.page-about {
  --about-rail: 152px;
  --about-note: 250px;
  --about-onpine: #F3E9DC;
  --about-onpine-soft: rgba(246, 239, 228, 0.74);
  --about-onpine-line: rgba(246, 239, 228, 0.22);
  --about-shadow-card: 4px 4px 0 var(--laterite-900);

  background: var(--sand-050);
  color: var(--ink-900);
  font-family: var(--font-body);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

.page-about .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

.page-about p {
  margin: 0 0 1.05em;
}

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

.page-about a {
  color: var(--laterite-500);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

.page-about a:hover {
  color: var(--mineral-600);
  text-decoration-thickness: 2px;
}

/* ---------- 外壳 ---------- */
.page-about .about-shell {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  background: var(--sand-050);
  border-bottom: 3px solid var(--laterite-700);
  padding-block: clamp(34px, 6vw, 78px) clamp(38px, 7vw, 86px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  left: -6%;
  bottom: -34%;
  width: 62%;
  height: 62%;
  background: var(--laterite-700);
  opacity: 0.07;
  transform: rotate(-11deg);
  pointer-events: none;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  top: -90px;
  right: -70px;
  width: 240px;
  height: 420px;
  background: var(--pine-900);
  opacity: 0.07;
  transform: rotate(19deg);
  pointer-events: none;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.page-about .breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  list-style: none;
  margin: 0 0 22px;
  padding: 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.02em;
  color: var(--ink-500);
}

.page-about .breadcrumb__link {
  color: var(--ink-500);
  text-decoration: none;
  border-bottom: 1px solid var(--laterite-200);
}

.page-about .breadcrumb__link:hover {
  color: var(--mineral-600);
  border-bottom-color: var(--mineral-600);
}

.page-about .breadcrumb__sep {
  color: var(--laterite-200);
}

.page-about .about-hero .eyebrow {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--laterite-500);
}

.page-about .about-hero__title {
  margin: 0 0 22px;
  max-width: 18ch;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(30px, 6.2vw, 62px);
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--ink-900);
}

.page-about .about-hero__lede {
  max-width: 62ch;
  font-family: var(--font-serif);
  font-size: clamp(15.5px, 1.6vw, 18px);
  line-height: 1.85;
  color: var(--ink-900);
  margin-bottom: 30px;
}

.page-about .about-stamp {
  display: inline-block;
  max-width: 100%;
  border: 2px solid var(--mineral-600);
  border-radius: var(--radius);
  padding: 14px 20px 16px;
  background: rgba(246, 239, 228, 0.7);
}

.page-about .about-stamp__label {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--mineral-600);
}

.page-about .about-stamp__value {
  margin: 0 0 6px;
  font-size: clamp(15px, 2.2vw, 20px);
  font-weight: 700;
  color: var(--mineral-600);
  word-break: break-all;
}

.page-about .about-stamp__meta {
  margin: 0;
  font-size: 13px;
  color: var(--ink-500);
}

/* ---------- 分区与章节 ---------- */
.page-about .band {
  height: 10px;
  background: var(--laterite-700);
}

.page-about .band--pine {
  background: var(--pine-900);
}

.page-about .band--sand {
  background: var(--laterite-200);
  height: 8px;
}

.page-about .band--thick {
  height: 14px;
}

.page-about .band--laterite {
  background: var(--laterite-900);
}

.page-about .about-sec {
  padding-block: clamp(46px, 6vw, 96px);
}

.page-about .about-sec--sand {
  background: var(--sand-050);
}

.page-about .about-sec--paper {
  background: var(--sand-100);
}

.page-about .about-sec--pine {
  background: var(--pine-900);
  color: var(--about-onpine);
}

.page-about .about-sec--closing {
  background: var(--sand-050);
  border-top: 2px solid var(--laterite-200);
}

/* ---------- 网格骨架 ---------- */
.page-about .about-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
}

.page-about .about-sec__num {
  margin: 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  font-size: clamp(32px, 8vw, 46px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--laterite-700);
  border-top: 4px solid var(--laterite-700);
  padding-top: 8px;
  display: inline-block;
}

.page-about .about-sec--pine .about-sec__num {
  color: var(--pine-300);
  border-top-color: var(--pine-300);
}

.page-about .about-sec__title {
  margin: 0 0 16px;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(22px, 3.6vw, 34px);
  line-height: 1.32;
  letter-spacing: -0.005em;
  color: var(--ink-900);
}

.page-about .about-sec--pine .about-sec__title {
  color: var(--about-onpine);
}

.page-about .about-sec__lead {
  max-width: 60ch;
  font-family: var(--font-serif);
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.85;
  color: var(--ink-500);
  margin-bottom: 1.4em;
  padding-left: 14px;
  border-left: 3px solid var(--laterite-200);
}

.page-about .about-sec--pine .about-sec__lead--pine {
  color: var(--about-onpine-soft);
  border-left-color: var(--pine-300);
}

.page-about .about-sec__body > p {
  max-width: 68ch;
}

.page-about .about-sec--pine .about-pine-text {
  max-width: 68ch;
  color: var(--about-onpine-soft);
}

.page-about .about-link-pine {
  color: var(--pine-300);
}

.page-about .about-link-pine:hover {
  color: var(--about-onpine);
}

.page-about .about-sub__title {
  margin: 34px 0 14px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(17px, 2.2vw, 21px);
  letter-spacing: -0.01em;
  color: var(--ink-900);
}

/* ---------- 事实清单 ---------- */
.page-about .fact-sheet {
  margin: 26px 0 28px;
  border: 2px solid var(--laterite-900);
  border-radius: var(--radius);
  background: var(--sand-100);
  box-shadow: var(--about-shadow-card);
  overflow: hidden;
}

.page-about .fact-sheet__row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2px;
  padding: 12px 16px;
  border-bottom: 1px solid var(--laterite-200);
}

.page-about .fact-sheet__row:last-child {
  border-bottom: 0;
}

.page-about .fact-sheet__key {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--laterite-500);
}

.page-about .fact-sheet__val {
  margin: 0;
  font-size: 14.5px;
  color: var(--ink-900);
  word-break: break-word;
}

/* ---------- 三层嵌套列表 ---------- */
.page-about .layer-tree {
  list-style: none;
  margin: 26px 0 28px;
  padding: 0 0 0 22px;
  border-left: 3px solid var(--laterite-200);
}

.page-about .layer-tree__node {
  position: relative;
  padding: 0 0 26px 0;
}

.page-about .layer-tree__node:last-child {
  padding-bottom: 0;
}

.page-about .layer-tree__node::before {
  content: "";
  position: absolute;
  left: -29px;
  top: 9px;
  width: 11px;
  height: 11px;
  background: var(--sand-100);
  border: 3px solid var(--pine-700);
}

.page-about .layer-tree__code {
  margin: 0 0 4px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.1em;
  color: var(--pine-700);
}

.page-about .layer-tree__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(16.5px, 2.1vw, 20px);
  letter-spacing: -0.01em;
  color: var(--ink-900);
}

.page-about .layer-tree__text {
  margin: 0 0 10px;
  max-width: 62ch;
  color: var(--ink-500);
  font-size: 15px;
}

.page-about .layer-tree__items {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .layer-tree__items li {
  position: relative;
  padding-left: 18px;
  margin-bottom: 5px;
  font-size: 14.5px;
  color: var(--ink-900);
}

.page-about .layer-tree__items li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.78em;
  width: 9px;
  height: 2px;
  background: var(--laterite-500);
}

/* ---------- 旁注与图片 ---------- */
.page-about .about-note {
  align-self: start;
}

.page-about .about-figure {
  margin: 26px 0;
  border: 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  border: 2px solid var(--laterite-900);
  border-radius: var(--radius);
  background: var(--sand-100);
}

.page-about .about-figure__cap {
  margin: 10px 0 0;
  padding-left: 12px;
  border-left: 2px solid var(--laterite-200);
  font-size: 13px;
  line-height: 1.7;
  color: var(--ink-500);
}

.page-about .about-figure--tall {
  margin-top: 0;
}

.page-about .about-figure--tall img {
  aspect-ratio: 3 / 4;
}

.page-about .about-figure--wide img {
  aspect-ratio: 16 / 9;
}

.page-about .about-figure--mid img {
  aspect-ratio: 3 / 2;
}

/* ---------- 规格分层表 ---------- */
.page-about .spec-tree {
  list-style: none;
  margin: 26px 0 26px;
  padding: 0;
  border-top: 2px solid var(--about-onpine-line);
  border-bottom: 2px solid var(--about-onpine-line);
}

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

.page-about .spec-tree__item:last-child {
  border-bottom: 0;
}

.page-about .spec-tree__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 14px;
  width: 100%;
  padding: 14px 10px;
  background: transparent;
  border: 0;
  border-left: 3px solid transparent;
  border-radius: 0;
  color: inherit;
  font: inherit;
  text-align: left;
  cursor: pointer;
  transition: background-color 180ms ease, border-left-color 180ms ease;
}

.page-about .spec-tree__head:hover,
.page-about .spec-tree__head:focus-visible {
  background: rgba(246, 239, 228, 0.07);
  border-left-color: var(--mineral-600);
  outline: none;
}

.page-about .spec-tree__code {
  flex: 0 0 auto;
  font-size: 12.5px;
  letter-spacing: 0.1em;
  color: var(--pine-300);
}

.page-about .spec-tree__name {
  flex: 1 1 8ch;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(15.5px, 2vw, 18px);
  letter-spacing: -0.005em;
  color: var(--about-onpine);
}

.page-about .spec-tree__count {
  flex: 0 0 auto;
  font-size: 13px;
  color: var(--about-onpine-soft);
}

.page-about .spec-tree__marker {
  flex: 0 0 auto;
  width: 22px;
  height: 22px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--about-onpine-line);
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1;
  color: var(--about-onpine);
  transition: transform 200ms ease, border-color 200ms ease;
}

.page-about .spec-tree__head[aria-expanded="true"] .spec-tree__marker {
  transform: rotate(45deg);
  border-color: var(--mineral-600);
  color: var(--pine-300);
}

.page-about .spec-tree__panel {
  padding: 2px 10px 18px 26px;
  border-left: 3px solid var(--pine-700);
}

.page-about .spec-tree__values {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .spec-tree__values li {
  position: relative;
  padding-left: 16px;
  margin-bottom: 5px;
  font-size: 14px;
  color: var(--about-onpine-soft);
}

.page-about .spec-tree__values li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.8em;
  width: 8px;
  height: 2px;
  background: var(--pine-300);
}

/* ---------- 时间轴 ---------- */
.page-about .timeline {
  position: relative;
  list-style: none;
  margin: 30px 0 26px;
  padding: 0;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 3px;
  background: var(--laterite-200);
}

.page-about .timeline__item {
  position: relative;
  padding-left: 44px;
  padding-bottom: 30px;
}

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

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  width: 15px;
  height: 15px;
  background: var(--laterite-500);
  border: 3px solid var(--sand-050);
  box-shadow: 0 0 0 2px var(--laterite-500);
}

.page-about .timeline__code {
  margin: 0 0 4px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.1em;
  color: var(--laterite-500);
}

.page-about .timeline__title {
  margin: 0 0 8px;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(17px, 2.3vw, 21px);
  line-height: 1.4;
  color: var(--ink-900);
}

.page-about .timeline__text {
  margin: 0;
  max-width: 64ch;
  font-size: 15px;
  color: var(--ink-500);
}

/* ---------- 维护分组 ---------- */
.page-about .crew-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
  margin: 26px 0 30px;
}

.page-about .crew {
  border: 2px solid var(--laterite-900);
  border-radius: var(--radius);
  background: var(--sand-050);
  box-shadow: var(--about-shadow-card);
  padding: 18px 18px 14px;
}

.page-about .crew__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 12px;
  margin-bottom: 10px;
}

.page-about .crew__code {
  flex: 0 0 100%;
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--laterite-500);
}

.page-about .crew__title {
  flex: 1 1 auto;
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(16px, 2.1vw, 19px);
  letter-spacing: -0.01em;
  color: var(--ink-900);
}

.page-about .crew__size {
  margin: 0;
  font-size: 13.5px;
  color: var(--pine-700);
}

.page-about .crew__text {
  margin: 0 0 14px;
  font-size: 14.5px;
  color: var(--ink-500);
}

.page-about .crew__toggle {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 8px 12px;
  border: 2px solid var(--laterite-900);
  border-radius: var(--radius);
  background: transparent;
  color: var(--laterite-900);
  font-family: var(--font-body);
  font-size: 13.5px;
  cursor: pointer;
  transition: background-color 180ms ease, color 180ms ease;
}

.page-about .crew__toggle:hover,
.page-about .crew__toggle:focus-visible {
  background: var(--laterite-900);
  color: var(--sand-050);
  outline: none;
}

.page-about .crew__marker {
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1;
  transition: transform 200ms ease;
}

.page-about .crew__toggle[aria-expanded="true"] .crew__marker {
  transform: rotate(45deg);
}

.page-about .crew__panel {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--laterite-200);
}

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

.page-about .crew__duties li {
  position: relative;
  padding-left: 16px;
  margin-bottom: 5px;
  font-size: 14px;
  color: var(--ink-900);
}

.page-about .crew__duties li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.8em;
  width: 8px;
  height: 2px;
  background: var(--pine-700);
}

/* ---------- 分组合计 ---------- */
.page-about .group-tally {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 2px;
  background: var(--laterite-900);
  border: 2px solid var(--laterite-900);
  border-radius: var(--radius);
}

.page-about .group-tally__cell {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 18px 12px;
  background: var(--sand-050);
}

.page-about .group-tally__num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  font-size: clamp(28px, 6vw, 44px);
  line-height: 1;
  color: var(--laterite-700);
}

.page-about .group-tally__label {
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--ink-500);
}

.page-about .group-tally__foot {
  margin: 12px 0 0;
  font-size: 13.5px;
  color: var(--ink-500);
}

/* ---------- 流程链 ---------- */
.page-about .flow {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  list-style: none;
  margin: 0 0 22px;
  padding: 0;
}

.page-about .flow__step {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 9px 14px;
  border: 2px solid var(--pine-700);
  border-radius: var(--radius);
  background: var(--sand-050);
  font-size: 14px;
  color: var(--ink-900);
}

.page-about .flow__num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 20px;
  height: 20px;
  background: var(--pine-700);
  color: var(--sand-050);
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1;
}

/* ---------- 边界声明 ---------- */
.page-about .boundary {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2px;
  margin: 26px 0 28px;
  background: var(--laterite-200);
  border: 2px solid var(--laterite-900);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .boundary__col {
  background: var(--sand-050);
  padding: 18px 16px 16px;
}

.page-about .boundary__title {
  margin: 0 0 12px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--laterite-700);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 15.5px;
  letter-spacing: -0.005em;
  color: var(--ink-900);
}

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

.page-about .boundary__list li {
  position: relative;
  padding-left: 16px;
  margin-bottom: 6px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--ink-500);
}

.page-about .boundary__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.82em;
  width: 8px;
  height: 2px;
  background: var(--laterite-500);
}

/* ---------- 平板 ---------- */
@media (min-width: 720px) {
  .page-about .fact-sheet__row {
    grid-template-columns: 148px minmax(0, 1fr);
    align-items: baseline;
    gap: 16px;
  }

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

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

/* ---------- 桌面 ---------- */
@media (min-width: 1000px) {
  .page-about .about-grid {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 34px 40px;
  }

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

  .page-about .about-sec__rail {
    padding-top: 4px;
  }

  .page-about .about-sec__num {
    font-size: clamp(52px, 6vw, 72px);
    border-top-width: 5px;
  }

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

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

  .page-about .about-figure--wide {
    margin-top: 34px;
  }
}

@media (min-width: 1240px) {
  .page-about .timeline__item {
    padding-bottom: 36px;
  }

  .page-about .about-sec__lead {
    margin-bottom: 1.6em;
  }
}

/* ---------- 降低动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .spec-tree__marker,
  .page-about .spec-tree__head,
  .page-about .crew__marker,
  .page-about .crew__toggle {
    transition: none !important;
  }

  .page-about .spec-tree__head[aria-expanded="true"] .spec-tree__marker,
  .page-about .crew__toggle[aria-expanded="true"] .crew__marker {
    transform: none;
  }
}