.page-about {
  --ab-rail-w: 96px;
}

/* ---------- 面包屑 ---------- */
.page-about .crumbs {
  padding-top: 20px;
  font-size: var(--fs-12);
  letter-spacing: .04em;
}
.page-about .crumbs a {
  color: var(--graphite);
}
.page-about .crumbs a:hover {
  color: var(--orange);
}
.page-about .crumbs [aria-current="page"] {
  color: var(--char);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  padding: 24px 0 44px;
}
.page-about .ab-hero::before {
  display: none;
}
.page-about .ab-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 32px;
  align-items: end;
}
.page-about .eyebrow {
  margin: 0 0 14px;
  font-size: var(--fs-12);
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--graphite);
}
.page-about .ab-hero h1 {
  margin: 0;
  font-size: clamp(30px, 6.2vw, var(--fs-49));
  font-weight: 900;
  line-height: 1.16;
  letter-spacing: -.02em;
  color: var(--char);
  max-width: 20em;
}
.page-about .ab-hero .lede {
  margin: 20px 0 0;
  font-size: var(--fs-16);
  line-height: 1.8;
  color: var(--char);
  max-width: 42em;
}
.page-about .ab-hero__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 28px;
  margin: 28px 0 0;
  padding: 18px 0 0;
  border-top: 1px solid var(--line-2);
}
.page-about .ab-hero__meta-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.page-about .ab-hero__meta dt {
  font-size: var(--fs-25);
  font-weight: 700;
  line-height: 1;
  color: var(--ink);
}
.page-about .ab-hero__meta dd {
  margin: 0;
  font-size: var(--fs-12);
  color: var(--graphite);
}
.page-about .ab-hero__fig {
  margin: 0;
}

/* ---------- 主体：刻度轴 + 章节 ---------- */
.page-about .ab-body {
  display: grid;
  gap: 36px;
  padding-bottom: 72px;
}
.page-about .ab-rail {
  display: none;
}

/* ---------- 章节 ---------- */
.page-about .ab-chapters {
  display: flex;
  flex-direction: column;
  gap: 64px;
  min-width: 0;
}
.page-about .ab-ch {
  min-width: 0;
}
.page-about .ab-ch__head {
  display: flex;
  align-items: baseline;
  gap: 18px;
}
.page-about .ab-ch__num {
  flex: none;
  font-size: clamp(28px, 5vw, var(--fs-39));
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--orange);
}
.page-about .ab-ch__head h2 {
  margin: 0;
  font-size: clamp(22px, 4.4vw, var(--fs-31));
  font-weight: 900;
  line-height: 1.25;
  letter-spacing: -.02em;
  color: var(--char);
}
.page-about .ab-ch__rule {
  height: 1px;
  margin: 18px 0 26px;
  background: var(--line-2);
}
.page-about .ab-ch__lead {
  margin: 0 0 22px;
  font-size: var(--fs-16);
  line-height: 1.75;
  color: var(--graphite);
  max-width: 44em;
}
.page-about .ab-ch__body {
  display: grid;
  gap: 20px;
}
.page-about .ab-ch__body p {
  margin: 0 0 18px;
  font-size: var(--fs-16);
  line-height: 1.8;
  color: var(--char);
}
.page-about .ab-ch__body p:last-child {
  margin-bottom: 0;
}
.page-about .ab-ch__figure {
  margin: 0 0 28px;
}

/* ---------- 可展开条目 ---------- */
.page-about .ab-steps .disclosure__item {
  border-bottom: 1px solid var(--line);
  background: transparent;
}
.page-about .ab-steps .disclosure__item:first-child {
  border-top: 1px solid var(--line);
}
.page-about .ab-steps .disclosure__btn {
  display: grid;
  grid-template-columns: minmax(0, auto) minmax(0, 1fr) 20px;
  align-items: center;
  gap: 14px;
  width: 100%;
  padding: 18px 4px;
  border: 0;
  background: transparent;
  text-align: left;
  cursor: pointer;
  color: inherit;
  transition: background .18s ease;
}
.page-about .ab-steps .disclosure__btn:hover {
  background: var(--paper-2);
}
.page-about .ab-steps .disclosure__btn:focus-visible {
  outline: 2px solid var(--orange);
  outline-offset: -2px;
}
.page-about .ab-steps .disclosure__idx {
  font-size: var(--fs-12);
  letter-spacing: .06em;
  color: var(--orange);
  white-space: nowrap;
}
.page-about .ab-steps .disclosure__title {
  font-size: var(--fs-16);
  font-weight: 700;
  color: var(--char);
  letter-spacing: -.01em;
}
.page-about .ab-steps .disclosure__mark {
  position: relative;
  width: 14px;
  height: 14px;
  justify-self: end;
}
.page-about .ab-steps .disclosure__mark::before,
.page-about .ab-steps .disclosure__mark::after {
  content: "";
  position: absolute;
  background: var(--ink);
  transition: transform .22s ease, opacity .22s ease;
}
.page-about .ab-steps .disclosure__mark::before {
  left: 0;
  top: 6px;
  width: 14px;
  height: 1px;
}
.page-about .ab-steps .disclosure__mark::after {
  left: 6px;
  top: 0;
  width: 1px;
  height: 14px;
}
.page-about .ab-steps .disclosure__panel {
  padding: 0 4px 20px 4px;
}
.page-about .ab-steps .disclosure__panel p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--graphite);
  max-width: 52em;
}

/* ---------- 团队三条线 ---------- */
.page-about .ab-team {
  display: grid;
  gap: 28px;
}
.page-about .ab-team__cards {
  display: grid;
  gap: 14px;
}
.page-about .ab-team__card {
  position: relative;
  padding: 22px 20px 22px 22px;
  background: var(--paper-2);
  border: 1px solid var(--line-2);
  border-left: 3px solid var(--ink);
  transition: transform .18s ease, border-color .18s ease, background .18s ease;
}
.page-about .ab-team__card:hover {
  transform: translateY(-2px);
  border-color: var(--orange);
  border-left-color: var(--orange);
  background: var(--paper);
}
.page-about .ab-team__role {
  margin: 0 0 10px;
  font-size: var(--fs-12);
  letter-spacing: .08em;
  color: var(--orange);
}
.page-about .ab-team__card h3 {
  margin: 0 0 10px;
  font-size: var(--fs-20);
  font-weight: 900;
  letter-spacing: -.01em;
  color: var(--char);
}
.page-about .ab-team__desc {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--graphite);
  transition: color .18s ease;
}
.page-about .ab-team__card:hover .ab-team__desc {
  color: var(--char);
}
.page-about .ab-team__fig {
  margin: 0;
}

/* ---------- 三件坚持 ---------- */
.page-about .ab-pledge {
  position: relative;
  overflow: hidden;
  padding: 32px 22px;
  background: var(--ink);
  color: var(--paper);
}
.page-about .ab-pledge::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(246, 241, 228, .06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(246, 241, 228, .06) 1px, transparent 1px);
  background-size: 32px 32px;
  pointer-events: none;
}
.page-about .ab-pledge__list {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 26px;
}
.page-about .ab-pledge__item {
  padding-top: 22px;
  border-top: 1px solid var(--line-paper);
}
.page-about .ab-pledge__item:first-child {
  padding-top: 0;
  border-top: 0;
}
.page-about .ab-pledge__idx {
  display: block;
  margin-bottom: 10px;
  font-size: var(--fs-12);
  letter-spacing: .12em;
  color: var(--orange-soft);
}
.page-about .ab-pledge__item h3 {
  margin: 0 0 10px;
  font-size: var(--fs-20);
  font-weight: 900;
  letter-spacing: -.01em;
  color: var(--cream);
}
.page-about .ab-pledge__item p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--paper);
  opacity: .88;
  max-width: 48em;
}

/* ---------- 合作与认可 ---------- */
.page-about .ab-partners {
  display: grid;
  gap: 14px;
}
.page-about .ab-partners__item {
  padding: 22px 20px;
  border: 1px solid var(--line-2);
  background: var(--paper);
  transition: border-color .18s ease, background .18s ease;
}
.page-about .ab-partners__item:hover {
  border-color: var(--orange);
  background: var(--paper-2);
}
.page-about .ab-partners__tag {
  display: inline-block;
  margin: 0 0 12px;
  padding: 3px 9px;
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--ink);
  background: var(--orange-soft);
}
.page-about .ab-partners__item h3 {
  margin: 0 0 10px;
  font-size: var(--fs-20);
  font-weight: 900;
  letter-spacing: -.01em;
  color: var(--char);
}
.page-about .ab-partners__item p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--graphite);
}

/* ---------- 收尾入口 ---------- */
.page-about .ab-cta {
  padding: 30px 22px;
  border: 1px solid var(--line-2);
  background: var(--paper-2);
}
.page-about .ab-cta h2 {
  margin: 0 0 12px;
  font-size: var(--fs-25);
  font-weight: 900;
  letter-spacing: -.01em;
  color: var(--char);
}
.page-about .ab-cta p {
  margin: 0 0 22px;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--graphite);
  max-width: 40em;
}
.page-about .ab-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 窄屏防护 ---------- */
.page-about .ab-hero h1,
.page-about .ab-ch__head h2,
.page-about .ab-steps .disclosure__title {
  overflow-wrap: anywhere;
}

/* ---------- 平板 ---------- */
@media (min-width: 700px) {
  .page-about .ab-hero {
    padding: 32px 0 56px;
  }
  .page-about .ab-ch__body--split {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 36px;
  }
  .page-about .ab-team__cards {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
  }
  .page-about .ab-partners {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }
  .page-about .ab-pledge {
    padding: 40px 32px;
  }
  .page-about .ab-cta {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 32px;
    padding: 34px 32px;
  }
  .page-about .ab-cta p {
    margin-bottom: 0;
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 1000px) {
  .page-about .ab-hero::before {
    display: block;
    content: "";
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: auto;
    width: 44%;
    background: var(--paper-2);
    clip-path: polygon(24% 0, 100% 0, 100% 100%, 0 100%);
    pointer-events: none;
  }
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, .88fr);
    gap: 52px;
  }
  .page-about .ab-body {
    grid-template-columns: var(--ab-rail-w) minmax(0, 1fr);
    gap: 60px;
    padding-bottom: 96px;
  }
  .page-about .ab-rail {
    display: block;
    position: sticky;
    top: calc(var(--hd-main-h) + 28px);
    align-self: start;
  }
  .page-about .ab-rail__cap {
    margin: 0 0 14px;
    font-size: 11px;
    letter-spacing: .14em;
    color: var(--graphite);
  }
  .page-about .ab-rail__list {
    position: relative;
    list-style: none;
    margin: 0;
    padding: 0;
  }
  .page-about .ab-rail__list::before {
    content: "";
    position: absolute;
    left: 3px;
    top: 8px;
    bottom: 8px;
    width: 1px;
    background: var(--line-2);
  }
  .page-about .ab-rail__item {
    position: relative;
    display: grid;
    grid-template-columns: 7px minmax(0, 1fr);
    align-items: center;
    gap: 12px;
    padding: 11px 0;
    font-size: var(--fs-12);
    color: var(--graphite);
  }
  .page-about .ab-rail__item i {
    display: block;
    width: 7px;
    height: 7px;
    background: var(--paper-2);
    border: 1px solid var(--line-2);
  }
  .page-about .ab-rail__item.is-done i {
    background: var(--teal);
    border-color: var(--teal);
  }
  .page-about .ab-rail__item.is-now i {
    background: var(--orange);
    border-color: var(--orange);
    box-shadow: 0 0 0 4px rgba(255, 107, 26, .18);
  }
  .page-about .ab-rail__item.is-now span {
    color: var(--char);
    font-weight: 600;
  }
  .page-about .ab-rail__note {
    margin: 16px 0 0;
    padding-top: 14px;
    border-top: 1px solid var(--line);
    font-size: 11px;
    letter-spacing: .1em;
    color: var(--graphite);
  }
  .page-about .ab-team {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
    gap: 28px;
    align-items: start;
  }
  .page-about .ab-team__cards {
    grid-template-columns: minmax(0, 1fr);
  }
  .page-about .ab-partners {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .ab-pledge__list {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 30px;
  }
  .page-about .ab-pledge__item {
    padding-top: 0;
    border-top: 0;
    border-left: 1px solid var(--line-paper);
    padding-left: 22px;
  }
  .page-about .ab-pledge__item:first-child {
    border-left: 0;
    padding-left: 0;
  }
  .page-about .ab-chapters {
    gap: 88px;
  }
}