.page-about {
  --ab-line: var(--warm-200);
  background: var(--paper);
  color: var(--body-ink);
  font-family: var(--sans);
}

/* ---------- 首屏框景 ---------- */
.page-about .ab-hero {
  padding: clamp(34px, 6vw, 78px) 0 clamp(38px, 6vw, 70px);
}

.page-about .ab-hero__frame {
  position: relative;
  padding: clamp(20px, 4vw, 52px);
  border: 1px solid var(--ab-line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.72);
}

.page-about .ab-hero__frame::before,
.page-about .ab-hero__frame::after {
  content: "";
  position: absolute;
  width: 20px;
  height: 20px;
  pointer-events: none;
}

.page-about .ab-hero__frame::before {
  top: -1px;
  left: -1px;
  border-top: 2px solid var(--amber);
  border-left: 2px solid var(--amber);
  border-top-left-radius: 8px;
}

.page-about .ab-hero__frame::after {
  right: -1px;
  bottom: -1px;
  border-right: 2px solid var(--amber);
  border-bottom: 2px solid var(--amber);
  border-bottom-right-radius: 8px;
}

.page-about .ab-hero__frame .breadcrumbs {
  margin: 0 0 20px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--slate);
}

.page-about .ab-hero__kicker {
  margin: 0 0 14px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--amber);
}

.page-about .ab-hero h1 {
  margin: 0;
  max-width: 15em;
  color: var(--ink);
  font-size: clamp(27px, 5.4vw, 52px);
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: -0.02em;
}

.page-about .ab-hero .lede {
  margin: 20px 0 0;
  max-width: 34em;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.85;
  color: var(--body-ink);
}

.page-about .ab-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

/* ---------- 区块骨架 ---------- */
.page-about .ab-section {
  padding: clamp(42px, 7vw, 82px) 0;
  border-top: 1px solid var(--ab-line);
}

.page-about .ab-head {
  max-width: 780px;
  margin-bottom: clamp(26px, 4vw, 42px);
}

.page-about .ab-head .eyebrow {
  margin: 0 0 12px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--amber);
}

.page-about .ab-head h2 {
  margin: 0;
  color: var(--ink);
  font-size: clamp(22px, 3.3vw, 34px);
  font-weight: 800;
  line-height: 1.24;
  letter-spacing: -0.02em;
}

.page-about .ab-head .ab-sub {
  margin: 14px 0 0;
  max-width: 36em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--slate);
}

.page-about .ab-link {
  color: var(--celadon);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

.page-about .prose {
  max-width: 34em;
}

.page-about .prose p {
  margin: 0 0 1.1em;
  line-height: 1.85;
}

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

/* ---------- 起点 3/7 分栏 ---------- */
.page-about .ab-cols {
  display: grid;
  gap: 26px;
}

.page-about .ab-note {
  padding: 18px 16px;
  border: 1px solid var(--ab-line);
  border-left: 3px solid var(--amber);
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.72);
}

.page-about .ab-note__label {
  margin: 0 0 8px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--ink);
}

.page-about .ab-note__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--slate);
}

/* ---------- 年份刻度尺 ---------- */
.page-about .ab-ruler {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 8px;
  margin: 0 0 34px;
  padding: 0 0 10px;
  border-bottom: 1px solid var(--ab-line);
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--slate);
}

.page-about .ab-ruler span {
  position: relative;
}

.page-about .ab-ruler span::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: -11px;
  width: 1px;
  height: 6px;
  background: var(--amber);
  transform: translateX(-50%);
}

/* ---------- 时间轴 ---------- */
.page-about .ab-tl {
  margin: 0;
  padding: 0;
  list-style: none;
}

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

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

.page-about .ab-tl__item::before {
  content: "";
  position: absolute;
  left: 61px;
  top: 18px;
  bottom: 0;
  width: 2px;
  background: var(--ab-line);
}

.page-about .ab-tl__item:last-child::before {
  display: none;
}

.page-about .ab-tl__q {
  position: relative;
  display: block;
  min-height: 24px;
  padding-left: 84px;
  padding-right: 26px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .ab-tl__q::marker {
  content: "";
}

.page-about .ab-tl__q::before {
  content: "";
  position: absolute;
  left: 56px;
  top: 4px;
  width: 12px;
  height: 12px;
  box-sizing: border-box;
  border: 2px solid var(--amber);
  border-radius: 2px;
  background: var(--paper);
}

.page-about .ab-tl__q::after {
  content: "+";
  position: absolute;
  right: 0;
  top: -2px;
  font-family: var(--mono);
  font-size: 18px;
  line-height: 1;
  color: var(--slate);
}

.page-about .ab-tl__node[open] .ab-tl__q::after {
  content: "−";
  color: var(--amber);
}

.page-about .ab-tl__year {
  position: absolute;
  left: 0;
  top: 0;
  width: 44px;
  font-family: var(--mono);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--ink);
}

.page-about .ab-tl__title {
  display: block;
  font-size: clamp(16px, 2vw, 19px);
  font-weight: 700;
  line-height: 1.5;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .ab-tl__body {
  padding: 10px 0 0 84px;
}

.page-about .ab-tl__body p {
  margin: 0;
  max-width: 34em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--body-ink);
}

/* ---------- 图片框 ---------- */
.page-about .ab-fig {
  margin: 0 0 30px;
  border: 1px solid var(--ab-line);
  border-radius: 8px;
  overflow: hidden;
  background: var(--warm-200);
}

.page-about .ab-fig img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .ab-fig__cap {
  padding: 10px 14px;
  border-top: 1px solid var(--ab-line);
  background: rgba(255, 255, 255, 0.72);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  line-height: 1.7;
  color: var(--slate);
}

.page-about .ab-fig--tall {
  margin-bottom: 0;
}

/* ---------- 团队分工 ---------- */
.page-about .ab-org {
  position: relative;
  margin: 0 0 34px;
}

.page-about .ab-org__list {
  position: relative;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-org__unit {
  position: relative;
  padding: 16px 14px;
  border-radius: 6px;
  background: var(--navy-700);
  color: #ffffff;
}

.page-about .ab-org__role {
  display: block;
  font-size: 16px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.page-about .ab-org__desc {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--amber-l);
}

.page-about .ab-team-flow {
  max-width: 40em;
}

/* ---------- 适配与安全 ---------- */
.page-about .ab-split {
  display: grid;
  gap: 30px;
}

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

.page-about .ab-metrics__row {
  padding: 18px 0;
  border-top: 1px solid var(--ab-line);
}

.page-about .ab-metrics__row:first-child {
  padding-top: 0;
  border-top: none;
}

.page-about .ab-metrics dt {
  font-family: var(--mono);
  font-size: clamp(18px, 2.4vw, 22px);
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--ink);
}

.page-about .ab-metrics dd {
  margin: 6px 0 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--body-ink);
}

/* ---------- 四条要求 ---------- */
.page-about .ab-rules {
  display: grid;
  gap: 16px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-rules__cell {
  position: relative;
  padding: 24px 20px 22px;
  border: 1px solid var(--ab-line);
  border-radius: 6px;
  background: #ffffff;
}

.page-about .ab-rules__no {
  display: block;
  margin-bottom: 10px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--amber);
}

.page-about .ab-rules__cell h3 {
  margin: 0 0 10px;
  font-size: 19px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .ab-rules__cell p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--body-ink);
}

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

.page-about .ab-next__item a {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 4px 14px;
  padding: 20px 18px;
  border: 1px solid var(--ab-line);
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.6);
  color: inherit;
  text-decoration: none;
  transition: border-color 220ms var(--ease), transform 220ms var(--ease);
}

.page-about .ab-next__item a:hover {
  border-color: var(--amber);
  transform: translateY(-2px);
}

.page-about .ab-next__no {
  grid-column: 1;
  grid-row: 1;
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--amber);
}

.page-about .ab-next__title {
  grid-column: 2;
  grid-row: 1;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .ab-next__text {
  grid-column: 1 / -1;
  grid-row: 2;
  font-size: 14px;
  line-height: 1.75;
  color: var(--slate);
}

/* ---------- 收束条 ---------- */
.page-about .ab-outro {
  background: var(--ink);
  color: #ffffff;
}

.page-about .ab-outro__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding-top: 40px;
  padding-bottom: 40px;
}

.page-about .ab-outro__line {
  margin: 0;
  max-width: 30em;
  font-size: clamp(16px, 2vw, 19px);
  font-weight: 700;
  line-height: 1.6;
  letter-spacing: -0.01em;
  color: #ffffff;
}

/* ---------- 断点 ---------- */
@media (min-width: 620px) {
  .page-about .ab-metrics__row {
    display: grid;
    grid-template-columns: 128px minmax(0, 1fr);
    gap: 6px 24px;
    align-items: baseline;
  }

  .page-about .ab-metrics dd {
    margin: 0;
  }

  .page-about .ab-next {
    gap: 16px;
  }
}

@media (min-width: 860px) {
  .page-about .ab-cols {
    grid-template-columns: minmax(0, 1fr) 264px;
    gap: 56px;
    align-items: start;
  }

  .page-about .ab-split {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    gap: 48px;
    align-items: start;
  }

  .page-about .ab-rules {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 20px;
  }

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

  .page-about .ab-next__item a {
    grid-template-columns: minmax(0, 1fr);
    align-content: start;
    height: 100%;
    padding: 22px 20px;
  }

  .page-about .ab-next__no {
    grid-column: 1;
    grid-row: 1;
  }

  .page-about .ab-next__title {
    grid-column: 1;
    grid-row: 2;
  }

  .page-about .ab-next__text {
    grid-column: 1;
    grid-row: 3;
    margin-top: 6px;
  }
}

@media (min-width: 900px) {
  .page-about .ab-org {
    padding-top: 40px;
    margin-bottom: 40px;
  }

  .page-about .ab-org::before {
    content: "";
    position: absolute;
    top: 20px;
    left: 5%;
    right: 5%;
    height: 2px;
    background: var(--ab-line);
  }

  .page-about .ab-org__list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 16px;
  }

  .page-about .ab-org__unit::before {
    content: "";
    position: absolute;
    left: 22px;
    top: -20px;
    width: 2px;
    height: 20px;
    background: var(--ab-line);
  }

  .page-about .ab-org__unit::after {
    content: "";
    position: absolute;
    left: 19px;
    top: -24px;
    width: 8px;
    height: 8px;
    box-sizing: border-box;
    border-radius: 50%;
    background: var(--amber);
  }

  .page-about .ab-tl__item {
    padding-bottom: 30px;
  }
}

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

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