.page-about {
  position: relative;
  background: var(--cream);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.85;
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  border-bottom: var(--bd);
  padding: 24px 0 40px;
}

.page-about .about-hero__texture {
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

.page-about .about-hero__texture img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.22;
  mix-blend-mode: multiply;
  max-width: 100%;
}

.page-about .about-hero > .wrap {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 22px 0 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--ochre);
}

.page-about .about-hero__eyebrow::before {
  content: "";
  flex: 0 0 auto;
  width: 38px;
  height: 2px;
  background: var(--ochre);
}

.page-about .about-hero h1 {
  margin: 0 0 20px;
  max-width: 20ch;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(32px, 6vw, 62px);
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.page-about .about-hero h1 em {
  font-style: normal;
  color: var(--ochre);
}

.page-about .about-hero__lead {
  margin: 0;
  max-width: 64ch;
  font-size: 16px;
  line-height: 1.9;
  color: var(--ink);
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
  border: var(--bd);
  background: var(--lake-light);
  box-shadow: var(--shadow-sm);
}

.page-about .about-stats li {
  background: var(--paper);
  padding: 14px 16px;
}

.page-about .about-stats b {
  display: block;
  font-family: var(--font-mono);
  font-size: 26px;
  font-weight: 700;
  line-height: 1.2;
  color: var(--ochre);
}

.page-about .about-stats span {
  display: block;
  margin-top: 4px;
  font-size: 13px;
  line-height: 1.5;
  color: var(--grey);
}

/* ---------- 分栏骨架 ---------- */
.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  padding-top: 36px;
  padding-bottom: 72px;
}

.page-about .about-shell > * {
  min-width: 0;
}

.page-about .about-rail {
  border-top: 1px solid var(--lake-light);
  border-bottom: 1px solid var(--lake-light);
  padding: 10px 0;
  margin-bottom: 36px;
}

.page-about .about-rail .toc__title {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--grey);
  text-transform: uppercase;
}

.page-about .about-rail .toc__list {
  display: flex;
  gap: 6px;
  margin: 0;
  padding: 0 0 4px;
  list-style: none;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-rail .toc__list > li {
  flex: 0 0 auto;
}

.page-about .toc__link {
  display: block;
  padding: 7px 12px;
  border: 1px solid var(--lake-light);
  font-size: 13.5px;
  line-height: 1.5;
  color: var(--grey);
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--t) var(--ease), border-color var(--t) var(--ease),
    background-color var(--t) var(--ease);
}

.page-about .toc__link .mono {
  margin-right: 6px;
  font-size: 11px;
  color: var(--ochre);
}

.page-about .toc__link:hover {
  color: var(--ink);
  border-color: var(--ink);
}

.page-about .toc__link[aria-current="true"] {
  color: var(--paper);
  background: var(--ochre);
  border-color: var(--ochre);
  font-weight: 700;
}

.page-about .toc__link[aria-current="true"] .mono {
  color: var(--paper);
}

/* ---------- 章节 ---------- */
.page-about .about-sec {
  scroll-margin-top: 84px;
}

.page-about .about-sec + .about-sec {
  margin-top: 56px;
  padding-top: 52px;
  border-top: 1px solid var(--lake-light);
}

.page-about .about-sec .section-head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin: 0 0 18px;
}

.page-about .about-sec .section-head__num {
  flex: 0 0 auto;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--ochre);
}

.page-about .about-sec .section-head__title {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(22px, 3.2vw, 34px);
  line-height: 1.28;
  letter-spacing: -0.01em;
}

.page-about .about-lead {
  margin: 0 0 24px;
  max-width: 66ch;
  font-size: 16px;
  line-height: 1.9;
  color: var(--ink);
}

.page-about .about-sub {
  margin: 32px 0 14px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 18px;
  line-height: 1.4;
}

/* ---------- 阶段卡 ---------- */
.page-about .about-stages {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}

.page-about .about-stage {
  display: flex;
  flex-direction: column;
  padding: 20px 18px 22px;
  background: var(--paper);
  border: var(--bd);
  box-shadow: var(--shadow-sm);
}

.page-about .about-stage__k {
  align-self: flex-start;
  margin-bottom: 14px;
  padding: 3px 9px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--paper);
  background: var(--ochre);
}

.page-about .about-stage:nth-child(2) .about-stage__k {
  background: var(--lake);
}

.page-about .about-stage:nth-child(3) .about-stage__k {
  background: var(--ochre-deep);
}

.page-about .about-stage h3 {
  margin: 0 0 10px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 18px;
  line-height: 1.45;
}

.page-about .about-stage p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--grey);
}

/* ---------- 图 ---------- */
.page-about .about-figure {
  margin: 26px 0 0;
  background: var(--paper);
  border: var(--bd);
  box-shadow: var(--shadow-sm);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .about-figure figcaption {
  padding: 9px 14px;
  border-top: 1px solid var(--lake-light);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--grey);
}

.page-about .about-figure--wide {
  margin-bottom: 26px;
}

/* ---------- 三层结构 ---------- */
.page-about .about-levels {
  margin: 0;
}

.page-about .about-lv {
  background: var(--paper);
  border: var(--bd);
  border-left: 6px solid var(--ochre);
  padding: 15px 15px 16px;
}

.page-about .about-lv + .about-lv,
.page-about .about-lv > .about-lv {
  margin-top: 14px;
}

.page-about .about-lv--2 {
  border-left-color: var(--lake);
}

.page-about .about-lv--3 {
  border-left-color: var(--gold);
  background: var(--cream);
}

.page-about .about-lv__head {
  margin: 0 0 6px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.45;
}

.page-about .about-lv__head .mono {
  margin-right: 8px;
  font-size: 19px;
  color: var(--ochre);
}

.page-about .about-lv--2 .about-lv__head .mono {
  color: var(--lake);
}

.page-about .about-lv--3 .about-lv__head .mono {
  color: var(--ochre-deep);
}

.page-about .about-lv__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--grey);
}

/* ---------- 查找示例 ---------- */
.page-about .about-example {
  margin-top: 24px;
  padding: 20px 20px 22px;
  background: var(--lake);
  color: var(--paper);
  border: var(--bd);
  box-shadow: var(--shadow);
}

.page-about .about-example__k {
  margin: 0 0 10px;
  font-size: 11.5px;
  letter-spacing: 0.14em;
  color: var(--paper);
  opacity: 0.8;
}

.page-about .about-example p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--paper);
}

/* ---------- 时间轴 ---------- */
.page-about .about-tl {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-tl__item {
  position: relative;
  padding: 0 0 24px 32px;
}

.page-about .about-tl__item::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 10px;
  bottom: 0;
  width: 2px;
  background: var(--lake-light);
}

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

.page-about .about-tl__item:last-child::before {
  display: none;
}

.page-about .about-tl__dot {
  position: absolute;
  left: 0;
  top: 6px;
  z-index: 1;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--cream);
  border: 3px solid var(--lake-light);
  box-sizing: content-box;
}

.page-about .about-tl__item.is-key .about-tl__dot {
  background: var(--gold);
  border-color: var(--gold);
  box-shadow: 0 0 0 3px rgba(201, 146, 43, 0.24);
}

.page-about .about-tl__ver {
  display: inline-block;
  margin-bottom: 9px;
  padding: 2px 9px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--paper);
  background: var(--ink);
}

.page-about .about-tl__item.is-key .about-tl__ver {
  background: var(--ochre);
}

.page-about .about-tl__card {
  padding: 15px 16px 17px;
  background: var(--paper);
  border: var(--bd);
  box-shadow: var(--shadow-sm);
  transition: transform var(--t) var(--ease), box-shadow var(--t) var(--ease);
}

.page-about .about-tl__item:hover .about-tl__card,
.page-about .about-tl__item:focus-within .about-tl__card {
  transform: translate(-2px, -2px);
  box-shadow: var(--shadow);
}

.page-about .about-tl__card h3 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.4;
}

.page-about .about-tl__card p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--grey);
}

.page-about .about-tl__points {
  display: grid;
  gap: 5px;
  margin: 12px 0 0;
  padding: 11px 0 0;
  list-style: none;
  border-top: 1px dashed var(--lake-light);
}

.page-about .about-tl__points li {
  position: relative;
  padding-left: 16px;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--ink);
}

.page-about .about-tl__points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.62em;
  width: 6px;
  height: 6px;
  background: var(--ochre);
  transform: rotate(45deg);
}

/* ---------- 编制条带 ---------- */
.page-about .about-crew {
  margin-top: 0;
  padding: 18px;
  background: var(--paper);
  border: var(--bd);
  box-shadow: var(--shadow-sm);
}

.page-about .about-crew__bar {
  display: flex;
  height: 58px;
  border: 2px solid var(--ink);
  overflow: hidden;
}

.page-about .about-crew__seg {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1px;
  color: var(--paper);
  font-family: var(--font-mono);
  transition: filter var(--t) var(--ease);
}

.page-about .about-crew__seg b {
  font-size: 17px;
  font-weight: 700;
  line-height: 1.1;
}

.page-about .about-crew__seg i {
  font-style: normal;
  font-size: 11px;
  letter-spacing: 0.04em;
  line-height: 1.3;
}

.page-about .about-crew__seg--edit {
  width: 58.3%;
  background: var(--ochre);
}

.page-about .about-crew__seg--maint {
  width: 25%;
  background: var(--lake);
}

.page-about .about-crew__seg--check {
  width: 16.7%;
  background: var(--ochre-deep);
}

.page-about .about-crew__seg:hover,
.page-about .about-crew__seg:focus-within {
  filter: brightness(1.12);
}

.page-about .about-crew__notes {
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 11px;
}

.page-about .about-crew__notes li {
  padding-left: 12px;
  border-left: 3px solid var(--lake-light);
  font-size: 14px;
  line-height: 1.8;
  color: var(--ink);
}

.page-about .about-crew__notes .mono {
  display: block;
  margin-bottom: 2px;
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--ochre);
}

/* ---------- 六项校验 ---------- */
.page-about .about-checks {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 1px;
  background: var(--lake-light);
  border: var(--bd);
}

.page-about .about-checks li {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 12px 14px;
  background: var(--paper);
  font-size: 14px;
  line-height: 1.75;
  color: var(--grey);
}

.page-about .about-checks .mono {
  flex: 0 0 auto;
  font-size: 11.5px;
  color: var(--ochre);
}

.page-about .about-checks b {
  flex: 0 0 auto;
  font-weight: 700;
  color: var(--ink);
}

/* ---------- 适配与归档 ---------- */
.page-about .about-twocol {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
}

.page-about .about-panel {
  padding: 22px 20px 20px;
  background: var(--paper);
  border: var(--bd);
  border-top: 6px solid var(--ochre);
  box-shadow: var(--shadow-sm);
}

.page-about .about-panel--lake {
  border-top-color: var(--lake);
}

.page-about .about-panel__num {
  display: block;
  margin-bottom: 4px;
  font-family: var(--font-mono);
  font-size: 40px;
  font-weight: 700;
  line-height: 1;
  color: var(--ochre);
}

.page-about .about-panel--lake .about-panel__num {
  color: var(--lake);
}

.page-about .about-panel h3 {
  margin: 0 0 12px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 18px;
  line-height: 1.4;
}

.page-about .about-panel p {
  margin: 0 0 12px;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--grey);
}

.page-about .about-panel__foot {
  margin: 0;
  padding-top: 10px;
  border-top: 1px dashed var(--lake-light);
  font-size: 12px;
  line-height: 1.7;
  color: var(--grey);
}

/* ---------- 共建 ---------- */
.page-about .about-cta {
  padding: 24px 20px 22px;
  background: var(--ink);
  color: var(--cream);
  border: var(--bd);
  box-shadow: var(--shadow);
}

.page-about .about-cta__k {
  margin: 0 0 12px;
  font-size: 11.5px;
  letter-spacing: 0.14em;
  color: var(--gold);
}

.page-about .about-cta__list {
  margin: 0 0 20px;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 10px;
}

.page-about .about-cta__list li {
  position: relative;
  padding-left: 18px;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--cream);
}

.page-about .about-cta__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.66em;
  width: 7px;
  height: 7px;
  background: var(--gold);
  transform: rotate(45deg);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-links {
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 1px;
  background: var(--lake-light);
  border: var(--bd);
}

.page-about .about-links li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 12px;
  padding: 12px 14px;
  background: var(--paper);
}

.page-about .about-links a {
  font-weight: 700;
  font-size: 14.5px;
  color: var(--ochre);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: border-color var(--t) var(--ease), color var(--t) var(--ease);
}

.page-about .about-links a:hover {
  color: var(--ochre-deep);
  border-bottom-color: var(--gold);
}

.page-about .about-links span {
  font-size: 13px;
  line-height: 1.7;
  color: var(--grey);
}

/* ---------- 平板 ---------- */
@media (min-width: 720px) {
  .page-about .about-hero {
    padding: 30px 0 48px;
  }

  .page-about .about-hero__lead {
    font-size: 17px;
  }

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

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

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

  .page-about .about-crew {
    padding: 22px;
  }

  .page-about .about-crew__bar {
    height: 64px;
  }

  .page-about .about-crew__seg b {
    font-size: 20px;
  }

  .page-about .about-crew__seg i {
    font-size: 12px;
  }

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

  .page-about .about-lv > .about-lv--2 {
    margin-left: 20px;
  }

  .page-about .about-lv--2 > .about-lv--3 {
    margin-left: 20px;
  }
}

/* ---------- 桌面：左侧目录 + 右侧长文 ---------- */
@media (min-width: 1000px) {
  .page-about .about-hero {
    padding: 34px 0 56px;
  }

  .page-about .about-shell {
    grid-template-columns: 246px minmax(0, 1fr);
    gap: 56px;
    padding-top: 52px;
    padding-bottom: 96px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 96px;
    align-self: start;
    margin-bottom: 0;
    padding: 0;
    border-top: 0;
    border-bottom: 0;
  }

  .page-about .about-rail .toc__title {
    margin-bottom: 12px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--ink);
  }

  .page-about .about-rail .toc__list {
    display: block;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-rail .toc__list > li + li {
    margin-top: 4px;
  }

  .page-about .toc__link {
    border: 0;
    border-left: 2px solid var(--lake-light);
    padding: 8px 14px;
  }

  .page-about .toc__link:hover {
    border-left-color: var(--gold);
  }

  .page-about .toc__link[aria-current="true"] {
    background: rgba(166, 62, 40, 0.08);
    border-left: 2px solid var(--ochre);
    color: var(--ink);
  }

  .page-about .toc__link[aria-current="true"] .mono {
    color: var(--ochre);
  }

  .page-about .about-lead {
    font-size: 16.5px;
  }

  .page-about .about-sec + .about-sec {
    margin-top: 72px;
    padding-top: 64px;
  }

  .page-about .about-tl__item {
    padding-left: 92px;
    padding-bottom: 28px;
  }

  .page-about .about-tl__item::before {
    left: 30px;
  }

  .page-about .about-tl__dot {
    left: 24px;
  }

  .page-about .about-tl__ver {
    position: absolute;
    left: 0;
    top: 2px;
    margin-bottom: 0;
  }

  .page-about .about-crew__notes {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
  }

  .page-about .about-cta {
    padding: 30px 28px 28px;
  }
}
<<<END>>>
```