.page-about {
  background: var(--cream);
  color: var(--brown);
  font-family: var(--font-body);
  overflow-x: hidden;
}

.page-about .ab-crumbs {
  padding-top: 1.25rem;
  padding-bottom: 0.5rem;
}

.page-about .ab-img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 2px solid var(--line);
  background: var(--paper);
}

.page-about .ab-inline-link {
  color: var(--sand-deep);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 2px;
}

.page-about .ab-inline-link:hover {
  color: var(--ink);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  padding-bottom: 0;
  background:
    linear-gradient(180deg, var(--cream) 0%, var(--cream) 78%, var(--sand-light) 100%);
}

.page-about .ab-hero__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  padding-top: 1.5rem;
  padding-bottom: 3rem;
}

.page-about .ab-hero__title {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(2.2rem, 8.5vw, 4.6rem);
  line-height: 1.06;
  letter-spacing: -0.02em;
  color: var(--ink);
  margin: 0.9rem 0 0;
  overflow-wrap: break-word;
}

.page-about .ab-hero__lead {
  margin-top: 1.4rem;
  max-width: 36rem;
  font-size: 1.02rem;
  line-height: 1.85;
  color: var(--brown-soft);
}

.page-about .ab-hero__actions {
  margin-top: 1.9rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
}

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

.page-about .ab-hero__figure .ab-img {
  aspect-ratio: 4 / 5;
  box-shadow: var(--shadow-hard);
}

.page-about .ab-band {
  background: var(--ink);
  border-top: 2px solid var(--line);
  border-bottom: 2px solid var(--line);
}

.page-about .ab-band__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  padding-top: 1.9rem;
  padding-bottom: 1.9rem;
}

.page-about .ab-band__item {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  padding-left: 1rem;
  border-left: 3px solid var(--sand);
}

.page-about .ab-band__num {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--amber);
  line-height: 1;
}

.page-about .ab-band__label {
  font-size: 0.9rem;
  line-height: 1.7;
  color: var(--cream);
  opacity: 0.86;
}

/* ---------- 长卷正文与侧边索引 ---------- */
.page-about .ab-open__title,
.page-about .ab-timeline__title,
.page-about .ab-methods__title,
.page-about .ab-team__title,
.page-about .ab-value__title,
.page-about .ab-export__title {
  font-family: var(--font-head);
  font-weight: 800;
  color: var(--ink);
  font-size: clamp(1.55rem, 5vw, 2.35rem);
  line-height: 1.25;
  margin: 0.75rem 0 1.2rem;
  letter-spacing: -0.01em;
}

.page-about .ab-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.25rem;
}

.page-about .ab-open__prose {
  max-width: 44rem;
}

.page-about .ab-open__prose p {
  font-size: 1.03rem;
  line-height: 1.9;
  color: var(--brown-soft);
  margin-bottom: 1.15rem;
}

.page-about .ab-scenes {
  margin-top: 2.25rem;
  padding: 1.5rem 1.25rem;
  background: var(--paper);
  border: 2px solid var(--line);
  box-shadow: var(--shadow-hard);
}

.page-about .ab-scenes__title {
  font-family: var(--font-head);
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--ink);
  margin: 0 0 1.1rem;
  letter-spacing: 0.01em;
}

.page-about .ab-scenes__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.9rem;
}

.page-about .ab-scenes__item {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  padding-bottom: 0.85rem;
  border-bottom: 1px dashed var(--sand-light);
}

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

.page-about .ab-scenes__name {
  font-family: var(--font-head);
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--ink);
}

.page-about .ab-scenes__desc {
  font-size: 0.88rem;
  line-height: 1.7;
  color: var(--slate-deep);
}

.page-about .ab-pullquote {
  margin: 2.4rem 0 0;
  padding: 1.5rem 1.25rem;
  border: 2px solid var(--line);
  border-left: 10px solid var(--sand);
  background: var(--paper);
}

.page-about .ab-pullquote__text {
  font-family: var(--font-head);
  font-size: 1.15rem;
  font-weight: 700;
  line-height: 1.65;
  color: var(--ink);
  margin: 0;
}

.page-about .ab-layout__index {
  background: var(--paper);
  border: 2px solid var(--line);
  padding: 1.15rem 1.1rem;
}

.page-about .ab-layout__index .bc-index__title {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  color: var(--sand-deep);
  text-transform: uppercase;
  margin-bottom: 0.9rem;
}

.page-about .ab-layout__index .bc-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.15rem;
}

.page-about .ab-layout__index .bc-index__link {
  display: block;
  padding: 0.5rem 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--slate-deep);
  text-decoration: none;
  border-left: 3px solid transparent;
  transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}

.page-about .ab-layout__index .bc-index__link:hover,
.page-about .ab-layout__index .bc-index__link.is-active {
  background: var(--sand-light);
  border-left-color: var(--sand);
  color: var(--ink);
}

/* ---------- 时间轴 ---------- */
.page-about .ab-timeline {
  background: var(--cream);
  border-top: 2px solid var(--line);
  border-bottom: 2px solid var(--line);
}

.page-about .ab-timeline__head {
  max-width: 42rem;
}

.page-about .ab-nodes {
  list-style: none;
  margin: 2rem 0 0;
  padding: 0 0 0 1.6rem;
  position: relative;
}

.page-about .ab-nodes::before {
  content: "";
  position: absolute;
  left: 0.42rem;
  top: 0.6rem;
  bottom: 0.6rem;
  width: 2px;
  background: var(--ink);
  opacity: 0.45;
}

.page-about .ab-node {
  position: relative;
  padding: 0 0 2rem 0;
}

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

.page-about .ab-node__mark {
  position: absolute;
  left: -1.6rem;
  top: 0.25rem;
  width: 16px;
  height: 16px;
  color: var(--sand);
  background: var(--cream);
  display: flex;
  align-items: center;
  justify-content: center;
}

.page-about .ab-node--current .ab-node__mark {
  color: var(--sand-deep);
}

.page-about .ab-node__stage {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  color: var(--sand-deep);
  margin: 0 0 0.45rem;
}

.page-about .ab-node--current .ab-node__stage {
  display: inline-block;
  background: var(--ink);
  color: var(--amber);
  padding: 0.25rem 0.55rem;
  letter-spacing: 0.1em;
}

.page-about .ab-node__title {
  font-family: var(--font-head);
  font-size: 1.22rem;
  font-weight: 800;
  line-height: 1.4;
  color: var(--ink);
  margin: 0 0 0.7rem;
}

.page-about .ab-node__text {
  font-size: 0.98rem;
  line-height: 1.85;
  color: var(--brown-soft);
  margin: 0;
  max-width: 40rem;
}

.page-about .ab-node__link {
  display: inline-block;
  margin-top: 0.8rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--ink);
  text-decoration: none;
  border-bottom: 2px solid var(--sand);
  padding-bottom: 2px;
}

.page-about .ab-node__link:hover {
  color: var(--sand-deep);
  border-bottom-color: var(--ink);
}

.page-about .ab-timeline__figure {
  margin: 2.5rem 0 0;
}

.page-about .ab-timeline__figure .ab-img {
  aspect-ratio: 14 / 9;
  box-shadow: var(--shadow-hard);
}

.page-about .ab-timeline__figure .bc-figure__cap {
  margin-top: 0.8rem;
  font-size: 0.85rem;
  line-height: 1.7;
  color: var(--slate-deep);
}

/* ---------- 三条主线 ---------- */
.page-about .ab-methods__head {
  max-width: 44rem;
}

.page-about .ab-methods__list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  margin-top: 2rem;
}

.page-about .ab-method {
  background: var(--paper);
  border: 2px solid var(--line);
  box-shadow: var(--shadow-hard);
  padding: 1.35rem 1.2rem;
  display: grid;
  gap: 1rem;
}

.page-about .ab-method__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6rem;
}

.page-about .ab-method__head .bc-card__num {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--sand-deep);
  line-height: 1;
}

.page-about .ab-method__title {
  font-family: var(--font-head);
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--ink);
  margin: 0;
  flex: 1 1 auto;
}

.page-about .ab-method__text {
  font-size: 0.96rem;
  line-height: 1.85;
  color: var(--brown-soft);
  margin: 0;
}

.page-about .ab-method__more {
  margin-top: 0.9rem;
  border-top: 1px dashed var(--sand-light);
  padding-top: 0.7rem;
}

.page-about .ab-method__summary {
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  color: var(--celadon-deep);
  list-style: none;
}

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

.page-about .ab-method__summary::before {
  content: "＋ ";
  color: var(--sand);
}

.page-about .ab-method__more[open] .ab-method__summary::before {
  content: "－ ";
}

.page-about .ab-method__case {
  margin: 0.7rem 0 0;
  font-size: 0.9rem;
  line-height: 1.8;
  color: var(--slate-deep);
  background: var(--cream);
  border-left: 3px solid var(--celadon);
  padding: 0.7rem 0.85rem;
}

.page-about .ab-methods__path {
  margin: 2rem 0 0;
  font-size: 0.96rem;
  line-height: 1.85;
  color: var(--brown-soft);
}

/* ---------- 版本引用块 ---------- */
.page-about .ab-version {
  display: block;
  padding-top: 3rem;
  padding-bottom: 3rem;
}

.page-about .ab-version__inner {
  display: grid;
  gap: 1.25rem;
  justify-items: start;
}

.page-about .ab-version__kicker {
  color: var(--amber);
}

.page-about .ab-version__quote {
  margin: 0;
  padding: 1.4rem 1.2rem;
  border: 2px solid var(--amber);
  border-left: 10px solid var(--amber);
  background: transparent;
  max-width: 52rem;
}

.page-about .ab-version__quote p {
  margin: 0;
  font-family: var(--font-head);
  font-size: clamp(1.05rem, 3.6vw, 1.35rem);
  line-height: 1.7;
  font-weight: 600;
  color: var(--cream);
}

.page-about .ab-version__source {
  margin-top: 1rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  color: var(--amber);
}

.page-about .ab-version__link {
  justify-self: start;
}

/* ---------- 团队 ---------- */
.page-about .ab-team__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

.page-about .ab-team__lead {
  font-size: 1rem;
  line-height: 1.9;
  color: var(--brown-soft);
  max-width: 40rem;
}

.page-about .ab-team__duties {
  list-style: none;
  margin: 1.6rem 0 0;
  padding: 0;
  display: grid;
  gap: 0.85rem;
}

.page-about .ab-team__duty {
  font-size: 0.94rem;
  line-height: 1.8;
  color: var(--brown-soft);
  padding-left: 1rem;
  border-left: 3px solid var(--celadon);
}

.page-about .ab-team__duty strong {
  font-family: var(--font-head);
  color: var(--ink);
  margin-right: 0.35rem;
}

.page-about .ab-team__figure {
  margin: 0 0 1.5rem;
}

.page-about .ab-team__figure .ab-img {
  aspect-ratio: 3 / 2;
  box-shadow: var(--shadow-hard);
}

.page-about .ab-rhythm {
  background: var(--sand-light);
  border: 2px solid var(--line);
  padding: 1.25rem 1.15rem;
}

.page-about .ab-rhythm__title {
  font-family: var(--font-head);
  font-size: 1rem;
  font-weight: 800;
  color: var(--ink);
  margin: 0 0 1rem;
  letter-spacing: 0.02em;
}

.page-about .ab-rhythm__list {
  margin: 0;
  display: grid;
  gap: 0.7rem;
}

.page-about .ab-rhythm__row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px dashed rgba(43, 58, 69, 0.35);
}

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

.page-about .ab-rhythm__row dt {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  color: var(--ink);
}

.page-about .ab-rhythm__row dd {
  margin: 0;
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--brown);
  text-align: right;
}

/* ---------- 价值主张 ---------- */
.page-about .ab-value__head {
  max-width: 40rem;
}

.page-about .ab-value__grid {
  gap: 1.25rem;
  margin-top: 0.5rem;
}

.page-about .ab-value__item {
  padding: 1.35rem 1.15rem;
  background: var(--paper);
  border: 2px solid var(--line);
  border-top: 8px solid var(--ink);
}

.page-about .ab-value__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.16em;
  color: var(--sand-deep);
  margin-bottom: 0.6rem;
}

.page-about .ab-value__title-sm {
  font-family: var(--font-head);
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--ink);
  margin: 0 0 0.6rem;
}

.page-about .ab-value__text {
  margin: 0;
  font-size: 0.94rem;
  line-height: 1.85;
  color: var(--brown-soft);
}

.page-about .ab-value__close {
  margin: 1.8rem 0 0;
  font-size: 0.96rem;
  line-height: 1.85;
  color: var(--brown-soft);
  max-width: 46rem;
}

/* ---------- 页尾导出 ---------- */
.page-about .ab-export {
  background: var(--ink);
  border-top: 2px solid var(--line);
  padding-top: 2.6rem;
  padding-bottom: 2.6rem;
}

.page-about .ab-export__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.6rem;
  align-items: center;
}

.page-about .ab-export__kicker {
  color: var(--amber);
}

.page-about .ab-export__title {
  color: var(--cream);
  margin-bottom: 0.9rem;
}

.page-about .ab-export__desc {
  margin: 0;
  font-size: 0.96rem;
  line-height: 1.85;
  color: rgba(245, 238, 223, 0.85);
  max-width: 42rem;
}

.page-about .ab-export__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
}

.page-about .ab-export__actions .bc-btn--ghost {
  color: var(--cream);
  border-color: var(--cream);
}

.page-about .ab-export__actions .bc-btn--ghost:hover {
  background: var(--cream);
  color: var(--ink);
}

/* ---------- 渐进显现 ---------- */
.page-about [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.45s ease, transform 0.45s ease;
}

.page-about [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

.page-about [data-reveal="1"] { transition-delay: 0.06s; }
.page-about [data-reveal="2"] { transition-delay: 0.12s; }
.page-about [data-reveal="3"] { transition-delay: 0.18s; }

@media (prefers-reduced-motion: reduce) {
  .page-about [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .page-about .ab-layout__index .bc-index__link {
    transition: none;
  }
}

/* ---------- 平板及以上 ---------- */
@media (min-width: 640px) {
  .page-about .ab-band__inner {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1.75rem;
  }

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

  .page-about .ab-scenes__item:nth-last-child(2) {
    border-bottom: 0;
    padding-bottom: 0;
  }

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

  .page-about .ab-method:nth-child(3) {
    grid-column: 1 / -1;
  }

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

  .page-about .ab-value__item:nth-child(3) {
    grid-column: 1 / -1;
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 960px) {
  .page-about .ab-hero__inner {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    gap: 3.5rem;
    align-items: start;
    padding-top: 2.5rem;
    padding-bottom: 4rem;
  }

  .page-about .ab-hero__figure {
    margin-top: 1.25rem;
  }

  .page-about .ab-hero__figure .ab-img {
    aspect-ratio: 4 / 5;
  }

  .page-about .ab-layout {
    grid-template-columns: minmax(0, 1fr) 232px;
    gap: 3.5rem;
    align-items: start;
  }

  .page-about .ab-layout__index {
    order: 2;
    position: sticky;
    top: 96px;
  }

  .page-about .ab-open__prose {
    max-width: 42rem;
  }

  .page-about .ab-scenes {
    padding: 1.85rem 1.75rem;
  }

  .page-about .ab-pullquote {
    padding: 1.75rem 1.9rem;
    margin-right: -2rem;
  }

  .page-about .ab-nodes {
    padding-left: 8rem;
    margin-top: 3rem;
  }

  .page-about .ab-nodes::before {
    left: 6.85rem;
  }

  .page-about .ab-node {
    padding-bottom: 2.75rem;
  }

  .page-about .ab-node__mark {
    left: -8rem;
    top: 0.35rem;
  }

  .page-about .ab-node__stage {
    position: absolute;
    left: -8rem;
    top: 0.15rem;
    width: 6rem;
    text-align: right;
    margin: 0;
  }

  .page-about .ab-node--current .ab-node__stage {
    left: -8.6rem;
    width: 6.6rem;
    text-align: right;
  }

  .page-about .ab-node__text {
    max-width: 44rem;
  }

  .page-about .ab-timeline__figure {
    margin-top: 3.5rem;
    margin-left: 8rem;
  }

  .page-about .ab-methods__list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1.75rem;
    align-items: start;
  }

  .page-about .ab-method:nth-child(3) {
    grid-column: auto;
  }

  .page-about .ab-method:nth-child(2) {
    margin-top: 2.25rem;
  }

  .page-about .ab-method:nth-child(3) {
    margin-top: 1rem;
  }

  .page-about .ab-version {
    padding-top: 4rem;
    padding-bottom: 4rem;
  }

  .page-about .ab-version__quote {
    padding: 1.9rem 2.1rem;
    margin-left: 2rem;
  }

  .page-about .ab-team__inner {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.85fr);
    gap: 3.5rem;
    align-items: start;
  }

  .page-about .ab-team__side {
    margin-top: 2.5rem;
  }

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

  .page-about .ab-value__item:nth-child(3) {
    grid-column: auto;
  }

  .page-about .ab-value__item:nth-child(2) {
    margin-top: 1.75rem;
  }

  .page-about .ab-export__inner {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 0.65fr);
    gap: 2.5rem;
  }

  .page-about .ab-export__actions {
    justify-content: flex-end;
  }
}

@media (min-width: 1200px) {
  .page-about .ab-hero__title {
    font-size: clamp(3.4rem, 5.4vw, 4.9rem);
  }

  .page-about .ab-pullquote {
    margin-right: -4rem;
  }
}
<<<END>>>