.page-about {
  --about-index-w: 264px;
  --about-gap: 52px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-bottom: 48px;
}

.page-about .about-hero .breadcrumb {
  margin-bottom: 26px;
}

.page-about .about-hero__grid {
  display: grid;
  gap: 34px;
}

.page-about .about-hero h1 {
  font-family: var(--font-heading);
  font-size: clamp(31px, 7vw, 60px);
  line-height: 1.05;
  letter-spacing: -0.01em;
  color: var(--neutral-100);
  margin: 12px 0 18px;
}

.page-about .about-hero .lead {
  max-width: 58ch;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  align-content: start;
}

.page-about .about-fact {
  padding: 16px 14px;
  background: var(--ink-950);
  border: 4px solid var(--ink-700);
  box-shadow: var(--shadow-soft);
  min-width: 0;
}

.page-about .about-fact__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(22px, 4.4vw, 32px);
  line-height: 1.1;
  color: var(--amber-400);
  font-variant-numeric: tabular-nums;
  word-break: break-word;
}

.page-about .about-fact__label {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  line-height: 1.55;
  color: var(--neutral-400);
}

/* ---------- 主体分栏 ---------- */
.page-about .about-body {
  display: grid;
  gap: 26px;
}

.page-about .about-index__title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--neutral-400);
}

.page-about .about-index__list {
  list-style: none;
  display: flex;
  gap: 6px;
  margin: 0;
  padding: 0 0 8px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-index__link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  flex: 0 0 auto;
  padding: 10px 12px;
  border-bottom: 4px solid var(--ink-700);
  color: var(--neutral-400);
  text-decoration: none;
  font-size: 14px;
  white-space: nowrap;
  transition: color 160ms ease, border-color 160ms ease, background-color 160ms ease;
}

.page-about .about-index__num {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--cyan-400);
}

.page-about .about-index__link:hover {
  color: var(--cyan-200);
  border-color: var(--cyan-200);
}

.page-about .about-index__link[aria-current="true"] {
  color: var(--neutral-100);
  border-color: var(--cyan-400);
  background: var(--ink-800);
}

/* ---------- 长文画布 ---------- */
.page-about .about-canvas {
  display: grid;
  min-width: 0;
}

.page-about .about-chapter {
  padding: 30px 20px 34px;
  background: var(--ink-900);
  border-left: 4px solid var(--ink-700);
  scroll-margin-top: 132px;
}

.page-about .about-chapter + .about-chapter {
  margin-top: 6px;
}

.page-about .about-chapter:nth-child(even) {
  background: var(--ink-800);
  border-left-color: var(--cyan-400);
}

.page-about .about-chapter__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 14px;
  padding-bottom: 16px;
  margin-bottom: 22px;
  border-bottom: 1px solid var(--ink-700);
}

.page-about .about-chapter__num {
  font-family: var(--font-mono);
  font-size: clamp(26px, 5vw, 42px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--cyan-400);
  opacity: 0.4;
}

.page-about .about-chapter__title {
  flex: 1 1 220px;
  margin: 0;
  font-family: var(--font-heading);
  font-size: clamp(20px, 3.4vw, 30px);
  line-height: 1.22;
  letter-spacing: -0.01em;
  color: var(--neutral-100);
}

.page-about .about-chapter .prose {
  max-width: 68ch;
}

.page-about .about-chapter .prose p {
  margin: 0 0 16px;
  font-size: 16px;
  line-height: 1.78;
  color: var(--neutral-100);
}

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

.page-about .about-chapter .prose a {
  color: var(--cyan-400);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .about-chapter .prose a:hover {
  color: var(--cyan-200);
}

.page-about .term {
  color: var(--cyan-200);
  border-bottom: 1px dashed var(--cyan-400);
  cursor: help;
  text-decoration: none;
}

/* ---------- 原则条目 ---------- */
.page-about .about-principle__layout {
  display: grid;
  gap: 28px;
}

.page-about .about-principle {
  padding: 18px 0 18px 18px;
  border-left: 4px solid var(--cyan-400);
  border-bottom: 1px solid var(--ink-700);
}

.page-about .about-principle--b {
  border-left-color: var(--amber-400);
}

.page-about .about-principle--c {
  border-left-color: var(--cyan-200);
}

.page-about .about-principle__key {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-heading);
  font-size: 18px;
  letter-spacing: -0.01em;
  color: var(--neutral-100);
}

.page-about .about-principle__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--neutral-400);
}

/* ---------- 数据口径表 ---------- */
.page-about .about-fields {
  margin: 24px 0;
  border-top: 4px solid var(--ink-700);
}

.page-about .about-fields__row {
  display: grid;
  gap: 6px;
  padding: 16px 0;
  border-bottom: 1px solid var(--ink-700);
}

.page-about .about-fields dt {
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.02em;
  color: var(--amber-400);
}

.page-about .about-fields dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--neutral-400);
}

/* ---------- 时间线 ---------- */
.page-about .about-rail {
  display: flex;
  gap: 10px;
  margin: 24px 0 30px;
  padding: 4px 0 12px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-rail__node {
  flex: 0 0 auto;
  min-width: 122px;
  padding: 10px 12px;
  background: var(--ink-950);
  border: 4px solid var(--ink-700);
  color: var(--neutral-100);
  text-decoration: none;
  transition: border-color 160ms ease, transform 160ms ease;
}

.page-about .about-rail__node:hover {
  border-color: var(--cyan-400);
  transform: translateY(-2px);
}

.page-about .about-rail__year {
  display: block;
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--amber-400);
  font-variant-numeric: tabular-nums;
}

.page-about .about-rail__label {
  display: block;
  margin-top: 5px;
  font-size: 12px;
  color: var(--neutral-400);
}

.page-about .about-timeline {
  list-style: none;
  position: relative;
  margin: 0;
  padding: 0 0 0 30px;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(180deg, var(--cyan-400), var(--ink-700));
}

.page-about .about-timeline__item {
  position: relative;
  padding: 0 0 30px;
  scroll-margin-top: 132px;
}

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

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -30px;
  top: 7px;
  width: 14px;
  height: 14px;
  background: var(--ink-950);
  border: 3px solid var(--cyan-400);
}

.page-about .about-timeline__title {
  margin: 0 0 8px;
  font-family: var(--font-heading);
  font-size: 17px;
  line-height: 1.35;
  letter-spacing: -0.01em;
  color: var(--neutral-100);
}

.page-about .about-timeline__text {
  margin: 0;
  max-width: 66ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--neutral-400);
}

/* ---------- 团队花名册 ---------- */
.page-about .about-roster {
  list-style: none;
  display: grid;
  gap: 12px;
  margin: 26px 0 0;
  padding: 0;
}

.page-about .about-roster__item {
  padding: 16px;
  background: var(--ink-950);
  border: 4px solid var(--ink-700);
  box-shadow: var(--shadow-soft);
  min-width: 0;
}

.page-about .about-roster__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 30px;
  line-height: 1.1;
  color: var(--amber-400);
  font-variant-numeric: tabular-nums;
}

.page-about .about-roster__role {
  display: block;
  margin-top: 6px;
  font-family: var(--font-heading);
  font-size: 15px;
  color: var(--neutral-100);
}

.page-about .about-roster__desc {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  line-height: 1.65;
  color: var(--neutral-400);
}

/* ---------- 服务边界 ---------- */
.page-about .about-limits {
  list-style: none;
  margin: 0 0 24px;
  padding: 0;
  border-top: 1px solid var(--ink-700);
}

.page-about .about-limits__item {
  display: grid;
  gap: 8px;
  padding: 18px 0;
  border-bottom: 1px solid var(--ink-700);
}

.page-about .about-limits__mark {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--signal-500);
}

.page-about .about-limits__body {
  margin: 0;
  max-width: 66ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--neutral-100);
}

/* ---------- 收尾动线 ---------- */
.page-about .about-next {
  margin-top: 8px;
  padding: 28px 20px;
  background: var(--ink-950);
  border-left: 4px solid var(--cyan-400);
}

.page-about .about-next__title {
  margin: 10px 0 0;
  font-family: var(--font-heading);
  font-size: clamp(19px, 3vw, 26px);
  line-height: 1.25;
  letter-spacing: -0.01em;
  color: var(--neutral-100);
}

.page-about .about-next__list {
  list-style: none;
  display: grid;
  gap: 10px;
  margin: 22px 0 0;
  padding: 0;
}

.page-about .about-next__link {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: baseline;
  gap: 10px;
  padding: 14px 16px;
  border: 4px solid var(--ink-700);
  color: var(--neutral-100);
  text-decoration: none;
  font-family: var(--font-heading);
  font-size: 15px;
  transition: border-color 160ms ease, background-color 160ms ease, color 160ms ease;
}

.page-about .about-next__link:hover {
  border-color: var(--cyan-400);
  background: var(--ink-800);
  color: var(--cyan-200);
}

.page-about .about-next__hint {
  font-family: var(--font-body);
  font-weight: 400;
  font-size: 13px;
  color: var(--neutral-400);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 0 0 28px;
}

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

.page-about .img-frame.about-figure--square {
  aspect-ratio: 1 / 1;
}

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

.page-about .about-figure .img-frame__caption {
  font-size: 13px;
  line-height: 1.6;
  color: var(--neutral-400);
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-fields__row {
    grid-template-columns: 170px minmax(0, 1fr);
    gap: 22px;
    align-items: baseline;
  }

  .page-about .about-limits__item {
    grid-template-columns: 130px minmax(0, 1fr);
    gap: 22px;
  }

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

@media (min-width: 720px) {
  .page-about .about-roster {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-chapter {
    padding: 36px 32px 40px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    padding-bottom: 64px;
  }

  .page-about .about-hero__grid {
    grid-template-columns: 5fr 7fr;
    gap: 56px;
    align-items: start;
  }

  .page-about .about-principle__layout {
    grid-template-columns: minmax(0, 1fr) 280px;
    gap: 38px;
    align-items: start;
  }
}

@media (min-width: 1000px) {
  .page-about .about-body {
    grid-template-columns: var(--about-index-w) minmax(0, 1fr);
    gap: var(--about-gap);
  }

  .page-about .about-index__nav {
    position: sticky;
    top: 118px;
  }

  .page-about .about-index__list {
    display: block;
    overflow: visible;
    border-left: 4px solid var(--ink-700);
    padding: 0;
  }

  .page-about .about-index__link {
    border-bottom: none;
    border-left: 4px solid transparent;
    margin-left: -4px;
    white-space: normal;
    line-height: 1.45;
  }

  .page-about .about-index__link[aria-current="true"] {
    border-left-color: var(--cyan-400);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-index__link,
  .page-about .about-rail__node,
  .page-about .about-next__link {
    transition: none;
  }

  .page-about .about-rail__node:hover {
    transform: none;
  }
}
<<<END>>>