 {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 600;
  color: var(--chalk);
}

.page-about .ab-flow__step p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--index);
}

/* ---------- 团队分组 ---------- */

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

.page-about .ab-roster__item {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 6px 16px;
  padding: 20px 0;
  border-top: 1px solid var(--ab-soft);
}

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

.page-about .ab-roster__no {
  grid-row: 1 / span 2;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--ab-accent);
}

.page-about .ab-roster__name {
  grid-column: 2;
  font-size: 17px;
  font-weight: 600;
  color: var(--chalk);
}

.page-about .ab-roster__desc {
  grid-column: 2;
  font-size: 15px;
  line-height: 1.75;
  color: var(--index);
}

/* ---------- 版本历程 ---------- */

.page-about .ab-history__grid {
  display: grid;
  gap: 34px;
}

.page-about .ab-tl {
  list-style: none;
  position: relative;
  margin: 0;
  padding: 0 0 0 34px;
}

.page-about .ab-tl::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--line);
}

.page-about .ab-tl__item {
  position: relative;
  padding-bottom: 28px;
}

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

.page-about .ab-tl__item::before {
  content: "";
  position: absolute;
  left: -34px;
  top: 7px;
  width: 11px;
  height: 11px;
  background: var(--ink);
  border: 1px solid var(--line);
}

.page-about .ab-tl__no {
  margin: 0 0 6px;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--ab-accent);
}

.page-about .ab-tl__item h3 {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 600;
  color: var(--chalk);
}

.page-about .ab-tl__item p {
  margin: 0;
  max-width: 52ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--index);
}

.page-about .ab-history__aside {
  max-width: 340px;
}

/* ---------- 更新节奏 ---------- */

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

.page-about .ab-cadence__list li {
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: 10px 18px;
  align-items: baseline;
  padding: 16px 0;
  border-top: 1px solid var(--ab-soft);
  font-size: 15px;
  line-height: 1.75;
  color: var(--chalk);
}

.page-about .ab-cadence__list li:last-child {
  border-bottom: 1px solid var(--ab-soft);
}

.page-about .ab-cadence__key {
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--ab-accent);
}

.page-about .ab-cadence__more {
  margin: 22px 0 0;
  font-size: 15px;
}

.page-about .ab-cadence__more a {
  color: var(--ab-accent);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  padding-bottom: 2px;
  transition: border-color var(--speed) var(--ease);
}

.page-about .ab-cadence__more a:hover,
.page-about .ab-cadence__more a:focus-visible {
  border-color: var(--ab-accent);
}

/* ---------- 理由清单 ---------- */

.page-about .ab-reasons {
  list-style: none;
  display: grid;
  gap: 26px;
  margin: 0;
  padding: 0;
}

.page-about .ab-reasons li {
  padding-left: 18px;
  border-left: 1px solid var(--line);
}

.page-about .ab-reasons h3 {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: var(--chalk);
}

.page-about .ab-reasons p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--index);
}

/* ---------- 恢复提示 ---------- */

.page-about .ab-recover {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 16px;
  margin-top: 38px;
  padding: 18px 20px;
  background: var(--stand);
  border: 1px solid var(--line);
  font-size: 15px;
  line-height: 1.75;
  color: var(--index);
}

.page-about .ab-recover__tag {
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--warn);
  border: 1px solid var(--warn);
  padding: 3px 8px;
  white-space: nowrap;
}

.page-about .ab-recover a {
  color: var(--chalk);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  transition: border-color var(--speed) var(--ease), color var(--speed) var(--ease);
}

.page-about .ab-recover a:hover,
.page-about .ab-recover a:focus-visible {
  color: var(--ab-accent);
  border-color: var(--ab-accent);
}

/* ---------- 响应式 ---------- */

@media (min-width: 720px) {
  .page-about .ab-flow {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 30px 32px;
  }

  .page-about .ab-roster__item {
    grid-template-columns: 56px 200px minmax(0, 1fr);
    align-items: baseline;
  }

  .page-about .ab-roster__no {
    grid-row: auto;
  }

  .page-about .ab-reasons {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 30px 40px;
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    align-items: start;
    gap: 56px;
  }

  .page-about .ab-lines__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 32px;
  }

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

  .page-about .ab-history__grid {
    grid-template-columns: minmax(0, 1fr) 300px;
    gap: 48px;
    align-items: start;
  }

  .page-about .ab-history__aside {
    max-width: none;
    position: sticky;
    top: 96px;
  }

  .page-about .ab-cadence__list li {
    grid-template-columns: 140px minmax(0, 1fr);
  }
}

@media (min-width: 1100px) {
  .page-about .ab-line {
    padding: 30px 28px 28px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-cadence__more a,
  .page-about .ab-recover a {
    transition: none;
  }
}