.page-about {
  --about-gap: clamp(48px, 8vw, 88px);
  --about-rail-w: 158px;
  --about-note-w: 248px;
  --contour: rgba(20, 33, 61, 0.24);
  background: var(--white);
  color: var(--ink);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding: 20px 0 0;
}

.page-about .about-hero .breadcrumbs {
  margin-bottom: 16px;
}

.page-about .about-hero__frame {
  position: relative;
  padding: clamp(20px, 5vw, 46px);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: linear-gradient(180deg, var(--white) 0%, var(--white) 58%, var(--mist) 100%);
  box-shadow: var(--shadow-stack);
}

.page-about .about-hero__frame::before,
.page-about .about-hero__frame::after {
  content: "";
  position: absolute;
  width: 16px;
  height: 16px;
  border: 1px solid var(--saffron);
  pointer-events: none;
}

.page-about .about-hero__frame::before {
  top: -1px;
  left: -1px;
  border-right-color: transparent;
  border-bottom-color: transparent;
}

.page-about .about-hero__frame::after {
  bottom: -1px;
  right: -1px;
  border-left-color: transparent;
  border-top-color: transparent;
}

.page-about .about-hero .page-head__title {
  margin: 14px 0 18px;
  max-width: 22ch;
  color: var(--indigo);
}

.page-about .about-hero__lead {
  max-width: 64ch;
  margin: 0;
  font-size: 16.5px;
  line-height: 1.85;
  color: var(--ink);
}

.page-about .about-hero__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 24px;
  margin: 26px 0 0;
  padding: 14px 0 0;
  border-top: 1px solid var(--line);
  list-style: none;
  font-size: 13.5px;
  color: var(--grey);
}

.page-about .about-hero__meta .mono {
  color: var(--indigo);
  font-weight: 700;
  margin-right: 4px;
}

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

.page-about .about-hero__banner {
  margin: clamp(20px, 4vw, 34px) 0 0;
  border-radius: var(--radius);
}

/* ---------- 主体骨架 ---------- */

.page-about .about-body {
  padding: var(--about-gap) 0 clamp(56px, 10vw, 120px);
}

.page-about .about-rail {
  margin: 0 0 24px;
  padding: 12px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-rail__label {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--grey);
}

.page-about .about-rail__list {
  display: flex;
  gap: 18px;
  margin: 0;
  padding: 0 0 4px;
  list-style: none;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}

.page-about .about-rail__link {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  white-space: nowrap;
  padding: 4px 0;
  font-size: 13.5px;
  color: var(--ink);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color 180ms var(--ease-panel), border-color 180ms var(--ease-panel);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--indigo);
  border-bottom-color: var(--saffron);
}

.page-about .about-rail__num {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--grey);
}

.page-about .about-flow > * + * {
  margin-top: var(--about-gap);
}

/* ---------- 章节 ---------- */

.page-about .about-chapter {
  scroll-margin-top: 96px;
}

.page-about .about-chapter > .section-title {
  position: relative;
  margin: 0 0 22px;
  padding-top: 16px;
  max-width: 26ch;
  color: var(--indigo);
}

.page-about .about-chapter > .section-title::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 42px;
  height: 2px;
  background: var(--saffron);
}

.page-about .about-chapter:target > .section-title::before {
  width: 84px;
  background: var(--indigo);
}

.page-about .about-chapter__body {
  display: block;
}

.page-about .about-chapter__main > *:first-child {
  margin-top: 0;
}

.page-about .about-chapter__main > *:last-child {
  margin-bottom: 0;
}

.page-about .about-chapter__main p {
  margin: 0 0 16px;
  font-size: 16px;
  line-height: 1.85;
  color: var(--ink);
}

.page-about .about-chapter__main strong {
  color: var(--indigo);
  font-weight: 700;
}

.page-about .about-chapter__main ul {
  margin: 18px 0;
  padding: 0 0 0 20px;
  list-style: none;
}

.page-about .about-chapter__main ul li {
  position: relative;
  margin: 0 0 12px;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--ink);
}

.page-about .about-chapter__main ul li::before {
  content: "";
  position: absolute;
  left: -18px;
  top: 12px;
  width: 8px;
  height: 1px;
  background: var(--saffron);
}

.page-about .about-chapter__note {
  margin: 20px 0 0;
  padding: 2px 0 2px 16px;
  border-left: 2px solid var(--amber);
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--indigo);
}

.page-about .about-chapter__note p {
  margin: 0;
}

.page-about .about-chapter__note .mono {
  font-weight: 700;
  color: var(--saffron);
}

.page-about .about-lead {
  margin: -6px 0 22px;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--grey);
}

.page-about .about-figure {
  margin: 28px 0 0;
  border-radius: var(--radius);
}

/* ---------- 时间线 ---------- */

.page-about .about-timeline {
  position: relative;
  margin: 0;
  padding: 4px 0 0;
  list-style: none;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 12px;
  bottom: 14px;
  width: 1px;
  background: var(--line-strong);
}

.page-about .about-timeline__item {
  position: relative;
  padding: 0 0 28px 32px;
}

.page-about .about-timeline__item:last-child {
  padding-bottom: 4px;
}

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: 1px;
  top: 6px;
  z-index: 1;
  width: 13px;
  height: 13px;
  border: 1px solid var(--indigo);
  border-radius: 3px;
  background: var(--white);
}

.page-about .about-timeline__item::after {
  content: "";
  position: absolute;
  left: 5px;
  top: 10px;
  z-index: 2;
  width: 5px;
  height: 5px;
  background: var(--saffron);
  transition: transform 240ms var(--ease-panel);
}

.page-about .about-timeline__item:hover::after {
  transform: scale(1.5);
}

.page-about .about-timeline__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  margin: 0 0 6px;
}

.page-about .about-timeline__phase {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--saffron);
}

.page-about .about-timeline__title {
  margin: 0;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--indigo);
}

.page-about .about-timeline__text {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--ink);
}

.page-about .about-timeline__text .mono {
  font-weight: 700;
  color: var(--indigo);
}

.page-about .about-timeline__more {
  margin: 20px 0 0;
  font-size: 14.5px;
}

/* ---------- 规模数据带 ---------- */

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0 0 26px;
  padding: 0;
  list-style: none;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-stats__cell {
  background: var(--white);
  padding: 22px 16px 20px;
}

.page-about .about-stats__value {
  display: block;
  font-size: clamp(26px, 5vw, 36px);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.01em;
  color: var(--indigo);
}

.page-about .about-stats__unit {
  margin-left: 3px;
  font-size: 0.5em;
  font-weight: 600;
  color: var(--saffron);
}

.page-about .about-stats__label {
  display: block;
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.55;
  color: var(--grey);
}

/* ---------- 等高线分隔 ---------- */

.page-about .about-contour {
  height: 44px;
  color: var(--contour);
}

.page-about .about-contour svg {
  display: block;
  width: 100%;
  height: 100%;
}

/* ---------- 承诺清单 ---------- */

.page-about .about-pledge li {
  padding-bottom: 4px;
}

/* ---------- 平板及以上 ---------- */

@media (min-width: 700px) {
  .page-about .about-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-hero__banner {
    margin-top: clamp(28px, 4vw, 40px);
  }
}

@media (min-width: 1000px) {
  .page-about .about-body {
    display: grid;
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    column-gap: clamp(40px, 5vw, 80px);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: 92px;
    margin: 0;
    padding: 4px 0 4px 18px;
    border-top: 0;
    border-bottom: 0;
    border-left: 1px solid var(--line);
  }

  .page-about .about-rail__list {
    flex-direction: column;
    gap: 2px;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-rail__link {
    display: flex;
    width: 100%;
    margin-left: -19px;
    padding: 9px 8px 9px 17px;
    border-bottom: 0;
    border-left: 2px solid transparent;
    transition: background 180ms var(--ease-panel), border-color 180ms var(--ease-panel), color 180ms var(--ease-panel);
  }

  .page-about .about-rail__link:hover,
  .page-about .about-rail__link:focus-visible {
    background: var(--mist);
    border-left-color: var(--saffron);
    border-bottom-color: transparent;
  }
}

@media (min-width: 1120px) {
  .page-about .about-chapter__body--split {
    display: grid;
    grid-template-columns: minmax(0, 1fr) var(--about-note-w);
    column-gap: clamp(36px, 4vw, 56px);
    align-items: start;
  }

  .page-about .about-chapter__note {
    margin-top: 4px;
  }

  .page-about .about-chapter__body--split .about-figure {
    grid-column: 1 / -1;
  }
}

@media (min-width: 1280px) {
  .page-about .about-stats {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

  .page-about .about-stats__cell {
    padding: 26px 18px 24px;
  }

  .page-about .about-stats__value {
    font-size: 30px;
  }
}

/* ---------- 动效降级 ---------- */

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail__link,
  .page-about .about-timeline__item::after {
    transition: none;
  }

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