.page-about {
  --about-gap: clamp(56px, 8vw, 116px);
  --about-index-w: 236px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(28px, 5vw, 60px) 0 clamp(40px, 6vw, 76px);
  background:
    radial-gradient(circle at 50% -10%, rgba(15, 169, 124, .22), transparent 62%),
    radial-gradient(circle at 88% 100%, rgba(255, 91, 46, .1), transparent 46%),
    var(--space);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: repeating-linear-gradient(180deg, var(--line-soft) 0 1px, transparent 1px var(--grid-step));
  opacity: .55;
  pointer-events: none;
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, .9), transparent 72%);
}

.page-about .about-hero__inner {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.page-about .about-hero__crumb {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
  font-size: 13px;
  color: var(--ink-dim);
  letter-spacing: .04em;
}

.page-about .about-hero__crumb a {
  color: var(--tick);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .18s ease, border-color .18s ease;
}

.page-about .about-hero__crumb a:hover {
  color: var(--mint);
  border-bottom-color: var(--mint);
}

.page-about .about-hero__crumb [aria-current="page"] {
  color: var(--ink);
}

.page-about .about-hero__eyebrow {
  margin: clamp(20px, 3vw, 34px) 0 0;
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  max-width: 15em;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(32px, 6.6vw, 68px);
  line-height: 1.12;
  letter-spacing: -.012em;
  color: var(--ink);
}

.page-about .about-hero__lede {
  margin: clamp(18px, 2.6vw, 28px) auto 0;
  max-width: 40em;
  color: var(--ink-dim);
  font-size: clamp(15px, 1.7vw, 17px);
  line-height: 1.85;
}

/* 首屏赛程节奏条 */
.page-about .hero-timeline {
  width: 100%;
  max-width: 880px;
  margin-top: clamp(32px, 5vw, 58px);
}

.page-about .hero-timeline__key {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .22em;
  color: var(--tick);
}

.page-about .hero-timeline__rail {
  position: relative;
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px 10px;
}

.page-about .hero-timeline__rail::before {
  content: none;
}

.page-about .hero-timeline__node {
  position: relative;
  padding-top: 18px;
  font-size: 13.5px;
  line-height: 1.5;
  color: var(--ink-dim);
}

.page-about .hero-timeline__node::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, var(--grass), var(--line-soft));
}

.page-about .hero-timeline__node::after {
  content: "";
  position: absolute;
  top: -3px;
  left: 0;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--grass);
  box-shadow: 0 0 0 4px rgba(15, 169, 124, .16);
}

@media (min-width: 780px) {
  .page-about .hero-timeline__rail {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0 22px;
  }

  .page-about .hero-timeline__node::before {
    background: var(--line-strong);
  }
}

/* ---------- 章节主体 ---------- */
.page-about .about-chapters {
  position: relative;
  padding: var(--about-gap) 0;
}

.page-about .about-chapters__sr {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.page-about .about-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(26px, 4vw, 52px);
}

.page-about .about-index__title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .22em;
  color: var(--tick);
}

.page-about .about-index__list {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 4px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-index__list .toc__link {
  display: block;
  white-space: nowrap;
  padding: 8px 15px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  color: var(--ink-dim);
  font-size: 13.5px;
  text-decoration: none;
  transition: color .18s ease, border-color .18s ease, background-color .18s ease;
}

.page-about .about-index__list .toc__link:hover,
.page-about .about-index__list .toc__link.is-active,
.page-about .about-index__list .toc__link[aria-current="true"] {
  color: var(--ink);
  border-color: var(--grass);
  background: rgba(15, 169, 124, .12);
}

@media (min-width: 1024px) {
  .page-about .about-chapters::before {
    content: "";
    position: absolute;
    top: 0;
    bottom: 0;
    left: calc((100% - var(--wrap)) / 2 - 26px);
    width: 26px;
    background-image: repeating-linear-gradient(180deg, var(--line) 0 1px, transparent 1px var(--grid-step));
    pointer-events: none;
  }

  .page-about .about-layout {
    grid-template-columns: var(--about-index-w) minmax(0, 1fr);
    gap: clamp(44px, 6vw, 92px);
  }

  .page-about .about-index {
    position: sticky;
    top: 168px;
    align-self: start;
  }

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

  .page-about .about-index__list .toc__link {
    border: 0;
    border-left: 2px solid transparent;
    border-radius: 0 10px 10px 0;
    padding: 10px 14px;
    white-space: normal;
    font-size: 14px;
    line-height: 1.5;
  }
}

.page-about .about-body {
  display: grid;
  gap: clamp(44px, 6vw, 88px);
  min-width: 0;
}

.page-about .about-chapter {
  min-width: 0;
}

.page-about .about-chapter__num {
  display: block;
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .24em;
  color: var(--grass);
}

.page-about .about-chapter__title {
  margin: 0 0 18px;
  font-family: var(--font-sans);
  font-weight: 800;
  font-size: clamp(24px, 3.6vw, 38px);
  line-height: 1.22;
  letter-spacing: -.01em;
  color: var(--ink);
}

.page-about .about-chapter .prose p {
  margin: 0 0 15px;
  max-width: 40em;
  color: var(--ink-dim);
  font-size: 15.5px;
  line-height: 1.9;
}

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

/* 数据条 */
.page-about .about-facts {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin: clamp(22px, 3vw, 34px) 0 0;
  padding: 0;
  list-style: none;
  background: var(--line-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.page-about .about-facts__item {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 16px 18px;
  background: var(--slate);
}

.page-about .about-facts__num {
  flex: none;
  font-family: var(--font-mono);
  font-size: 26px;
  line-height: 1;
  color: var(--flare);
}

.page-about .about-facts__label {
  font-size: 14px;
  line-height: 1.6;
  color: var(--ink-dim);
}

@media (min-width: 780px) {
  .page-about .about-facts {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-facts__item {
    flex-direction: column;
    gap: 10px;
    padding: 22px 20px;
  }
}

/* 图文并排 */
.page-about .about-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(18px, 3vw, 32px);
  align-items: start;
}

@media (min-width: 780px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, .92fr) minmax(0, 1.08fr);
    gap: clamp(24px, 4vw, 44px);
  }

  .page-about .about-split--flip {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, .92fr);
  }
}

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

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

.page-about .about-figure .media img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

.page-about .about-figure .media__cap {
  display: block;
  margin-top: 10px;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--tick);
}

/* 草原通栏 */
.page-about .about-grass-banner {
  position: relative;
  margin: 6px 0 clamp(20px, 3vw, 30px);
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 1px solid var(--line);
}

.page-about .about-grass-banner .media {
  border: 0;
  border-radius: 0;
  background: var(--space);
}

.page-about .about-grass-banner .media img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

.page-about .about-grass-banner__veil {
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(11, 26, 46, .12) 0%, rgba(11, 26, 46, .62) 100%);
  pointer-events: none;
}

/* ---------- 发展脉络 ---------- */
.page-about .about-timeline {
  padding: var(--about-gap) 0;
  background: linear-gradient(180deg, var(--slate) 0%, var(--space) 100%);
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-timeline__head {
  margin-bottom: clamp(30px, 4vw, 52px);
}

.page-about .about-timeline__head .section-title {
  margin: 12px 0 0;
  color: var(--ink);
}

.page-about .about-timeline__rail {
  display: grid;
  grid-template-columns: 1fr;
  gap: 26px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .tl-node {
  position: relative;
  padding-left: 28px;
}

.page-about .tl-node::before {
  content: "";
  position: absolute;
  left: 0;
  top: 5px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--grass);
  box-shadow: 0 0 0 4px rgba(15, 169, 124, .16);
}

.page-about .tl-node::after {
  content: "";
  position: absolute;
  left: 4px;
  top: 20px;
  bottom: -26px;
  width: 1px;
  background: var(--line);
}

.page-about .tl-node:last-child::after {
  content: none;
}

.page-about .tl-node__year {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: .1em;
  color: var(--mint);
}

.page-about .tl-node__title {
  margin: 0 0 8px;
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.4;
  color: var(--ink);
}

.page-about .tl-node__desc {
  margin: 0;
  max-width: 34em;
  font-size: 14px;
  line-height: 1.8;
  color: var(--ink-dim);
}

.page-about .tl-node--now::before {
  background: var(--flare);
  box-shadow: 0 0 0 4px rgba(255, 91, 46, .2);
}

.page-about .tl-node--now .tl-node__year {
  color: var(--ember);
}

@media (min-width: 900px) {
  .page-about .about-timeline__rail {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0;
  }

  .page-about .tl-node {
    padding: 26px 26px 0 0;
    border-top: 1px solid var(--line);
    transition: border-color .22s ease;
  }

  .page-about .tl-node:hover {
    border-top-color: var(--grass);
  }

  .page-about .tl-node::before {
    top: -5px;
    left: 0;
  }

  .page-about .tl-node::after {
    content: none;
  }

  .page-about .tl-node__desc {
    max-width: none;
  }
}

/* ---------- 结尾 ---------- */
.page-about .about-next {
  position: relative;
  padding: var(--about-gap) 0;
  background:
    radial-gradient(circle at 50% 120%, rgba(255, 91, 46, .16), transparent 58%),
    var(--space);
  overflow: hidden;
}

.page-about .about-next__inner {
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.page-about .about-next__title {
  margin: 14px 0 0;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(26px, 4.4vw, 46px);
  line-height: 1.2;
  letter-spacing: -.01em;
  color: var(--ink);
}

.page-about .about-next__lede {
  margin: 18px auto 0;
  max-width: 38em;
  color: var(--ink-dim);
  font-size: clamp(15px, 1.6vw, 16.5px);
  line-height: 1.85;
}

.page-about .about-next__actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-top: clamp(24px, 3vw, 36px);
}

.page-about .about-next__note {
  margin: clamp(24px, 3vw, 36px) 0 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--tick);
}
<<<END>>>