.page-about {
  --about-index-w: 200px;
  --about-radius-a: 26px;
  --about-radius-b: 80px;
  padding-bottom: 5rem;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  display: grid;
  gap: 1.75rem;
  padding: 2.5rem 0 2.5rem;
  overflow: hidden;
}

.page-about .about-hero__arc {
  position: absolute;
  right: -5rem;
  bottom: -3rem;
  width: 300px;
  height: 150px;
  color: var(--cyan-700);
  opacity: 0.35;
  pointer-events: none;
}

.page-about .about-hero__aside {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.page-about .about-hero__meta {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.14em;
  color: var(--slate-400);
  margin: 0;
}

.page-about .about-hero__title {
  font-family: var(--font-display);
  font-size: clamp(1.9rem, 6.4vw, 3.2rem);
  line-height: 1.16;
  letter-spacing: -0.02em;
  font-weight: 800;
  color: var(--mist-100);
  margin: 0 0 1.25rem;
}

.page-about .about-hero__lede {
  max-width: 34em;
  margin: 0;
  font-size: 1.0625rem;
  line-height: 1.8;
  color: var(--slate-400);
}

/* ---------- 数据条 ---------- */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0 0 3.5rem;
  background: var(--line-600);
  border: 1px solid var(--line-600);
  border-radius: 3px;
  overflow: hidden;
}

.page-about .about-stats__item {
  background: var(--ink-700);
  padding: 1.25rem 1.125rem 1.375rem;
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.page-about .about-stats__num {
  font-family: var(--font-mono);
  font-size: clamp(1.75rem, 8vw, 2.4rem);
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--cyan-400);
  font-variant-numeric: tabular-nums;
}

.page-about .about-stats__sfx {
  font-size: 0.5em;
  margin-left: 0.15em;
  color: var(--cyan-700);
}

.page-about .about-stats__label {
  font-size: 0.8125rem;
  line-height: 1.5;
  color: var(--slate-400);
}

/* ---------- 索引 + 正文 ---------- */
.page-about .about-body {
  display: grid;
  gap: 2.5rem;
}

.page-about .about-index {
  border-left: 1px solid var(--line-600);
  padding-left: 1rem;
}

.page-about .about-index__title {
  margin: 0;
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  color: var(--cyan-700);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0.75rem 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.125rem;
}

.page-about .about-index__list a {
  display: inline-flex;
  align-items: baseline;
  gap: 0.45rem;
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--slate-400);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 200ms var(--ease), border-color 200ms var(--ease);
}

.page-about .about-index__list a .mono {
  font-size: 0.75rem;
  color: var(--cyan-700);
}

.page-about .about-index__list a:hover,
.page-about .about-index__list a:focus-visible {
  color: var(--cyan-400);
  border-color: var(--cyan-400);
}

.page-about .about-index__list a:hover .mono,
.page-about .about-index__list a:focus-visible .mono {
  color: var(--cyan-400);
}

.page-about .about-flow {
  display: grid;
  gap: 3.5rem;
}

/* ---------- 章节通用 ---------- */
.page-about .about-section {
  scroll-margin-top: calc(var(--coord-h) + 2rem);
}

.page-about .about-section .section-head {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  margin-bottom: 1.25rem;
}

.page-about .about-prose {
  max-width: 34em;
}

.page-about .about-prose p {
  margin: 0 0 1em;
  color: var(--mist-100);
  font-size: 1rem;
  line-height: 1.78;
}

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

.page-about .about-link {
  color: var(--cyan-400);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

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

.page-about .about-figure {
  margin: 0;
}

.page-about .about-figure .media {
  border-radius: 4px;
  overflow: hidden;
  border: 1px solid var(--line-600);
}

/* ---------- 图文错位 ---------- */
.page-about .about-split {
  display: grid;
  gap: 1.75rem;
}

/* ---------- 团队分工 ---------- */
.page-about .about-member-grid {
  display: grid;
  gap: 1.5rem;
  margin-bottom: 2.25rem;
}

.page-about .about-member {
  border-top: 2px solid var(--cyan-700);
  padding-top: 1rem;
  transition: border-color 220ms var(--ease);
}

.page-about .about-member:hover {
  border-color: var(--cyan-400);
}

.page-about .about-member__tag {
  margin: 0 0 0.5rem;
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  color: var(--cyan-400);
}

.page-about .about-member__title {
  margin: 0 0 0.6rem;
  font-size: 1.0625rem;
  line-height: 1.45;
  color: var(--mist-100);
  font-weight: 700;
}

.page-about .about-member__desc {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.72;
  color: var(--slate-400);
}

.page-about .about-figure--wide {
  margin-bottom: 2rem;
}

/* ---------- 时间轴分区 ---------- */
.page-about .about-section--zone {
  background: var(--zone-blue);
  border-radius: var(--about-radius-a) var(--about-radius-b) var(--about-radius-a) var(--about-radius-b);
  padding: 2rem 1.25rem 2.25rem;
}

.page-about .about-yearnav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.75rem;
}

.page-about .about-yearnav__link {
  display: inline-block;
  padding: 0.3rem 0.9rem;
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  color: var(--mist-100);
  text-decoration: none;
  border: 1px solid var(--cyan-700);
  border-radius: 999px;
  transition: color 180ms var(--ease), border-color 180ms var(--ease);
}

.page-about .about-yearnav__link:hover,
.page-about .about-yearnav__link:focus-visible {
  color: var(--ink-900);
  background: var(--cyan-400);
  border-color: var(--cyan-400);
}

.page-about .about-timeline {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0 0 0 1.75rem;
}

.page-about .about-timeline__item {
  position: relative;
  padding-bottom: 2rem;
  scroll-margin-top: calc(var(--coord-h) + 3rem);
}

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

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -1.75rem;
  top: 0.5rem;
  bottom: 0;
  width: 1px;
  background-image: repeating-linear-gradient(
    to bottom,
    var(--cyan-700) 0 4px,
    transparent 4px 10px
  );
}

.page-about .about-timeline__item:last-child::before {
  bottom: auto;
  height: 1rem;
}

.page-about .about-timeline__item::after {
  content: "";
  position: absolute;
  left: -1.75rem;
  top: 0.55rem;
  width: 9px;
  height: 9px;
  transform: translateX(-50%);
  border-radius: 50%;
  background: var(--cyan-400);
  box-shadow: 0 0 0 5px rgba(53, 240, 208, 0.16);
}

.page-about .about-timeline__year {
  margin: 0 0 0.35rem;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  letter-spacing: 0.08em;
  color: var(--cyan-400);
}

.page-about .about-timeline__title {
  margin: 0 0 0.45rem;
  font-size: 1.125rem;
  line-height: 1.4;
  color: var(--mist-100);
  font-weight: 700;
}

.page-about .about-timeline__text {
  margin: 0;
  max-width: 32em;
  font-size: 0.9375rem;
  line-height: 1.72;
  color: var(--mist-100);
  opacity: 0.85;
}

/* ---------- 反馈提示 ---------- */
.page-about .about-callout {
  display: grid;
  gap: 0.75rem;
  justify-items: start;
  margin-top: 1.75rem;
  padding: 1.5rem 1.25rem 1.75rem;
  background: var(--ink-700);
  border: 1px solid var(--line-600);
  border-left: 3px solid var(--ember-500);
  border-radius: 4px;
}

.page-about .about-callout__label {
  margin: 0;
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  color: var(--ember-500);
}

.page-about .about-callout__text {
  margin: 0;
  max-width: 34em;
  font-size: 1rem;
  line-height: 1.75;
  color: var(--mist-100);
}

.page-about .about-callout .btn {
  margin-top: 0.25rem;
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-member-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1.75rem;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: 4fr 8fr;
    align-items: end;
    gap: 3rem;
    padding: 4.5rem 0 3.5rem;
    min-height: 46vh;
  }

  .page-about .about-hero__arc {
    right: -2rem;
    bottom: -1.5rem;
    width: 420px;
    height: 210px;
  }

  .page-about .about-hero__aside {
    padding-bottom: 0.5rem;
  }

  .page-about .about-stats {
    margin-bottom: 5rem;
  }

  .page-about .about-body {
    grid-template-columns: var(--about-index-w) minmax(0, 1fr);
    gap: 3.5rem;
    align-items: start;
  }

  .page-about .about-index {
    position: sticky;
    top: calc(var(--coord-h) + 1.75rem);
    border-left: none;
    border-top: 1px solid var(--line-600);
    padding: 1rem 0 0;
  }

  .page-about .about-index__list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 0.7rem;
    margin-top: 0.85rem;
  }

  .page-about .about-flow {
    gap: 5rem;
  }

  .page-about .about-section .section-head {
    margin-bottom: 1.75rem;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr);
    gap: 3rem;
    align-items: center;
  }

  .page-about .about-split--rev {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.25fr);
  }

  .page-about .about-member:nth-child(2) {
    margin-top: 24px;
  }

  .page-about .about-member:nth-child(3) {
    margin-top: 48px;
  }

  .page-about .about-figure--wide {
    margin-bottom: 2.5rem;
  }

  .page-about .about-section--zone {
    padding: 3rem 3rem 3.25rem;
  }

  .page-about .about-timeline {
    padding-left: 2.25rem;
  }

  .page-about .about-timeline__item::before,
  .page-about .about-timeline__item::after {
    left: -2.25rem;
  }

  .page-about .about-timeline__item {
    padding-bottom: 2.5rem;
  }

  .page-about .about-callout {
    padding: 1.75rem 2rem 2rem;
    gap: 0.85rem;
  }
}
<<<END>>>