.page-about {
  --about-line-w: 4px;
  --about-rail-w: 44px;
  --about-rail-a: var(--orange);
  --about-rail-b: var(--blue);
  background: var(--cloud);
  color: var(--fg);
  overflow-x: clip;
}

/* ============ 首屏 ============ */
.page-about .about-hero {
  position: relative;
  z-index: 0;
  display: grid;
  align-content: end;
  gap: clamp(2rem, 5vw, 3.5rem);
  min-height: min(82vh, 780px);
  padding-block: clamp(3rem, 8vw, 6rem) clamp(2.5rem, 6vw, 4.5rem);
  background: var(--navy);
  color: var(--cloud);
  overflow: hidden;
}

.page-about .about-hero__bg,
.page-about .about-hero__scrim {
  position: absolute;
  inset: 0;
  z-index: 0;
  width: 100%;
  height: 100%;
}

.page-about .about-hero__bg {
  object-fit: cover;
  object-position: center 40%;
  opacity: 0.5;
  max-width: none;
}

.page-about .about-hero__scrim {
  background:
    linear-gradient(112deg, rgba(7, 11, 24, 0.95) 0%, rgba(7, 11, 24, 0.82) 42%, rgba(30, 58, 138, 0.55) 100%);
}

.page-about .about-hero__inner,
.page-about .about-hero__preview {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__title {
  margin: 0.9rem 0 0;
  font-size: var(--fs-display);
  font-weight: 300;
  line-height: 1.04;
  letter-spacing: -0.02em;
  color: var(--cloud);
  max-width: 18ch;
}

.page-about .about-hero__lede {
  margin: 0;
  font-size: var(--fs-body);
  line-height: 1.85;
  color: rgba(245, 245, 245, 0.86);
  max-width: 46ch;
}

.page-about .about-hero__crumb {
  color: rgba(245, 245, 245, 0.6);
  font-size: 13px;
}

.page-about .about-hero__crumb .breadcrumb__item {
  color: inherit;
}

.page-about .about-hero__crumb a.breadcrumb__item {
  text-decoration: none;
  border-bottom: 1px solid rgba(245, 245, 245, 0.35);
  padding-bottom: 2px;
  transition: color 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .about-hero__crumb a.breadcrumb__item:hover,
.page-about .about-hero__crumb a.breadcrumb__item:focus-visible {
  color: var(--gold);
  border-color: var(--gold);
}

/* 章节预览 */
.page-about .about-hero__preview {
  display: grid;
  gap: 0.75rem;
}

.page-about .about-preview {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  border-top: 1px solid rgba(245, 245, 245, 0.22);
}

.page-about .about-preview a {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  padding: 0.8rem 0.25rem 0.8rem 0;
  font-size: 14px;
  line-height: 1.5;
  color: rgba(245, 245, 245, 0.9);
  text-decoration: none;
  border-bottom: 1px solid rgba(245, 245, 245, 0.14);
  transition: color 160ms var(--ease), transform 160ms var(--ease);
}

.page-about .about-preview a:hover,
.page-about .about-preview a:focus-visible {
  color: var(--orange);
  transform: translateX(4px);
}

.page-about .about-preview__num {
  flex: none;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  font-variant-numeric: tabular-nums;
  color: var(--gold);
}

/* ============ 长卷时间轴 ============ */
.page-about .about-timeline {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  padding-block: clamp(3rem, 7vw, 6rem) 0;
}

.page-about .about-chapter {
  display: grid;
  grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
  column-gap: clamp(1.1rem, 4vw, 2.5rem);
  padding-bottom: clamp(3rem, 7vw, 6rem);
  scroll-margin-top: 7rem;
}

.page-about .about-chapter__rail {
  position: relative;
  align-self: stretch;
}

.page-about .about-chapter__rail::after {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  right: 0;
  width: var(--about-line-w);
  background: linear-gradient(180deg, var(--about-rail-a), var(--about-rail-b));
}

.page-about .about-chapter__rail::before {
  content: "";
  position: absolute;
  top: 0.2rem;
  left: calc(100% - 2px);
  transform: translateX(-50%);
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--gold);
  border: 3px solid var(--ink);
  z-index: 2;
}

.page-about .about-chapter__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  font-variant-numeric: tabular-nums;
  color: var(--about-rail-a);
  padding-top: 0.3rem;
}

.page-about .about-chapter__body {
  min-width: 0;
}

.page-about .about-chapter__title {
  margin: 0.35rem 0 1.1rem;
  font-size: clamp(1.4rem, 2.6vw, 1.95rem);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .prose p {
  margin: 0 0 1rem;
  font-size: var(--fs-body);
  line-height: 1.85;
  color: var(--fg);
  max-width: 64ch;
}

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

.page-about .prose a {
  color: var(--orange-deep);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

.page-about .prose a:hover,
.page-about .prose a:focus-visible {
  color: var(--ink);
  background: var(--gold);
}

/* 章节色的冷热推进 */
.page-about .about-chapter:nth-of-type(1) { --about-rail-a: #FF6B00; --about-rail-b: #FF7A0F; }
.page-about .about-chapter:nth-of-type(2) { --about-rail-a: #FF7A0F; --about-rail-b: #E8701F; }
.page-about .about-chapter:nth-of-type(3) { --about-rail-a: #E8701F; --about-rail-b: #C1683A; }
.page-about .about-chapter:nth-of-type(4) { --about-rail-a: #C1683A; --about-rail-b: #8A5A5E; }
.page-about .about-chapter:nth-of-type(5) { --about-rail-a: #8A5A5E; --about-rail-b: #4E4A78; }
.page-about .about-chapter:nth-of-type(6) { --about-rail-a: #4E4A78; --about-rail-b: #2A4A8C; }
.page-about .about-chapter:nth-of-type(7) { --about-rail-a: #2A4A8C; --about-rail-b: #1E3A8A; }

.page-about .about-chapter:last-of-type {
  padding-bottom: clamp(2rem, 5vw, 4rem);
}

.page-about .about-chapter:last-of-type .about-chapter__rail::after {
  bottom: auto;
  height: 4rem;
}

/* 覆盖范围数字卡 */
.page-about .about-scope {
  list-style: none;
  margin: 1.75rem 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

.page-about .about-scope__item {
  display: grid;
  gap: 0.4rem;
  align-content: start;
  padding: 1.1rem 1rem;
  background: var(--cloud);
  border: var(--border) solid var(--ink);
  box-shadow: var(--shadow-hard-sm);
}

.page-about .about-scope__num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.75rem, 3.4vw, 2.4rem);
  line-height: 1;
  color: var(--orange);
}

.page-about .about-scope__label {
  font-size: 14px;
  line-height: 1.7;
  color: var(--fg-soft);
}

/* ============ 版本时间线 ============ */
.page-about .about-version__img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 2 / 1;
  object-fit: cover;
  margin: 1.5rem 0 2rem;
  border: var(--border) solid var(--ink);
  box-shadow: var(--shadow-hard);
}

.page-about .about-versions {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-version__box {
  border-bottom: 1px solid var(--line);
}

.page-about .about-version__sum {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  padding: 0.95rem 0;
  cursor: pointer;
  list-style: none;
  font-size: 15px;
  font-weight: 800;
  color: var(--ink);
}

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

.page-about .about-version__sum::marker {
  content: "";
}

.page-about .about-version__sum:focus-visible {
  outline: 3px solid var(--gold);
  outline-offset: 3px;
}

.page-about .about-version__tag {
  flex: none;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  font-variant-numeric: tabular-nums;
  color: var(--ink);
  background: var(--orange);
  border: 2px solid var(--ink);
  padding: 0.15rem 0.45rem;
  white-space: nowrap;
}

.page-about .about-version__hint {
  margin-left: auto;
  flex: none;
  width: 11px;
  height: 11px;
  border-right: 3px solid var(--orange-deep);
  border-bottom: 3px solid var(--orange-deep);
  transform: rotate(45deg) translate(-2px, -2px);
  transition: transform 200ms var(--ease);
}

.page-about .about-version__box[open] .about-version__hint {
  transform: rotate(-135deg) translate(-2px, -2px);
}

.page-about .about-version__desc {
  margin: 0 0 1.1rem;
  font-size: 15px;
  line-height: 1.8;
  color: var(--fg-soft);
  max-width: 62ch;
}

/* ============ 团队网格 ============ */
.page-about .about-team {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.15rem;
}

.page-about .about-team__item {
  display: grid;
  gap: 0.5rem;
  align-content: start;
  padding: 1.25rem 1.1rem;
  background: var(--cloud);
  border: var(--border) solid var(--ink);
  box-shadow: var(--shadow-hard-sm);
  transition: transform 160ms var(--ease), box-shadow 160ms var(--ease);
}

.page-about .about-team__item:hover {
  transform: translate(-4px, -4px);
  box-shadow: 10px 10px 0 var(--ink);
}

.page-about .about-team__mark {
  width: 14px;
  height: 14px;
  border: 2px solid var(--ink);
  transform: rotate(45deg);
}

.page-about .about-team__mark--edit { background: var(--orange); }
.page-about .about-team__mark--data { background: var(--blue); }
.page-about .about-team__mark--ux { background: var(--cyan); }
.page-about .about-team__mark--service { background: var(--orange-lift); }

.page-about .about-team__name {
  font-size: 1.1rem;
  font-weight: 800;
  color: var(--ink);
}

.page-about .about-team__count {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 1.45rem;
  line-height: 1;
  color: var(--blue);
}

.page-about .about-team__desc {
  font-size: 14px;
  line-height: 1.8;
  color: var(--fg-soft);
}

/* ============ 本地化服务 ============ */
.page-about .about-node-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  align-items: start;
}

.page-about .about-node-split img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border: var(--border) solid var(--ink);
  box-shadow: var(--shadow-hard);
}

.page-about .about-node-stat {
  margin-top: 1.75rem;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.1rem;
  padding: 1.35rem 1.2rem;
  background: linear-gradient(150deg, var(--blue-deep), var(--navy));
  border: var(--border) solid var(--ink);
  box-shadow: var(--shadow-hard);
  color: var(--cloud);
}

.page-about .about-node-stat__cell {
  display: grid;
  gap: 0.3rem;
  padding-left: 0.9rem;
  border-left: 4px solid var(--orange);
}

.page-about .about-node-stat__value {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.6rem, 3.4vw, 2.3rem);
  line-height: 1;
  color: var(--gold);
}

.page-about .about-node-stat__label {
  font-size: 13px;
  line-height: 1.6;
  color: rgba(245, 245, 245, 0.78);
}

/* ============ 下一步 ============ */
.page-about .about-next {
  display: grid;
  gap: 0.8rem;
  padding-block: clamp(3rem, 7vw, 5.5rem) clamp(4rem, 9vw, 7rem);
  border-top: 8px solid var(--orange);
}

.page-about .about-next__title {
  margin: 0 0 0.6rem;
  font-size: clamp(1.4rem, 2.6vw, 1.95rem);
  font-weight: 800;
  line-height: 1.25;
  color: var(--ink);
}

.page-about .about-next__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}

.page-about .about-next__list a {
  display: grid;
  gap: 0.35rem;
  padding: 1.1rem 0.25rem 1.1rem 0;
  text-decoration: none;
  color: var(--ink);
  border-bottom: 1px solid var(--line);
  transition: transform 160ms var(--ease), color 160ms var(--ease);
}

.page-about .about-next__list a:hover,
.page-about .about-next__list a:focus-visible {
  transform: translateX(6px);
  color: var(--orange-deep);
}

.page-about .about-next__name {
  font-size: 1.05rem;
  font-weight: 800;
}

.page-about .about-next__desc {
  font-size: 14px;
  line-height: 1.7;
  color: var(--fg-soft);
}

/* ============ 响应式 ============ */
@media (min-width: 620px) {
  .page-about .about-scope {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-preview {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 1.5rem;
  }

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

@media (min-width: 760px) {
  .page-about .about-team {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-next__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 2rem;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__inner {
    display: grid;
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    column-gap: clamp(2rem, 5vw, 5rem);
    align-items: end;
  }

  .page-about .about-hero__crumb {
    grid-column: 1 / -1;
  }

  .page-about .about-hero__title {
    grid-column: 1;
  }

  .page-about .about-hero__lede {
    grid-column: 2;
    padding-bottom: 0.4rem;
  }

  .page-about .about-chapter {
    grid-template-columns: minmax(0, 26%) minmax(0, 1fr);
    column-gap: clamp(2rem, 5vw, 5rem);
  }

  .page-about .about-node-split {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.85fr);
    gap: 2.5rem;
  }
}

@media (min-width: 1100px) {
  .page-about .about-preview {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (prefers-reduced-motion: reduce) {
  .page-about .about-preview a,
  .page-about .about-team__item,
  .page-about .about-next__list a,
  .page-about .about-version__hint {
    transition-duration: 1ms;
  }

  .page-about .about-preview a:hover,
  .page-about .about-preview a:focus-visible,
  .page-about .about-next__list a:hover,
  .page-about .about-next__list a:focus-visible {
    transform: none;
  }

  .page-about .about-team__item:hover {
    transform: none;
    box-shadow: var(--shadow-hard-sm);
  }
}