.page-about {
  --ab-article: 44em;
  --ab-body-ink: rgba(245, 242, 233, .82);
  background: var(--ink);
  color: var(--paper);
}

.page-about .ab-crumb {
  padding-block: clamp(18px, 3vw, 32px);
  border-bottom: 1px solid var(--line);
}

.page-about .ab-crumb .breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .06em;
  color: var(--sage);
}

.page-about .ab-crumb .breadcrumb-item + .breadcrumb-item::before {
  content: "/";
  margin-right: 8px;
  color: var(--turf);
}

.page-about .ab-crumb a {
  color: var(--sage);
  text-decoration: none;
}

.page-about .ab-crumb a:hover,
.page-about .ab-crumb a:focus-visible {
  color: var(--lime);
}

/* 首屏 */
.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
  isolation: isolate;
}

.page-about .ab-hero__media {
  position: absolute;
  inset: 0;
}

.page-about .ab-hero__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  filter: saturate(.35) contrast(1.05);
  opacity: .5;
}

.page-about .ab-hero__veil {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(120% 90% at 12% 0%, rgba(23, 64, 47, .8), transparent 62%),
    linear-gradient(180deg, rgba(7, 18, 14, .84) 0%, rgba(7, 18, 14, .93) 58%, var(--ink) 100%);
}

.page-about .ab-hero__inner {
  position: relative;
  z-index: 2;
  max-width: var(--max);
  margin-inline: auto;
  padding: clamp(68px, 10vw, 132px) var(--gutter) clamp(44px, 7vw, 88px);
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: clamp(16px, 2.4vw, 26px);
  min-height: clamp(430px, 64vh, 660px);
}

.page-about .ab-hero__inner::before {
  content: "";
  position: absolute;
  inset: clamp(10px, 1.6vw, 20px);
  border: 1px solid var(--line-bright);
  pointer-events: none;
}

.page-about .ab-hero .eyebrow {
  margin: 0;
  position: relative;
  z-index: 1;
}

.page-about .ab-hero__title {
  position: relative;
  z-index: 1;
  margin: 0;
  font-family: var(--font-cond);
  font-weight: 800;
  font-size: var(--step4);
  line-height: 1;
  letter-spacing: -.01em;
  max-width: 15em;
}

.page-about .ab-hero__title em {
  font-style: normal;
  color: var(--lime);
}

.page-about .ab-hero__lede {
  position: relative;
  z-index: 1;
  margin: 0;
  max-width: 34em;
  font-size: var(--step1);
  line-height: 1.8;
  color: rgba(245, 242, 233, .86);
}

.page-about .ab-hero__facts {
  position: relative;
  z-index: 1;
  list-style: none;
  margin: clamp(6px, 1.4vw, 14px) 0 0;
  padding: clamp(14px, 2vw, 20px) 0 0;
  border-top: 1px solid var(--line-bright);
  display: flex;
  flex-wrap: wrap;
  gap: clamp(12px, 2.6vw, 40px);
  font-family: var(--font-mono);
  font-size: var(--step-1);
  letter-spacing: .02em;
  color: var(--sage);
}

.page-about .ab-hero__facts strong {
  color: var(--lime);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

/* 版心与目录 */
.page-about .ab-shell {
  max-width: var(--max);
  margin-inline: auto;
  padding: clamp(40px, 6vw, 76px) var(--gutter) clamp(56px, 8vw, 104px);
  display: grid;
  gap: clamp(30px, 4vw, 52px);
}

.page-about .ab-toc__title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--sage);
}

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

.page-about .ab-toc__link {
  display: flex;
  gap: 8px;
  align-items: baseline;
  padding: 9px 4px;
  border-bottom: 2px solid var(--line);
  color: var(--sage);
  text-decoration: none;
  font-size: var(--step-1);
  line-height: 1.4;
  white-space: nowrap;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .ab-toc__link .num {
  font-family: var(--font-mono);
  font-size: .7rem;
  color: rgba(198, 249, 74, .5);
}

.page-about .ab-toc__link:hover,
.page-about .ab-toc__link:focus-visible {
  color: var(--paper);
  border-bottom-color: var(--lime);
}

.page-about .ab-toc__link:hover .num,
.page-about .ab-toc__link:focus-visible .num {
  color: var(--lime);
}

/* 正文 */
.page-about .ab-body {
  display: grid;
  gap: clamp(40px, 6vw, 76px);
  max-width: var(--ab-article);
}

.page-about .ab-sec {
  scroll-margin-top: 128px;
}

.page-about .ab-sec__head {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 14px;
  margin-bottom: clamp(16px, 2.4vw, 24px);
}

.page-about .ab-sec__num {
  font-family: var(--font-mono);
  font-size: var(--step-1);
  letter-spacing: .08em;
  color: var(--lime);
}

.page-about .ab-sec__title {
  margin: 0;
  font-family: var(--font-cond);
  font-weight: 800;
  font-size: var(--step3);
  line-height: 1.12;
  letter-spacing: -.01em;
  color: var(--paper);
}

.page-about .ab-sec__head::after {
  content: "";
  flex: 1 1 40px;
  min-width: 24px;
  height: 1px;
  background: var(--line);
}

.page-about .ab-p {
  margin: 0 0 1.1em;
  font-size: var(--step0);
  line-height: 1.85;
  color: var(--ab-body-ink);
}

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

.page-about .ab-spike {
  margin: clamp(34px, 5vw, 52px) 0;
  padding-left: clamp(16px, 2vw, 24px);
  border-left: 2px solid var(--lime);
  font-family: var(--font-cond);
  font-weight: 800;
  font-size: clamp(1.35rem, 1rem + 1.6vw, 2rem);
  line-height: 1.35;
  letter-spacing: -.01em;
  color: var(--paper);
}

/* 三类使用者 */
.page-about .ab-who {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .ab-who__item {
  background: var(--panel);
  padding: clamp(18px, 2.6vw, 26px);
}

.page-about .ab-who__t {
  margin: 0 0 8px;
  font-family: var(--font-cond);
  font-weight: 800;
  font-size: var(--step1);
  line-height: 1.3;
  color: var(--paper);
}

.page-about .ab-who__t::before {
  content: "";
  display: inline-block;
  width: 14px;
  height: 2px;
  margin-right: 10px;
  vertical-align: middle;
  background: var(--amber);
}

.page-about .ab-who__d {
  margin: 0;
  font-size: var(--step0);
  line-height: 1.8;
  color: var(--sage);
}

/* 三条原则 */
.page-about .ab-rule {
  border-top: 1px solid var(--line);
}

.page-about .ab-rule:last-of-type {
  border-bottom: 1px solid var(--line);
}

.page-about .ab-rule__sum {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: clamp(14px, 2vw, 18px) 0;
  cursor: pointer;
  list-style: none;
}

.page-about .ab-rule__sum::-webkit-details-marker {
  display: none;
}

.page-about .ab-rule__sum::after {
  content: "+";
  flex: none;
  font-family: var(--font-mono);
  font-size: 1.05rem;
  line-height: 1;
  color: var(--lime);
}

.page-about .ab-rule[open] .ab-rule__sum::after {
  content: "–";
}

.page-about .ab-rule__sum:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 4px;
}

.page-about .ab-rule__tag {
  flex: none;
  padding: 3px 8px;
  border: 1px solid rgba(255, 166, 41, .38);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .1em;
  color: var(--amber);
  white-space: nowrap;
}

.page-about .ab-rule__title {
  flex: 1;
  font-family: var(--font-cond);
  font-weight: 800;
  font-size: var(--step2);
  line-height: 1.25;
  color: var(--paper);
}

.page-about .ab-rule__sum:hover .ab-rule__title {
  color: var(--lime);
}

.page-about .ab-rule__body {
  margin: 0 0 clamp(16px, 2vw, 22px);
  padding-left: clamp(0px, .4vw, 6px);
  max-width: 38em;
  font-size: var(--step0);
  line-height: 1.85;
  color: var(--ab-body-ink);
}

.page-about .ab-rule__body strong {
  color: var(--lime);
  font-weight: 600;
}

/* 图片 */
.page-about .ab-fig {
  margin: clamp(22px, 3vw, 32px) 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--panel);
}

.page-about .ab-fig .media-frame__img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  filter: saturate(.55) contrast(1.03);
}

.page-about .ab-fig__cap {
  padding: 12px 16px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: .76rem;
  line-height: 1.7;
  color: var(--sage);
}

/* 迭代时间轴 */
.page-about .ab-tl {
  list-style: none;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
}

.page-about .ab-tl__item {
  position: relative;
  padding: 16px 0 16px 24px;
  border-left: 1px solid var(--line);
}

.page-about .ab-tl__item::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 22px;
  width: 7px;
  height: 7px;
  background: var(--turf);
  border-radius: 50%;
  transition: background var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .ab-tl__item:hover::before {
  background: var(--lime);
  box-shadow: 0 0 0 4px rgba(198, 249, 74, .14);
}

.page-about .ab-tl__when {
  display: block;
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .08em;
  color: var(--amber);
}

.page-about .ab-tl__what {
  display: block;
  margin-top: 5px;
  font-size: var(--step0);
  line-height: 1.75;
  color: var(--ab-body-ink);
}

/* 继续了解 */
.page-about .ab-next {
  margin-top: clamp(20px, 3vw, 28px);
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .ab-next__item {
  position: relative;
  display: block;
  padding: clamp(18px, 2.6vw, 26px);
  background: var(--panel);
  text-decoration: none;
  transition: background var(--dur) var(--ease);
}

.page-about .ab-next__item::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: var(--lime);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--dur) var(--ease);
}

.page-about .ab-next__item:hover,
.page-about .ab-next__item:focus-visible {
  background: #123327;
}

.page-about .ab-next__item:hover::after,
.page-about .ab-next__item:focus-visible::after {
  transform: scaleX(1);
}

.page-about .ab-next__item:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: -4px;
}

.page-about .ab-next__k {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .14em;
  color: var(--sage);
}

.page-about .ab-next__t {
  display: block;
  font-family: var(--font-cond);
  font-weight: 800;
  font-size: var(--step1);
  line-height: 1.3;
  color: var(--paper);
}

.page-about .ab-next__d {
  display: block;
  margin-top: 7px;
  font-size: .9rem;
  line-height: 1.7;
  color: var(--sage);
}

@media (min-width: 620px) {
  .page-about .ab-next {
    grid-template-columns: 1fr 1fr;
  }

  .page-about .ab-next__item:last-child:nth-child(odd) {
    grid-column: 1 / -1;
  }
}

@media (min-width: 1000px) {
  .page-about .ab-shell {
    grid-template-columns: 236px minmax(0, 1fr);
    column-gap: clamp(40px, 6vw, 88px);
  }

  .page-about .ab-toc {
    position: sticky;
    top: 128px;
    align-self: start;
  }

  .page-about .ab-toc__list {
    display: grid;
    gap: 2px;
    overflow: visible;
  }

  .page-about .ab-toc__link {
    padding: 9px 0 9px 14px;
    border-bottom: 0;
    border-left: 2px solid var(--line);
    white-space: normal;
  }

  .page-about .ab-toc__link:hover,
  .page-about .ab-toc__link:focus-visible {
    border-left-color: var(--lime);
  }

  .page-about .ab-hero__inner {
    padding-inline: calc(var(--gutter) + 24px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-toc__link,
  .page-about .ab-rule__sum,
  .page-about .ab-tl__item::before,
  .page-about .ab-next__item,
  .page-about .ab-next__item::after {
    transition: none;
  }
}
<<<END>>>