.page-about {
  --about-rail: 76px;
  --about-gap: clamp(20px, 3vw, 36px);
  background: var(--bp-900);
  color: var(--mist);
  overflow-x: clip;
  padding-bottom: clamp(64px, 9vw, 120px);
}

.page-about .breadcrumb {
  padding-top: clamp(20px, 3vw, 32px);
}

/* ---------- 框景主窗 ---------- */
.page-about .about-frame {
  position: relative;
  margin-top: 18px;
  padding: clamp(20px, 3.2vw, 40px);
  border: 1px solid var(--navy-line);
  background:
    linear-gradient(158deg, rgba(16, 41, 77, 0.72), rgba(5, 18, 31, 0) 64%),
    repeating-linear-gradient(90deg, rgba(29, 62, 107, 0.28) 0 1px, transparent 1px 32px);
}

.page-about .about-frame::before,
.page-about .about-frame::after {
  content: "";
  position: absolute;
  width: 16px;
  height: 16px;
  border: 1px solid var(--orange);
  pointer-events: none;
}

.page-about .about-frame::before {
  top: -1px;
  left: -1px;
  border-right: 0;
  border-bottom: 0;
}

.page-about .about-frame::after {
  right: -1px;
  bottom: -1px;
  border-top: 0;
  border-left: 0;
}

.page-about .about-frame__head {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 10px 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--navy-line);
}

.page-about .about-frame__code {
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--mist);
}

.page-about .about-frame__body {
  margin-top: clamp(24px, 4vw, 52px);
  gap: clamp(24px, 3vw, 40px);
  align-items: start;
}

.page-about .about-lede__title {
  margin: 0;
  font-size: clamp(1.9rem, 4.4vw, 3.5rem);
  font-weight: 300;
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--white);
  max-width: 20ch;
}

.page-about .about-lede__text {
  margin: 20px 0 0;
  max-width: 40ch;
  font-size: 17px;
  line-height: 1.75;
  color: var(--mist);
}

.page-about .about-lede__facts {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 30px;
  margin: 26px 0 0;
  padding: 14px 0;
  list-style: none;
  border-top: 1px solid var(--navy-line);
  border-bottom: 1px solid var(--navy-line);
  font-size: 13px;
  color: var(--mist);
}

.page-about .about-lede__facts .mono {
  margin-right: 6px;
  font-size: 15px;
  font-weight: 500;
  color: var(--orange);
}

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

.page-about .about-lede__figure {
  position: relative;
  margin: 0;
}

.page-about .about-lede__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border: 1px solid var(--navy-line);
  filter: saturate(0.86) contrast(1.04);
}

.page-about .about-lede__figure::after {
  content: "";
  position: absolute;
  right: -10px;
  bottom: -10px;
  width: 38%;
  height: 42%;
  border-right: 1px solid var(--orange);
  border-bottom: 1px solid var(--orange);
  pointer-events: none;
}

/* ---------- 章节骨架 ---------- */
.page-about .about-section {
  position: relative;
  display: grid;
  grid-template-columns: var(--about-rail) minmax(0, 1fr);
  gap: var(--about-gap);
  padding-block: clamp(48px, 7vw, 96px) 0;
}

.page-about .about-section__rail {
  position: sticky;
  top: 96px;
  align-self: start;
  padding-top: 4px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--orange);
}

.page-about .about-section__rail::after {
  content: "";
  display: block;
  width: 1px;
  height: 54px;
  margin-top: 12px;
  background: linear-gradient(var(--navy-line), transparent);
}

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

.page-about .about-crosslink {
  margin: 26px 0 0;
  padding-left: 16px;
  border-left: 1px solid var(--orange);
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--mist);
}

.page-about a {
  color: var(--orange-soft);
  text-decoration: none;
  border-bottom: 1px solid rgba(255, 154, 87, 0.42);
}

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

.page-about .btn {
  border-bottom: 0;
}

/* ---------- 01 起算刻度 ---------- */
.page-about .about-cols {
  display: grid;
  grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  gap: clamp(22px, 3vw, 44px);
  align-items: start;
}

.page-about .about-cols__main p {
  margin: 0 0 18px;
  max-width: 42ch;
  font-size: 17px;
  line-height: 1.78;
  color: var(--mist);
}

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

.page-about .about-metrics {
  margin: 0;
  padding: 4px 0 0;
  border-top: 1px solid var(--navy-line);
}

.page-about .about-metrics__row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 0;
  border-bottom: 1px solid var(--navy-line);
}

.page-about .about-metrics dt {
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--mist);
}

.page-about .about-metrics dd {
  margin: 0;
  font-size: 20px;
  font-weight: 500;
  color: var(--orange);
  font-variant-numeric: tabular-nums;
}

/* ---------- 02 栏目条带 ---------- */
.page-about .lane-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .lane {
  position: relative;
  display: grid;
  grid-template-columns: 52px minmax(0, 1fr);
  gap: 18px;
  padding: 20px 28px 20px 20px;
  background: linear-gradient(92deg, rgba(16, 41, 77, 0.95), rgba(10, 29, 51, 0.5));
  border-left: 2px solid var(--orange);
  clip-path: polygon(0 0, calc(100% - 16px) 0, 100% 16px, 100% 100%, 0 100%);
}

.page-about .lane:nth-child(1) { width: 100%; }
.page-about .lane:nth-child(2) { width: 94%; }
.page-about .lane:nth-child(3) { width: 88%; }
.page-about .lane:nth-child(4) { width: 82%; }
.page-about .lane:nth-child(5) { width: 76%; }

.page-about .lane__no {
  padding-top: 4px;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--orange);
}

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

.page-about .lane__title {
  margin: 0;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: 0.01em;
  color: var(--white);
}

.page-about .lane__text {
  margin: 8px 0 0;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.72;
  color: var(--mist);
}

.page-about .lane__link {
  display: inline-block;
  margin-top: 12px;
  padding-bottom: 2px;
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--lime);
  border-bottom: 1px solid rgba(199, 255, 79, 0.45);
}

.page-about .lane__link:hover,
.page-about .lane__link:focus-visible {
  color: var(--lime);
  border-bottom-color: var(--lime);
}

/* ---------- 03 统计边界 ---------- */
.page-about .scope-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(16px, 2.4vw, 24px);
}

.page-about .scope-col {
  padding: 22px 24px;
  background: var(--bp-800);
  border-top: 2px solid var(--navy-line);
  clip-path: polygon(0 0, calc(100% - 14px) 0, 100% 14px, 100% 100%, 0 100%);
}

.page-about .scope-col--in {
  border-top-color: var(--orange);
}

.page-about .scope-col__title {
  margin: 0 0 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.14em;
  color: var(--mist);
}

.page-about .scope-col--in .scope-col__title {
  color: var(--orange-soft);
}

.page-about .scope-col ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .scope-col li {
  position: relative;
  padding-left: 18px;
  margin-bottom: 12px;
  font-size: 15px;
  line-height: 1.72;
  color: var(--mist);
}

.page-about .scope-col li:last-child {
  margin-bottom: 0;
}

.page-about .scope-col li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 8px;
  height: 1px;
  background: var(--navy-line);
}

.page-about .scope-col--in li::before {
  background: var(--orange);
}

.page-about .about-note {
  margin: 26px 0 0;
  padding: 16px 20px;
  max-width: 68ch;
  border-left: 2px solid var(--lime);
  background: rgba(199, 255, 79, 0.06);
  font-size: 14px;
  line-height: 1.76;
  color: var(--mist);
}

/* ---------- 04 版本轴 ---------- */
.page-about .vtl {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .vtl::before {
  content: "";
  position: absolute;
  left: 13px;
  top: 16px;
  bottom: 20px;
  width: 1px;
  background: var(--navy-line);
}

.page-about .vtl__item {
  position: relative;
  padding-left: 50px;
  padding-bottom: 14px;
}

.page-about .vtl__node {
  position: absolute;
  left: 0;
  top: 16px;
  display: grid;
  place-items: center;
  width: 27px;
  height: 27px;
  border: 1px solid var(--navy-line);
  border-radius: 50%;
  background: var(--bp-900);
  font-size: 10px;
  letter-spacing: 0;
  color: var(--mist);
  transition: border-color 0.3s var(--ease), color 0.3s var(--ease);
}

.page-about .vtl__item:has(.vtl__panel[open]) .vtl__node {
  border-color: var(--orange);
  color: var(--orange);
}

.page-about .vtl__panel {
  background: var(--bp-800);
  border-left: 1px solid var(--navy-line);
  clip-path: polygon(0 0, calc(100% - 16px) 0, 100% 16px, 100% 100%, 0 100%);
  transition: border-color 0.3s var(--ease);
}

.page-about .vtl__panel[open] {
  border-left-color: var(--orange);
}

.page-about .vtl__summary {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 20px;
  padding: 18px 24px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .vtl__panel[open] .vtl__summary {
  border-bottom: 1px solid var(--navy-line);
}

.page-about .vtl__ver {
  font-size: 22px;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--orange);
}

.page-about .vtl__name {
  font-size: 16px;
  font-weight: 600;
  color: var(--white);
}

.page-about .vtl__hint {
  position: relative;
  display: grid;
  place-items: center;
  width: 22px;
  height: 22px;
  margin-left: auto;
  border: 1px solid var(--navy-line);
  color: var(--mist);
}

.page-about .vtl__hint::before {
  content: "";
  width: 9px;
  height: 1px;
  background: currentColor;
}

.page-about .vtl__hint::after {
  content: "";
  position: absolute;
  width: 1px;
  height: 9px;
  background: currentColor;
  transition: transform 0.32s var(--ease);
}

.page-about .vtl__panel[open] .vtl__hint::after {
  transform: scaleY(0);
}

.page-about .vtl__panel[open] .vtl__hint {
  border-color: var(--orange);
  color: var(--orange);
}

.page-about .vtl__body {
  padding: 4px 24px 22px;
}

.page-about .vtl__body p {
  margin: 14px 0 0;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.76;
  color: var(--mist);
}

/* ---------- 05 校对流程（浅色分区） ---------- */
.page-about .about-section--paper {
  isolation: isolate;
  padding-block: clamp(56px, 8vw, 104px);
}

.page-about .about-section--paper::before {
  content: "";
  position: absolute;
  inset: 0 -50vw;
  z-index: -1;
  background: var(--paper);
}

.page-about .about-section--paper .section-head__title {
  color: var(--ink);
}

.page-about .about-section--paper .section-head__note,
.page-about .about-section--paper .scope-col__title {
  color: var(--slate);
}

.page-about .about-section--paper .about-cols__main p {
  color: var(--ink);
}

.page-about .about-section--paper .about-cols {
  grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
}

.page-about .about-review__figure {
  margin: 0;
}

.page-about .about-review__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border: 1px solid rgba(86, 101, 122, 0.35);
}

.page-about .about-flow-wrap {
  margin-top: clamp(28px, 4vw, 44px);
  overflow-x: auto;
}

.page-about .about-flow {
  display: block;
  width: 100%;
  min-width: 560px;
  height: auto;
}

.page-about .about-review__caption {
  margin: 18px 0 0;
  max-width: 62ch;
  font-size: 14px;
  line-height: 1.76;
  color: var(--slate);
}

.page-about .about-section--paper a {
  color: var(--ink);
  border-bottom-color: rgba(22, 32, 46, 0.35);
}

.page-about .about-section--paper a:hover,
.page-about .about-section--paper a:focus-visible {
  color: var(--orange);
  border-bottom-color: var(--orange);
}

/* ---------- 06 地方协作 ---------- */
.page-about .about-network {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(220px, 330px);
  gap: clamp(24px, 3.4vw, 48px);
  align-items: start;
}

.page-about .about-network__main p {
  margin: 0 0 18px;
  max-width: 46ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--mist);
}

.page-about .about-network__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-network__tags li {
  padding: 6px 13px;
  border: 1px solid var(--navy-line);
  background: var(--bp-800);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--mist);
}

.page-about .about-network__tags li.is-accent {
  border-color: rgba(255, 107, 26, 0.6);
  color: var(--orange-soft);
  background: rgba(255, 107, 26, 0.08);
}

.page-about .about-network__figure {
  position: relative;
  margin: 0;
}

.page-about .about-network__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  border: 1px solid var(--navy-line);
  filter: saturate(0.82) contrast(1.06);
}

.page-about .about-network__figure::before {
  content: "";
  position: absolute;
  top: -8px;
  left: -8px;
  width: 44px;
  height: 1px;
  background: var(--lime);
  pointer-events: none;
}

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .page-about {
    --about-rail: 44px;
  }

  .page-about .about-section {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 16px;
  }

  .page-about .about-section__rail {
    position: static;
    font-size: 11px;
  }

  .page-about .about-section__rail::after {
    height: 32px;
  }

  .page-about .about-cols,
  .page-about .about-section--paper .about-cols {
    grid-template-columns: minmax(0, 1fr);
  }

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

  .page-about .lane:nth-child(1),
  .page-about .lane:nth-child(2),
  .page-about .lane:nth-child(3),
  .page-about .lane:nth-child(4),
  .page-about .lane:nth-child(5) {
    width: 100%;
  }

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

  .page-about .about-network__figure {
    max-width: 380px;
  }

  .page-about .about-cols__main p,
  .page-about .about-network__main p {
    max-width: none;
  }
}

@media (max-width: 560px) {
  .page-about .about-frame__body {
    margin-top: 22px;
  }

  .page-about .about-lede__title {
    font-size: clamp(1.7rem, 8vw, 2.3rem);
    max-width: none;
  }

  .page-about .about-lede__facts {
    gap: 8px 18px;
  }

  .page-about .lane {
    grid-template-columns: 34px minmax(0, 1fr);
    gap: 12px;
    padding: 18px 20px 18px 14px;
  }

  .page-about .vtl__item {
    padding-left: 38px;
  }

  .page-about .vtl__summary,
  .page-about .vtl__body {
    padding-left: 16px;
    padding-right: 16px;
  }

  .page-about .about-section--paper::before {
    inset: 0 -24px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .vtl__node,
  .page-about .vtl__panel,
  .page-about .vtl__hint::after {
    transition: none;
  }
}