.page-about {
  --about-text: #C6CEC8;
  display: block;
  background: var(--c-asphalt);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding-block: clamp(20px, 3.6vw, 42px) clamp(26px, 4.4vw, 56px);
  border-bottom: 1px solid var(--c-line);
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  top: -34%;
  right: -12%;
  width: 46%;
  height: 170%;
  background: linear-gradient(135deg, rgba(200, 255, 46, 0.10), rgba(200, 255, 46, 0) 62%);
  transform: rotate(12deg);
  pointer-events: none;
}

.page-about .about-hero .crumb {
  position: relative;
  z-index: 1;
  margin-bottom: clamp(18px, 2.6vw, 30px);
}

.page-about .about-hero__title {
  position: relative;
  z-index: 1;
  max-width: 18ch;
  margin: 0 0 clamp(14px, 1.8vw, 22px);
  font-family: var(--font-display);
  font-style: italic;
  font-weight: 800;
  letter-spacing: 0.01em;
  color: var(--c-white);
}

.page-about .about-hero__lead {
  position: relative;
  z-index: 1;
  max-width: 62ch;
  margin: 0;
  color: var(--about-text);
  font-size: clamp(15px, 1.15vw, 17px);
  line-height: 1.65;
}

.page-about .about-hero__facts {
  position: relative;
  z-index: 1;
  list-style: none;
  margin: clamp(22px, 3vw, 36px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--c-line);
  border: 1px solid var(--c-line);
}

.page-about .about-fact {
  background: var(--c-graphite);
  padding: clamp(12px, 1.5vw, 18px) clamp(12px, 1.6vw, 20px);
}

.page-about .about-fact__num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(20px, 2.6vw, 30px);
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--c-neon);
}

.page-about .about-fact__label {
  display: block;
  margin-top: 6px;
  font-size: var(--fs-label);
  letter-spacing: 0.08em;
  color: var(--c-muted);
}

/* ---------- 章节锚点带 ---------- */
.page-about .about-toc {
  position: sticky;
  top: var(--header-h);
  z-index: 20;
  background: var(--c-asphalt);
  border-bottom: 1px solid var(--c-line);
}

.page-about .about-toc .toc__list {
  display: flex;
  margin: 0;
  padding: 0;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-toc .toc__list::-webkit-scrollbar {
  display: none;
}

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

.page-about .about-toc .toc__link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 12px clamp(12px, 1.6vw, 18px);
  border-right: 1px solid var(--c-line);
  color: var(--c-muted);
  font-size: 13px;
  white-space: nowrap;
  text-decoration: none;
  transition: color 0.24s var(--ease), background-color 0.24s var(--ease);
}

.page-about .about-toc .toc__idx {
  font-family: var(--font-mono);
  font-size: 11px;
  font-variant-numeric: tabular-nums;
  color: var(--c-neon-deep);
}

.page-about .about-toc .toc__link:hover {
  color: var(--c-white);
  background: var(--c-steel);
}

.page-about .about-toc .toc__link[aria-current="true"] {
  color: var(--c-neon);
  background: var(--c-graphite);
  box-shadow: inset 0 -2px 0 var(--c-neon);
}

/* ---------- 章节骨架 ---------- */
.page-about .about-chapter {
  padding-block: clamp(32px, 5vw, 66px);
  border-bottom: 1px solid var(--c-line);
}

.page-about .about-chapter__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(16px, 2.2vw, 26px);
}

.page-about .about-chapter__rail {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--c-line);
}

.page-about .about-chapter__num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(34px, 6vw, 56px);
  line-height: 1;
  letter-spacing: -0.03em;
  color: transparent;
  -webkit-text-stroke: 1.2px var(--c-neon);
}

.page-about .about-chapter__rail-label {
  font-size: var(--fs-label);
  letter-spacing: 0.14em;
  color: var(--c-muted);
}

.page-about .about-chapter__title {
  margin: 0 0 clamp(12px, 1.6vw, 18px);
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(24px, 3.4vw, 44px);
  line-height: 1.08;
  color: var(--c-white);
}

.page-about .about-chapter__body p {
  margin: 0 0 14px;
  max-width: 70ch;
  font-size: 15px;
  line-height: 1.65;
  color: var(--about-text);
}

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

/* ---------- 通用列表 ---------- */
.page-about .about-list {
  margin: 0 0 16px;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 10px;
  max-width: 74ch;
}

.page-about .about-list > li {
  position: relative;
  padding-left: 20px;
  font-size: 15px;
  line-height: 1.62;
  color: var(--about-text);
}

.page-about .about-list > li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.68em;
  width: 9px;
  height: 1px;
  background: var(--c-neon);
}

.page-about .about-list--muted > li::before {
  background: var(--c-muted);
}

.page-about .about-list--muted > li {
  color: var(--c-muted);
}

/* ---------- 图片容器 ---------- */
.page-about .about-banner {
  margin: 0 0 clamp(18px, 2.4vw, 30px);
  aspect-ratio: 8 / 3;
  border: 1px solid var(--c-line);
  overflow: hidden;
}

.page-about .about-banner img,
.page-about .about-shot img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.page-about .about-shot {
  margin: 0;
  aspect-ratio: 3 / 2;
  border: 1px solid var(--c-line);
  overflow: hidden;
}

.page-about .about-shot--wide {
  margin: clamp(20px, 2.8vw, 32px) 0 0;
}

/* ---------- 阶段时间轴 ---------- */
.page-about .about-stages {
  display: grid;
  gap: 1px;
  background: var(--c-line);
  border: 1px solid var(--c-line);
}

.page-about .about-stage {
  background: var(--c-graphite);
  padding: clamp(16px, 2.2vw, 26px);
}

.page-about .about-stage:nth-child(even) {
  background: var(--c-steel);
}

.page-about .about-stage__plate {
  display: inline-block;
  margin-bottom: 12px;
}

.page-about .about-stage__title {
  margin: 0 0 8px;
  font-size: clamp(17px, 1.6vw, 21px);
  line-height: 1.25;
  font-weight: 700;
  color: var(--c-white);
}

.page-about .about-stage p {
  margin: 0;
  max-width: 76ch;
  font-size: 15px;
  line-height: 1.62;
  color: var(--about-text);
}

/* ---------- 栏目映射 ---------- */
.page-about .about-map {
  margin: 0 0 clamp(22px, 3vw, 34px);
  padding: 0;
  list-style: none;
  display: grid;
  gap: 1px;
  background: var(--c-line);
  border: 1px solid var(--c-line);
}

.page-about .about-map__item {
  display: grid;
  gap: 8px;
  background: var(--c-graphite);
  padding: clamp(16px, 2vw, 22px);
}

.page-about .about-map__top {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.page-about .about-map__idx {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 12px;
  color: var(--c-neon-deep);
}

.page-about .about-map__link {
  color: var(--c-white);
  font-size: 17px;
  font-weight: 700;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.24s var(--ease), border-color 0.24s var(--ease);
}

.page-about .about-map__link:hover {
  color: var(--c-neon);
  border-bottom-color: var(--c-neon);
}

.page-about .about-map__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.62;
  color: var(--about-text);
}

.page-about .about-map__meta {
  color: var(--c-muted);
}

/* ---------- 小标题与分栏 ---------- */
.page-about .about-sub {
  margin: clamp(20px, 2.6vw, 30px) 0 10px;
  font-size: clamp(16px, 1.4vw, 19px);
  font-weight: 700;
  line-height: 1.3;
  color: var(--c-white);
}

.page-about .about-sub::before {
  content: "";
  display: inline-block;
  width: 14px;
  height: 1px;
  margin-right: 10px;
  vertical-align: middle;
  background: var(--c-neon);
}

.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(18px, 2.6vw, 34px);
}

.page-about .about-scope .about-sub {
  margin-top: 0;
}

/* ---------- 表格 ---------- */
.page-about .table-scroll {
  margin: 0 0 clamp(16px, 2vw, 24px);
  border: 1px solid var(--c-line);
  overflow-x: auto;
}

.page-about .data-table {
  width: 100%;
  min-width: 620px;
  border-collapse: collapse;
  font-size: 14px;
}

.page-about .about-table-cap {
  caption-side: top;
  text-align: left;
  padding: 12px 14px;
  color: var(--c-muted);
  border-bottom: 1px solid var(--c-line);
}

.page-about .data-table th,
.page-about .data-table td {
  padding: 11px 14px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--c-line);
}

.page-about .data-table thead th {
  font-size: 11px;
  letter-spacing: 0.08em;
  font-weight: 600;
  color: var(--c-muted);
  background: var(--c-steel);
}

.page-about .data-table tbody th {
  color: var(--c-white);
  font-weight: 700;
  white-space: nowrap;
}

.page-about .data-table tbody td {
  color: var(--about-text);
  line-height: 1.55;
}

.page-about .data-table tbody tr:nth-child(even) td,
.page-about .data-table tbody tr:nth-child(even) th {
  background: var(--c-steel);
}

.page-about .data-table .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 12.5px;
  color: var(--c-muted);
  white-space: normal;
}

/* ---------- 折叠面板 ---------- */
.page-about .about-fold {
  margin-top: clamp(16px, 2.2vw, 24px);
  border: 1px solid var(--c-line);
  background: var(--c-graphite);
}

.page-about .about-fold .fold__summary {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 14px 16px;
  cursor: pointer;
  list-style: none;
  font-weight: 600;
  font-size: 15px;
  color: var(--c-white);
}

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

.page-about .about-fold .fold__idx {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--c-neon-deep);
}

.page-about .about-fold .fold__body {
  padding: 0 16px 16px;
}

.page-about .about-fold .fold__body p {
  margin: 0;
  max-width: 76ch;
  font-size: 15px;
  line-height: 1.65;
  color: var(--about-text);
}

.page-about .about-fold[open] {
  border-color: var(--c-neon-deep);
}

/* ---------- 结尾动作 ---------- */
.page-about .about-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: clamp(22px, 3vw, 34px) 0 0 !important;
  padding-top: clamp(18px, 2.4vw, 26px);
  border-top: 1px solid var(--c-line);
}

/* ---------- 响应式 ---------- */
@media (min-width: 620px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 760px) {
  .page-about .about-stage {
    display: grid;
    grid-template-columns: 200px minmax(0, 1fr);
    column-gap: clamp(16px, 2.4vw, 32px);
    align-items: start;
  }

  .page-about .about-stage__plate {
    grid-column: 1;
    grid-row: 1 / span 2;
    margin-bottom: 0;
    justify-self: start;
  }

  .page-about .about-stage__title {
    grid-column: 2;
    grid-row: 1;
  }

  .page-about .about-stage p {
    grid-column: 2;
    grid-row: 2;
  }
}

@media (min-width: 860px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    align-items: start;
  }

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

@media (min-width: 900px) {
  .page-about .about-chapter__grid {
    grid-template-columns: 168px minmax(0, 1fr);
    column-gap: clamp(28px, 4vw, 60px);
  }

  .page-about .about-chapter__rail {
    position: sticky;
    top: calc(var(--header-h) + 96px);
    align-self: start;
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
    padding: 0 20px 0 0;
    border-bottom: 0;
    border-right: 1px solid var(--c-line);
  }

  .page-about .about-toc .toc__list {
    display: grid;
    grid-template-columns: repeat(6, minmax(0, 1fr));
    overflow: visible;
  }

  .page-about .about-toc .toc__list > li .toc__link {
    justify-content: flex-start;
    width: 100%;
  }

  .page-about .about-toc .toc__list > li:last-child .toc__link {
    border-right: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-toc .toc__link,
  .page-about .about-map__link {
    transition: none;
  }
}