.page-about {
  --ab-rail: 172px;
  --ab-rail-gap: clamp(20px, 3vw, 48px);
  --ab-track: 34px;
  background: var(--sc-night);
  color: var(--sc-text);
  font-family: var(--sc-font-body);
}

/* ---------- 首屏 ---------- */

.page-about .ab-hero {
  position: relative;
  padding: clamp(88px, 13vh, 148px) 0 clamp(28px, 5vw, 52px);
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  left: var(--sc-pad);
  right: var(--sc-pad);
  bottom: 0;
  height: 1px;
  background: linear-gradient(90deg, var(--sc-cyan) 0%, var(--sc-line) 22%, transparent 72%);
  opacity: .55;
}

.page-about .ab-hero__eyebrow {
  margin: 20px 0 0;
}

.page-about .ab-hero__title {
  margin: 14px 0 20px;
  max-width: 20em;
  font-family: var(--sc-font-display);
  font-weight: 800;
  letter-spacing: -.02em;
  line-height: 1.16;
  font-size: clamp(28px, 5.4vw, 60px);
}

.page-about .ab-hero__lede {
  max-width: 62ch;
  margin: 0;
  font-size: clamp(15px, 1.15vw, 17.5px);
  line-height: 1.78;
  color: var(--sc-text);
}

.page-about .ab-hero__figure {
  margin: clamp(32px, 5vw, 58px) 0 0;
}

/* ---------- 框架 ---------- */

.page-about .ab-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 40px);
  padding-top: clamp(26px, 4vw, 46px);
  padding-bottom: clamp(64px, 10vw, 124px);
}

/* ---------- 章节索引 ---------- */

.page-about .ab-index {
  display: flex;
  gap: 2px;
  margin: 0;
  padding: 0 0 6px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .ab-index::-webkit-scrollbar {
  display: none;
}

.page-about .ab-index__item {
  flex: 0 0 auto;
}

.page-about .ab-index__link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 9px 12px;
  white-space: nowrap;
  text-decoration: none;
  color: var(--sc-muted);
  font-size: 14px;
  line-height: 1.3;
  border-bottom: 2px solid transparent;
  transition: color var(--sc-t) var(--sc-ease), border-color var(--sc-t) var(--sc-ease);
}

.page-about .ab-index__num {
  font-family: var(--sc-font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  opacity: .75;
}

.page-about .ab-index__link:hover,
.page-about .ab-index__link:focus-visible,
.page-about .ab-index__link.is-current {
  color: var(--sc-cyan);
  border-bottom-color: var(--sc-cyan);
}

.page-about .ab-index__link:focus-visible {
  outline: 2px solid var(--sc-cyan);
  outline-offset: 2px;
}

/* ---------- 正文列 ---------- */

.page-about .ab-body {
  position: relative;
  min-width: 0;
}

.page-about .ab-section {
  position: relative;
  padding: clamp(38px, 6vw, 74px) 0;
  border-bottom: 1px solid var(--sc-line);
}

.page-about .ab-section:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .ab-section__head {
  position: relative;
}

.page-about .ab-section__head .sc-eyebrow {
  margin: 0;
}

.page-about .ab-node {
  display: block;
  width: 8px;
  height: 8px;
  margin-bottom: 14px;
  background: var(--sc-cyan);
}

.page-about .ab-h2 {
  margin: 10px 0 0;
  font-family: var(--sc-font-display);
  font-weight: 800;
  letter-spacing: -.02em;
  line-height: 1.22;
  font-size: clamp(23px, 3.3vw, 38px);
}

.page-about .ab-prose {
  margin-top: clamp(18px, 2.4vw, 28px);
}

.page-about .ab-prose p {
  max-width: 68ch;
  margin: 0 0 1.15em;
  font-size: clamp(15px, 1.05vw, 17px);
  line-height: 1.78;
  color: var(--sc-text);
}

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

/* ---------- 图文对 ---------- */

.page-about .ab-pair {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 3.4vw, 40px);
  align-items: start;
  margin-top: clamp(20px, 2.6vw, 30px);
}

.page-about .ab-figure {
  margin: 0;
  background: var(--sc-stand);
  border: 1px solid var(--sc-line);
}

.page-about .ab-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  filter: saturate(.78) contrast(1.04);
}

.page-about .ab-hero__figure img {
  aspect-ratio: 12 / 7;
}

.page-about .ab-figure figcaption {
  padding: 10px 14px;
  border-top: 1px solid var(--sc-line);
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--sc-muted);
}

/* ---------- 值班时段 ---------- */

.page-about .ab-shifts {
  list-style: none;
  margin: clamp(26px, 3.6vw, 40px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--sc-line);
  border: 1px solid var(--sc-line);
}

.page-about .ab-shift {
  padding: 22px 20px 26px;
  background: var(--sc-stand);
  border-top: 2px solid transparent;
  transition: border-color var(--sc-t) var(--sc-ease), background var(--sc-t) var(--sc-ease);
}

.page-about .ab-shift:nth-child(2) {
  background: var(--sc-blue);
}

.page-about .ab-shift:nth-child(3) {
  background: var(--sc-blue-soft);
}

.page-about .ab-shift:hover {
  border-top-color: var(--sc-cyan);
}

.page-about .ab-shift__label {
  display: block;
  font-family: var(--sc-font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--sc-cyan);
}

.page-about .ab-shift__title {
  margin: 10px 0 10px;
  font-family: var(--sc-font-display);
  font-weight: 700;
  font-size: 19px;
  letter-spacing: -.01em;
  line-height: 1.35;
}

.page-about .ab-shift__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--sc-muted);
}

/* ---------- 时间轴 ---------- */

.page-about .ab-timeline {
  list-style: none;
  position: relative;
  margin: clamp(26px, 3.6vw, 42px) 0 0;
  padding: 0;
}

.page-about .ab-timeline::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 12px;
  bottom: 30px;
  width: 1px;
  background: linear-gradient(180deg, var(--sc-cyan) 0%, var(--sc-line) 18%, var(--sc-line) 82%, transparent 100%);
}

.page-about .ab-tl-item {
  position: relative;
  padding: 0 0 clamp(28px, 4vw, 46px) calc(var(--ab-track) + 6px);
}

.page-about .ab-tl-item:last-child {
  padding-bottom: 0;
}

.page-about .ab-tl-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  width: 8px;
  height: 8px;
  background: var(--sc-cyan);
}

.page-about .ab-tl-year {
  display: block;
  font-family: var(--sc-font-display);
  font-weight: 800;
  font-size: clamp(24px, 3vw, 34px);
  line-height: 1;
  letter-spacing: -.03em;
  font-variant-numeric: tabular-nums;
  color: var(--sc-chalk);
}

.page-about .ab-tl-body {
  margin-top: 10px;
}

.page-about .ab-tl-title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--sc-text);
}

.page-about .ab-tl-body p {
  max-width: 62ch;
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--sc-muted);
}

/* ---------- 数据锚点 ---------- */

.page-about .ab-stats {
  list-style: none;
  margin: clamp(22px, 3vw, 32px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--sc-line);
  border: 1px solid var(--sc-line);
}

.page-about .ab-stat {
  padding: 20px 20px 22px;
  background: var(--sc-blue);
}

.page-about .ab-stat:nth-child(2) {
  background: var(--sc-stand);
}

.page-about .ab-stat__num {
  display: block;
  font-family: var(--sc-font-display);
  font-weight: 800;
  font-size: clamp(36px, 4.6vw, 54px);
  line-height: 1;
  letter-spacing: -.04em;
  font-variant-numeric: tabular-nums;
  color: var(--sc-chalk);
}

.page-about .ab-stat__unit {
  display: block;
  margin-top: 8px;
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--sc-cyan);
}

.page-about .ab-stat__desc {
  margin: 12px 0 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--sc-muted);
}

/* ---------- 更新节奏 ---------- */

.page-about .ab-promises {
  list-style: none;
  margin: clamp(24px, 3.2vw, 36px) 0 0;
  padding: 0;
  border-top: 1px solid var(--sc-line);
}

.page-about .ab-promise {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 18px 0;
  border-bottom: 1px solid var(--sc-line);
}

.page-about .ab-promise__key {
  font-family: var(--sc-font-display);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: -.01em;
  color: var(--sc-cyan);
}

.page-about .ab-promise__val {
  font-size: 15px;
  line-height: 1.75;
  color: var(--sc-text);
}

/* ---------- 收尾入口 ---------- */

.page-about .ab-cta {
  margin-top: clamp(32px, 4.5vw, 52px);
  padding-top: clamp(22px, 3vw, 32px);
  border-top: 1px solid var(--sc-line);
}

.page-about .ab-cta__text {
  margin: 0 0 16px;
  font-size: clamp(16px, 1.3vw, 19px);
  line-height: 1.6;
  color: var(--sc-text);
}

.page-about .ab-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-about .ab-stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

  .page-about .ab-promise {
    grid-template-columns: 150px minmax(0, 1fr);
    gap: 24px;
    align-items: baseline;
  }
}

@media (min-width: 720px) {
  .page-about .ab-body {
    padding-left: var(--ab-track);
  }

  .page-about .ab-body::before {
    content: "";
    position: absolute;
    left: 0;
    top: 10px;
    bottom: 40px;
    width: 1px;
    background: linear-gradient(180deg, var(--sc-cyan) 0%, var(--sc-line) 140px, var(--sc-line) 72%, transparent 100%);
  }

  .page-about .ab-node {
    position: absolute;
    left: calc(var(--ab-track) * -1);
    top: 3px;
    margin-bottom: 0;
  }
}

@media (min-width: 860px) {
  .page-about .ab-pair {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.08fr);
    gap: clamp(28px, 3.6vw, 48px);
  }

  .page-about .ab-pair--media-last .ab-pair__media {
    order: 2;
  }

  .page-about .ab-pair--media-first {
    grid-template-columns: minmax(0, .92fr) minmax(0, 1.12fr);
  }
}

@media (min-width: 960px) {
  .page-about .ab-shell {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: var(--ab-rail-gap);
    align-items: start;
  }

  .page-about .ab-rail {
    position: sticky;
    top: 108px;
    align-self: start;
  }

  .page-about .ab-index {
    display: block;
    overflow: visible;
    padding: 0;
    border-left: 1px solid var(--sc-line);
  }

  .page-about .ab-index__item {
    display: block;
  }

  .page-about .ab-index__link {
    margin-left: -1px;
    padding: 10px 12px 10px 14px;
    border-bottom: 0;
    border-left: 2px solid transparent;
    white-space: normal;
  }

  .page-about .ab-index__link:hover,
  .page-about .ab-index__link:focus-visible,
  .page-about .ab-index__link.is-current {
    border-bottom-color: transparent;
    border-left-color: var(--sc-cyan);
  }
}

@media (min-width: 1200px) {
  .page-about .ab-rail {
    --ab-rail: 188px;
  }

  .page-about .ab-tl-item {
    display: grid;
    grid-template-columns: 132px minmax(0, 1fr);
    gap: 28px;
    align-items: start;
  }

  .page-about .ab-tl-body {
    margin-top: -2px;
  }

  .page-about .ab-tl-item::before {
    top: 12px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-index__link,
  .page-about .ab-shift {
    transition: none;
  }
}
<<<END>>>