.page-about {
  background: var(--ink-950);
  color: var(--mist-100);
  --about-rail-w: 208px;
  --about-rule: 2px solid var(--ink-700);
}

.page-about .shell {
  width: 100%;
  max-width: 1400px;
  margin-inline: auto;
  padding-inline: var(--gutter);
}

/* ---------- 页头 ---------- */

.page-about .about-head {
  padding-top: clamp(32px, 6vw, 76px);
  padding-bottom: clamp(28px, 5vw, 56px);
}

.page-about .about-head__grid {
  display: grid;
  gap: 26px;
  margin-top: clamp(22px, 4vw, 40px);
}

@media (min-width: 900px) {
  .page-about .about-head__grid {
    grid-template-columns: minmax(0, 1fr) 210px;
    gap: 56px;
    align-items: end;
  }
}

.page-about .about-head__title {
  margin: 14px 0 20px;
  max-width: 20ch;
  color: var(--paper-050);
}

.page-about .about-head__lede {
  max-width: 60ch;
  color: var(--mist-100);
}

.page-about .about-head__aside {
  border-left: 3px solid var(--clay-600);
  padding-left: 18px;
}

.page-about .about-head__aside-label {
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  color: var(--slate-400);
  text-transform: uppercase;
}

.page-about .about-head__big {
  margin: 6px 0 4px;
  font-size: clamp(3rem, 9vw, 4.5rem);
  line-height: 1;
  font-weight: 700;
  color: var(--neon-400);
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
}

.page-about .about-head__aside-note {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.6;
  color: var(--slate-400);
}

/* ---------- 关键数字带 ---------- */

.page-about .about-facts__list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 20px;
  margin: clamp(30px, 5vw, 52px) 0 0;
  padding: 0;
  list-style: none;
}

@media (min-width: 760px) {
  .page-about .about-facts__list {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 18px 26px;
  }
}

.page-about .about-facts__list > li {
  border-left: 2px solid var(--ink-700);
  padding-left: 14px;
}

.page-about .about-facts__label {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.12em;
  color: var(--slate-400);
}

.page-about .about-facts__num {
  display: block;
  margin-top: 8px;
  font-family: var(--font-mono);
  font-size: var(--fs-28);
  font-weight: 700;
  line-height: 1;
  color: var(--paper-050);
  font-variant-numeric: tabular-nums;
}

/* ---------- 主栅格 ---------- */

.page-about .about-body {
  display: grid;
  gap: 34px;
  padding-bottom: clamp(56px, 9vw, 112px);
}

@media (min-width: 1024px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: 58px;
  }
}

/* ---------- 左侧索引栏 ---------- */

.page-about .about-rail {
  align-self: start;
  padding-bottom: 6px;
  border-bottom: var(--about-rule);
}

.page-about .about-rail__label {
  font-size: var(--fs-12);
  letter-spacing: 0.16em;
  color: var(--clay-600);
  margin: 0 0 12px;
}

.page-about .about-rail__list {
  display: flex;
  gap: 16px;
  margin: 0;
  padding: 0 0 4px;
  list-style: none;
  overflow-x: auto;
}

.page-about .about-rail__list li {
  flex: 0 0 auto;
}

.page-about .about-rail__list a {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  font-size: var(--fs-14);
  color: var(--slate-400);
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--speed);
}

.page-about .about-rail__no {
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  color: var(--ink-700);
  -webkit-text-stroke: 0;
}

@media (min-width: 1024px) {
  .page-about .about-rail {
    position: sticky;
    top: 108px;
    border-bottom: 0;
    border-right: var(--about-rule);
    padding-right: 24px;
    max-height: calc(100vh - 160px);
  }

  .page-about .about-rail__list {
    display: block;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-rail__list li + li {
    margin-top: 2px;
  }

  .page-about .about-rail__list a {
    display: flex;
    gap: 10px;
    padding: 9px 0 9px 12px;
    border-left: 2px solid var(--ink-800);
    white-space: normal;
    line-height: 1.4;
  }

  .page-about .about-rail__list a:hover,
  .page-about .about-rail__list a:focus-visible {
    color: var(--mist-100);
    border-left-color: var(--neon-400);
  }

  .page-about .about-rail__list a:hover .about-rail__no,
  .page-about .about-rail__list a:focus-visible .about-rail__no {
    color: var(--clay-600);
  }
}

/* ---------- 章节 ---------- */

.page-about .about-sec {
  padding-block: clamp(40px, 6.5vw, 76px);
  border-top: var(--about-rule);
}

.page-about .about-content > .about-sec:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-sec__head {
  display: flex;
  align-items: baseline;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: clamp(20px, 3vw, 32px);
}

.page-about .about-sec__num {
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  color: var(--clay-600);
  border: 2px solid var(--clay-600);
  padding: 3px 9px;
  line-height: 1.2;
}

.page-about .about-sec .t-h2 {
  margin: 0;
  color: var(--paper-050);
  max-width: 26ch;
}

.page-about .about-lead {
  max-width: 62ch;
  color: var(--mist-100);
}

/* ---------- 双栏 ---------- */

.page-about .about-split,
.page-about .about-team {
  display: grid;
  gap: 28px;
}

@media (min-width: 900px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: 48px;
  }

  .page-about .about-team {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    gap: 44px;
    align-items: start;
  }
}

.page-about .rail {
  border-left: 2px solid var(--clay-600);
  padding-left: 18px;
}

.page-about .rail__note {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--slate-400);
}

/* ---------- 图片 ---------- */

.page-about .about-media__img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: var(--about-rule);
}

.page-about .about-media .media__cap,
.page-about .about-plate .media__cap {
  margin-top: 10px;
  font-size: var(--fs-12);
  line-height: 1.6;
  color: var(--slate-400);
}

/* ---------- 折叠组 ---------- */

.page-about .about-foldset {
  margin-top: 34px;
}

.page-about .about-foldset__btn {
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  padding: 8px 16px;
}

.page-about .about-fold {
  margin-top: 12px;
}

.page-about .about-fold .fold__summary {
  font-size: var(--fs-17);
  font-weight: 600;
  color: var(--paper-050);
  padding: 14px 16px;
  border: var(--about-rule);
  background: var(--ink-900);
  cursor: pointer;
  transition: border-color var(--speed), color var(--speed);
}

.page-about .about-fold .fold__summary:hover,
.page-about .about-fold .fold__summary:focus-visible {
  border-color: var(--neon-400);
  color: var(--neon-400);
}

.page-about .about-fold[open] .fold__summary {
  border-bottom-color: var(--ink-800);
}

.page-about .about-fold .fold__body {
  border: var(--about-rule);
  border-top: 0;
  background: var(--ink-800);
  padding: 16px 18px;
}

.page-about .about-fold .fold__body p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--mist-100);
  max-width: 66ch;
}

/* ---------- 内容分类 ---------- */

.page-about .about-types {
  list-style: none;
  margin: clamp(26px, 4vw, 40px) 0 0;
  padding: 0;
  border-top: var(--about-rule);
}

.page-about .about-type {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 14px;
  padding: 20px 0;
  border-bottom: var(--about-rule);
  transition: background var(--speed);
}

@media (min-width: 700px) {
  .page-about .about-type {
    grid-template-columns: 56px minmax(0, 1fr);
    gap: 22px;
    padding: 24px 12px;
  }

  .page-about .about-type:hover {
    background: var(--ink-900);
  }
}

.page-about .about-type__code {
  font-size: var(--fs-12);
  letter-spacing: 0.16em;
  color: var(--slate-400);
  padding-top: 7px;
}

.page-about .about-type__body .t-h3 {
  margin: 0 0 8px;
  color: var(--paper-050);
  letter-spacing: -0.01em;
}

.page-about .about-type__body p {
  margin: 0;
  font-size: var(--fs-17);
  line-height: 1.75;
  color: var(--mist-100);
  max-width: 62ch;
}

/* ---------- 时间轴 ---------- */

.page-about .about-plate {
  margin: clamp(24px, 4vw, 40px) 0 clamp(30px, 5vw, 48px);
}

.page-about .about-plate--tall {
  margin: 0;
}

.page-about .about-timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 18px;
  position: relative;
}

@media (min-width: 900px) {
  .page-about .about-timeline {
    gap: 22px;
    padding-left: 62px;
  }

  .page-about .about-timeline::before {
    content: "";
    position: absolute;
    left: 20px;
    top: 10px;
    bottom: 10px;
    width: 2px;
    background: var(--ink-700);
  }

  .page-about .about-timeline__item:nth-child(even) {
    transform: translateX(18px);
  }
}

.page-about .about-timeline__item {
  position: relative;
  border: var(--about-rule);
  background: var(--ink-900);
  padding: 20px 22px;
  transition: border-color var(--speed), background var(--speed);
}

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -2px;
  top: -2px;
  bottom: -2px;
  width: 4px;
  background: var(--ink-700);
  transition: background var(--speed);
}

.page-about .about-timeline__item:hover {
  border-color: var(--ink-700);
  background: var(--ink-800);
}

.page-about .about-timeline__item:hover::before {
  background: var(--neon-400);
}

.page-about .about-timeline__ver {
  display: inline-block;
  font-size: var(--fs-12);
  letter-spacing: 0.18em;
  color: var(--neon-400);
  border-bottom: 2px solid var(--clay-600);
  padding-bottom: 3px;
  margin-bottom: 12px;
  font-variant-numeric: tabular-nums;
}

.page-about .about-timeline__item .t-h3 {
  margin: 0 0 10px;
  color: var(--paper-050);
}

.page-about .about-timeline__item p {
  margin: 0;
  font-size: var(--fs-17);
  line-height: 1.75;
  color: var(--mist-100);
  max-width: 64ch;
}

.page-about .about-timeline__hint {
  margin-top: 12px;
  font-size: var(--fs-14);
  color: var(--slate-400);
  transition: color var(--speed);
}

.page-about .about-timeline__item:hover .about-timeline__hint {
  color: var(--neon-400);
}

/* ---------- 更新节奏 ---------- */

.page-about .about-rhythm {
  display: grid;
  gap: 26px;
}

@media (min-width: 760px) {
  .page-about .about-rhythm {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 34px;
    align-items: start;
  }

  .page-about .about-rhythm__card:nth-child(2) {
    margin-top: 26px;
  }

  .page-about .about-rhythm__card:nth-child(3) {
    margin-top: 52px;
  }
}

.page-about .about-rhythm__card {
  border-top: 3px solid var(--clay-600);
  padding-top: 18px;
}

.page-about .about-rhythm__time {
  margin: 0 0 14px;
  font-size: var(--fs-22);
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--neon-400);
  font-variant-numeric: tabular-nums;
}

.page-about .about-rhythm__card .t-h3 {
  margin: 0 0 10px;
  color: var(--paper-050);
}

.page-about .about-rhythm__card p {
  margin: 0;
  font-size: var(--fs-17);
  line-height: 1.75;
  color: var(--mist-100);
}

.page-about .about-rhythm__foot {
  margin: clamp(30px, 5vw, 48px) 0 0;
  padding-left: 18px;
  border-left: 2px solid var(--ink-700);
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--slate-400);
  max-width: 66ch;
}

/* ---------- 继续了解 ---------- */

.page-about .about-sec--next {
  border-top: var(--about-rule);
}

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

@media (min-width: 900px) {
  .page-about .about-next {
    grid-template-columns: minmax(0, 1.45fr) minmax(0, 0.85fr);
    gap: 52px;
    align-items: start;
  }
}

.page-about .about-next__links {
  display: grid;
}

.page-about .about-link {
  display: grid;
  gap: 6px;
  padding: 18px 0;
  border-bottom: var(--about-rule);
  text-decoration: none;
  color: var(--mist-100);
  transition: padding-left var(--speed), color var(--speed);
}

.page-about .about-link:first-child {
  border-top: var(--about-rule);
}

.page-about .about-link__name {
  font-size: var(--fs-22);
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--paper-050);
}

.page-about .about-link__desc {
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--slate-400);
}

.page-about .about-link:hover,
.page-about .about-link:focus-visible {
  padding-left: 12px;
}

.page-about .about-link:hover .about-link__name,
.page-about .about-link:focus-visible .about-link__name {
  color: var(--neon-400);
}

.page-about .about-link:hover .about-link__desc,
.page-about .about-link:focus-visible .about-link__desc {
  color: var(--mist-100);
}

.page-about .about-plate--tall .about-media__img {
  border-color: var(--clay-600);
}

/* ---------- 动效退让 ---------- */

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail__list a,
  .page-about .about-type,
  .page-about .about-timeline__item,
  .page-about .about-timeline__item::before,
  .page-about .about-timeline__hint,
  .page-about .about-link,
  .page-about .about-fold .fold__summary {
    transition: none !important;
  }

  .page-about .about-timeline__item:nth-child(even) {
    transform: none;
  }
}
<<<END>>>