.page-about {
  background: var(--c-paper);
  color: var(--c-char);
  font-family: var(--font-sans);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  display: flex;
  align-items: flex-end;
  min-height: clamp(520px, 82vh, 760px);
  overflow: hidden;
  background: var(--c-night);
}
.page-about .about-hero__img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 62%;
  z-index: 0;
}
.page-about .about-hero__scrim {
  position: absolute;
  inset: 0;
  z-index: 1;
  background:
    linear-gradient(180deg, rgba(14, 42, 36, .82) 0%, rgba(14, 42, 36, .26) 40%, rgba(14, 42, 36, .92) 100%);
}
.page-about .about-hero__inner {
  position: relative;
  z-index: 2;
  width: 100%;
  padding-top: clamp(56px, 10vw, 108px);
  padding-bottom: clamp(40px, 6vw, 80px);
  color: var(--c-paper);
}
.page-about .about-hero__crumb .breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 0 0 clamp(26px, 5vw, 54px);
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .08em;
}
.page-about .about-hero__crumb .breadcrumb__item {
  color: var(--paper-faint);
}
.page-about .about-hero__crumb .breadcrumb__item + .breadcrumb__item::before {
  content: "／";
  margin-right: 6px;
  color: var(--c-sand);
}
.page-about .about-hero__crumb .breadcrumb__link {
  color: var(--c-sand-soft);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}
.page-about .about-hero__crumb .breadcrumb__link:hover,
.page-about .about-hero__crumb .breadcrumb__link:focus-visible {
  color: var(--c-paper);
  border-bottom-color: var(--c-orange);
}
.page-about .about-hero__kicker {
  margin: 0 0 18px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--c-sand);
}
.page-about .about-hero__title {
  margin: 0;
  max-width: 15em;
  font-size: clamp(34px, 7.6vw, 88px);
  font-weight: 300;
  line-height: 1.08;
  letter-spacing: -.02em;
  color: var(--c-paper);
}
.page-about .about-hero__title em {
  display: inline-block;
  font-style: normal;
  font-weight: 700;
  color: var(--c-sand);
  transform: skewX(-6deg);
  transform-origin: left bottom;
}
.page-about .about-hero__lede {
  margin: clamp(20px, 3vw, 32px) 0 0;
  max-width: 34em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--paper-soft);
}
.page-about .about-hero__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 14px;
  margin: clamp(28px, 5vw, 48px) 0 0;
  padding: 0;
  list-style: none;
}
.page-about .about-hero__stat {
  border-top: 1px solid var(--hair-light);
  padding-top: 10px;
}
.page-about .about-hero__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(26px, 4vw, 40px);
  font-weight: 500;
  line-height: 1;
  letter-spacing: .02em;
  color: var(--c-sand);
}
.page-about .about-hero__stat-label {
  display: block;
  margin-top: 8px;
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--paper-faint);
}

/* ---------- 主体分栏 ---------- */
.page-about .about-body {
  padding-top: clamp(36px, 6vw, 84px);
  padding-bottom: clamp(56px, 8vw, 112px);
}
.page-about .about-rail-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 4vw, 56px);
}
.page-about .about-stream {
  min-width: 0;
}

/* ---------- 章节索引 ---------- */
.page-about .about-rail {
  position: sticky;
  top: 0;
  z-index: 6;
  background: var(--c-paper);
  border-bottom: 1px solid var(--hair);
  padding: 10px 0 12px;
}
.page-about .about-rail__title {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .2em;
  color: var(--c-slate);
}
.page-about .about-rail__list {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 2px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}
.page-about .about-rail__list::-webkit-scrollbar {
  display: none;
}
.page-about .about-rail__link {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  padding: 7px 10px;
  border: 1px solid var(--hair);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .06em;
  color: var(--ink-soft);
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--dur) var(--ease), background var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.page-about .about-rail__no {
  color: var(--c-slate);
  transition: color var(--dur) var(--ease);
}
.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  border-color: var(--c-sand);
  background: var(--c-sand-soft);
  color: var(--c-night);
}
.page-about .about-rail__link[data-active="true"] {
  border-color: var(--c-sand);
  background: var(--c-sand-soft);
  color: var(--c-night);
}
.page-about .about-rail__link[data-active="true"] .about-rail__no {
  color: var(--c-orange);
}

/* ---------- 章节通用 ---------- */
.page-about .about-chapter {
  padding: clamp(32px, 5vw, 68px) 0;
  border-top: 1px solid var(--hair);
}
.page-about .about-chapter:first-child {
  border-top: 0;
  padding-top: 0;
}
.page-about .about-chapter__eyebrow {
  display: inline-flex;
  align-items: baseline;
  gap: 10px;
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--c-forest);
}
.page-about .about-chapter__no {
  color: var(--c-orange);
  font-weight: 600;
}
.page-about .about-chapter__title {
  margin: 0 0 clamp(18px, 3vw, 30px);
  max-width: 20em;
  font-size: clamp(25px, 3.4vw, 44px);
  font-weight: 400;
  line-height: 1.2;
  letter-spacing: -.01em;
  color: var(--c-night);
}
.page-about .about-chapter__eyebrow--light {
  color: var(--c-sand);
}
.page-about .about-chapter__title--light {
  color: var(--c-paper);
}

.page-about .about-prose p {
  max-width: 38em;
  margin: 0 0 1.1em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-char);
}
.page-about .about-prose p:last-child {
  margin-bottom: 0;
}

/* ---------- 引言 ---------- */
.page-about .about-quote {
  margin: clamp(24px, 4vw, 40px) 0 0;
  padding: clamp(20px, 3vw, 34px) clamp(18px, 3vw, 32px);
  background: var(--c-sand-soft);
  border-left: 3px solid var(--c-orange);
  clip-path: var(--cut-tr);
}
.page-about .about-quote p {
  margin: 0;
  max-width: 26em;
  font-size: clamp(19px, 2.6vw, 27px);
  font-weight: 500;
  line-height: 1.55;
  letter-spacing: -.01em;
  color: var(--c-night);
}

/* ---------- 双面板 ---------- */
.page-about .about-pair {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: clamp(24px, 4vw, 40px);
}
.page-about .about-panel {
  padding: clamp(20px, 3vw, 30px);
  clip-path: var(--cut-tr);
}
.page-about .about-panel--sand {
  background: var(--c-sand);
  color: var(--c-night);
}
.page-about .about-panel--ink {
  background: var(--c-night);
  color: var(--c-paper);
}
.page-about .about-panel__no {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .2em;
  opacity: .7;
}
.page-about .about-panel__title {
  margin: 0 0 6px;
  font-size: clamp(19px, 2.2vw, 24px);
  font-weight: 600;
  letter-spacing: -.01em;
}
.page-about .about-panel__meta {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .06em;
  padding-bottom: 12px;
  border-bottom: 1px solid currentColor;
  opacity: .78;
}
.page-about .about-panel__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  opacity: .92;
}

/* ---------- 数据表 ---------- */
.page-about .about-table-wrap {
  margin-top: clamp(22px, 3vw, 34px);
  overflow-x: auto;
}
.page-about .about-table {
  width: 100%;
  min-width: 400px;
  border-collapse: collapse;
  font-size: 13px;
  line-height: 1.7;
}
.page-about .about-table__caption {
  caption-side: top;
  text-align: left;
  padding-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .16em;
  color: var(--c-slate);
}
.page-about .about-table th,
.page-about .about-table td {
  padding: 11px 12px;
  text-align: left;
  vertical-align: top;
}
.page-about .about-table thead th {
  background: var(--c-slate);
  color: var(--c-paper);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .08em;
}
.page-about .about-table tbody th {
  font-weight: 600;
  color: var(--c-night);
  border-bottom: 1px solid var(--hair);
}
.page-about .about-table tbody td {
  border-bottom: 1px solid var(--hair);
  color: var(--ink-soft);
}
.page-about .about-table tbody tr:nth-child(even) {
  background: rgba(220, 229, 234, .5);
}
.page-about .about-table .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 15px;
  color: var(--c-night);
  white-space: nowrap;
}

/* ---------- 折叠流程 ---------- */
.page-about .about-folds {
  margin-top: clamp(22px, 3vw, 34px);
  border-bottom: 1px solid var(--hair);
}
.page-about .about-fold {
  border-top: 1px solid var(--hair);
}
.page-about .about-fold summary {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px;
  padding: 15px 0;
  cursor: pointer;
  list-style: none;
  font-size: 15px;
  font-weight: 600;
  color: var(--c-night);
  transition: color var(--dur) var(--ease);
}
.page-about .about-fold summary::-webkit-details-marker {
  display: none;
}
.page-about .about-fold summary::after {
  content: "＋";
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--c-orange);
}
.page-about .about-fold[open] summary::after {
  content: "－";
}
.page-about .about-fold summary:hover,
.page-about .about-fold summary:focus-visible {
  color: var(--c-orange);
}
.page-about .about-fold__tag {
  margin-left: auto;
  padding: 3px 8px;
  background: var(--c-slate-soft);
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: .1em;
  color: var(--c-forest);
}
.page-about .about-fold__body {
  max-width: 40em;
  padding: 0 0 16px;
  font-size: 14px;
  line-height: 1.85;
  color: var(--ink-soft);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: clamp(26px, 4vw, 44px) 0 0;
}
.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  clip-path: var(--cut-tr);
  background: var(--c-slate-soft);
}
.page-about .about-figure__caption {
  margin: 10px 0 0;
  padding-left: 12px;
  border-left: 2px solid var(--c-sand);
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 1.7;
  color: var(--c-slate);
}

/* ---------- 里程碑 ---------- */
.page-about .about-milestones {
  padding: clamp(22px, 4vw, 46px);
  background: var(--c-night);
  clip-path: var(--cut-tr);
  color: var(--c-paper);
}
.page-about .about-axis {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  margin: clamp(14px, 2vw, 22px) 0 clamp(18px, 3vw, 28px);
}
.page-about .about-milestone-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--hair-light);
  border: 1px solid var(--hair-light);
}
.page-about .about-milestone {
  padding: 18px 16px 22px;
  background: var(--c-night);
  transition: background var(--dur) var(--ease);
}
.page-about .about-milestone:hover {
  background: var(--c-forest);
}
.page-about .about-milestone__when {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--c-sand);
}
.page-about .about-milestone__title {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 600;
  line-height: 1.4;
  color: var(--c-paper);
}
.page-about .about-milestone__text {
  margin: 0;
  font-size: 13px;
  line-height: 1.8;
  color: var(--paper-soft);
}

/* ---------- 运营地区 ---------- */
.page-about .about-region {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 40px);
  align-items: start;
}
.page-about .about-region__actions {
  margin: clamp(18px, 3vw, 26px) 0 0;
}
.page-about .about-figure--region {
  margin-top: 0;
}

/* ---------- 继续了解 ---------- */
.page-about .about-next {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin-top: clamp(32px, 5vw, 60px);
  background: var(--hair);
  border: 1px solid var(--hair);
}
.page-about .about-next__link {
  position: relative;
  display: block;
  padding: 18px 18px 20px;
  background: var(--c-paper);
  text-decoration: none;
  color: var(--c-char);
  border-left: 2px solid transparent;
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.page-about .about-next__link:hover,
.page-about .about-next__link:focus-visible {
  background: var(--c-sand-soft);
  border-left-color: var(--c-orange);
}
.page-about .about-next__label {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .18em;
  color: var(--c-slate);
}
.page-about .about-next__title {
  display: block;
  font-size: 15px;
  font-weight: 600;
  line-height: 1.5;
  color: var(--c-night);
}
.page-about .about-next__arrow {
  display: block;
  margin-top: 12px;
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--c-orange);
}

/* ---------- 焦点可见 ---------- */
.page-about a:focus-visible,
.page-about summary:focus-visible {
  outline: 2px solid var(--c-cyan);
  outline-offset: 3px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .about-milestone-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .about-next {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .about-pair {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-rail-layout {
    grid-template-columns: 176px minmax(0, 1fr);
    gap: clamp(40px, 5vw, 76px);
  }
  .page-about .about-rail {
    top: 96px;
    background: transparent;
    border-bottom: 0;
    border-left: 1px solid var(--hair);
    padding: 4px 0 4px 18px;
  }
  .page-about .about-rail__title {
    margin-bottom: 12px;
  }
  .page-about .about-rail__list {
    display: block;
    overflow: visible;
    margin-left: -20px;
  }
  .page-about .about-rail__item + .about-rail__item {
    margin-top: 2px;
  }
  .page-about .about-rail__link {
    display: flex;
    width: 100%;
    padding: 8px 10px 8px 18px;
    border: 0;
    border-left: 2px solid transparent;
    font-size: 12px;
    background: transparent;
  }
  .page-about .about-rail__link:hover,
  .page-about .about-rail__link:focus-visible {
    background: transparent;
    border-left-color: var(--c-sand);
    color: var(--c-night);
  }
  .page-about .about-rail__link[data-active="true"] {
    background: transparent;
    border-left-color: var(--c-orange);
    color: var(--c-night);
  }
  .page-about .about-chapter {
    padding: clamp(40px, 5vw, 76px) 0;
  }
  .page-about .about-region {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr);
    gap: clamp(28px, 4vw, 56px);
  }
}

@media (min-width: 1120px) {
  .page-about .about-milestone-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .about-rail-layout {
    grid-template-columns: 200px minmax(0, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-hero__title em {
    transform: none;
  }
  .page-about .about-next__link,
  .page-about .about-milestone,
  .page-about .about-rail__link,
  .page-about .about-fold summary {
    transition: none;
  }
}
<<<END>>>