.page-about {
  --about-text: #BFCFE8;
  --about-rail-w: 240px;
  display: block;
  background: var(--void);
  color: var(--paper);
  overflow-x: clip;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: 36px 0 44px;
  border-bottom: var(--edge);
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  top: -190px;
  right: -150px;
  width: 480px;
  height: 480px;
  background: radial-gradient(circle at center, rgba(23, 229, 200, 0.16), transparent 70%);
  pointer-events: none;
}

.page-about .breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 26px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.page-about .breadcrumbs a {
  color: var(--muted);
  text-decoration: none;
}

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

.page-about .about-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 34px;
}

.page-about .about-hero__eyebrow {
  margin: 0 0 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .about-hero h1 {
  margin: 0 0 20px;
  max-width: 20ch;
  font-size: clamp(29px, 6.2vw, 60px);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .about-hero__lede {
  margin: 0 0 28px;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--about-text);
}

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

/* ---------- 首屏数据块 ---------- */
.page-about .about-figures {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--grid);
  border: var(--edge);
}

.page-about .about-figures__item {
  background: var(--midnight);
  padding: 18px 16px;
}

.page-about .about-figures__value {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(30px, 5vw, 42px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--cyan);
}

.page-about .about-figures__value--sm {
  font-size: clamp(24px, 4vw, 32px);
}

.page-about .about-figures__label {
  display: block;
  margin-top: 10px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--muted);
}

.page-about .about-figures__item--flare .about-figures__value {
  color: var(--flare);
}

/* ---------- 分栏骨架 ---------- */
.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 34px;
  padding-top: 34px;
  padding-bottom: 72px;
}

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

/* ---------- 章节索引（移动端为横向滚动条） ---------- */
.page-about .about-rail__title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--muted);
}

.page-about .about-rail__list {
  list-style: none;
  margin: 0;
  padding: 0 0 6px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-rail__item {
  flex: 0 0 auto;
}

.page-about .toc__link {
  display: block;
  padding: 8px 14px;
  border: var(--edge);
  background: var(--midnight);
  color: var(--muted);
  font-size: 13px;
  line-height: 1.4;
  white-space: nowrap;
  text-decoration: none;
  transition: color 0.2s var(--ease), background 0.2s var(--ease), border-color 0.2s var(--ease);
}

.page-about .toc__link:hover {
  color: var(--paper);
  border-color: var(--cyan);
}

.page-about .toc__link[aria-current="true"] {
  background: var(--cyan);
  border-color: var(--cyan);
  color: var(--void);
}

/* ---------- 章节 ---------- */
.page-about .about-block {
  padding-bottom: 48px;
  margin-bottom: 48px;
  border-bottom: var(--edge);
  scroll-margin-top: calc(var(--header-h) + 28px);
}

.page-about .about-block:last-child {
  padding-bottom: 0;
  margin-bottom: 0;
  border-bottom: 0;
}

.page-about .about-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 14px;
  padding-bottom: 14px;
  margin-bottom: 22px;
  border-bottom: var(--edge);
}

.page-about .about-head__index {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .about-head__title {
  margin: 0;
  font-size: clamp(21px, 3.4vw, 32px);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-lede {
  margin: 0 0 26px;
  max-width: 64ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--about-text);
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-timeline__item {
  position: relative;
  padding: 0 0 30px 26px;
  border-left: 1px solid var(--grid);
}

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 7px;
  width: 9px;
  height: 9px;
  background: var(--cyan);
  box-shadow: 0 0 0 4px rgba(23, 229, 200, 0.13);
}

.page-about .about-timeline__item:last-child {
  padding-bottom: 0;
  border-left-color: transparent;
}

.page-about .about-timeline__year {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: 0.08em;
  color: var(--cyan);
}

.page-about .about-timeline__title {
  margin: 0 0 8px;
  font-size: 19px;
  font-weight: 800;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .about-timeline__text {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--about-text);
}

/* ---------- 图片 ---------- */
.page-about .figure {
  margin: 0 0 26px;
  border: var(--edge);
  background: var(--midnight);
  overflow: hidden;
}

.page-about .figure__frame {
  display: block;
  overflow: hidden;
  background: var(--midnight);
}

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

.page-about .figure__caption {
  display: block;
  padding: 10px 14px;
  border-top: var(--edge);
  font-size: 12px;
  line-height: 1.6;
  letter-spacing: 0.04em;
  color: var(--muted);
}

.page-about .figure--wide .figure__frame {
  aspect-ratio: 16 / 9;
}

.page-about .about-stands {
  margin-top: 4px;
  margin-bottom: 48px;
}

/* ---------- 团队分工 ---------- */
.page-about .about-roles {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--grid);
  border: var(--edge);
}

.page-about .about-roles__item {
  background: var(--midnight);
  padding: 22px 20px;
}

.page-about .about-roles__count {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 32px;
  font-weight: 700;
  line-height: 1;
  color: var(--cyan);
}

.page-about .about-roles__title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 800;
  color: var(--paper);
}

.page-about .about-roles__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--about-text);
}

/* ---------- 覆盖版图 ---------- */
.page-about .about-coverage {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 30px;
}

.page-about .about-cities {
  list-style: none;
  margin: 0 0 20px;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .about-cities__item {
  padding-left: 16px;
  border-left: 3px solid var(--cyan);
}

.page-about .about-cities__name {
  margin: 0 0 6px;
  font-size: 16px;
  font-weight: 800;
  letter-spacing: 0.02em;
  color: var(--paper);
}

.page-about .about-cities__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--about-text);
}

.page-about .about-cities__foot {
  margin: 0;
  padding-top: 16px;
  border-top: var(--edge);
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
}

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

/* ---------- 比赛日流程 ---------- */
.page-about .about-flow {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--grid);
  border: var(--edge);
}

.page-about .about-flow__step {
  background: var(--midnight);
  padding: 20px 18px;
}

.page-about .about-flow__num {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .about-flow__title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 800;
  color: var(--paper);
}

.page-about .about-flow__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--about-text);
}

/* ---------- 合作与社区 ---------- */
.page-about .about-partners {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 20px;
}

.page-about .about-partners__item {
  display: grid;
  grid-template-columns: 62px minmax(0, 1fr);
  gap: 18px;
  align-items: start;
  padding-bottom: 20px;
  border-bottom: var(--edge);
}

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

.page-about .about-partners__count {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 38px;
  font-weight: 700;
  line-height: 0.95;
  color: var(--cyan);
}

.page-about .about-partners__title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 800;
  color: var(--paper);
}

.page-about .about-partners__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--about-text);
}

/* ---------- 后续方向 ---------- */
.page-about .about-next {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--grid);
  border: var(--edge);
}

.page-about .about-next__item {
  background: var(--midnight);
  padding: 22px 20px;
}

.page-about .about-next__tag {
  display: inline-block;
  margin-bottom: 14px;
  padding: 3px 10px;
  border-radius: 6px;
  background: var(--cyan);
  color: var(--void);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
}

.page-about .about-next__title {
  margin: 0 0 10px;
  font-size: 17px;
  font-weight: 800;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .about-next__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--about-text);
}

/* ---------- 结尾引导 ---------- */
.page-about .about-cta {
  margin-top: 8px;
  padding: 30px 22px;
  border: var(--edge);
  border-left: 3px solid var(--cyan);
  background: var(--midnight);
}

.page-about .about-cta__title {
  margin: 0 0 14px;
  font-size: clamp(20px, 3vw, 26px);
  font-weight: 800;
  line-height: 1.35;
  color: var(--paper);
}

.page-about .about-cta__text {
  margin: 0 0 24px;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--about-text);
}

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

/* ---------- 中等屏幕 ---------- */
@media (min-width: 640px) {
  .page-about .about-roles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-flow {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

@media (min-width: 860px) {
  .page-about .about-coverage {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.82fr);
    gap: 38px;
    align-items: start;
  }

  .page-about .about-flow {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

/* ---------- 桌面端：粘性章节时间轴 + 左右分栏 ---------- */
@media (min-width: 980px) {
  .page-about .about-hero {
    padding: 48px 0 52px;
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7.2fr) minmax(0, 4.8fr);
    gap: 56px;
    align-items: end;
  }

  .page-about .about-shell {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: 64px;
    padding-top: 56px;
    padding-bottom: 96px;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 28px);
    align-self: start;
  }

  .page-about .about-rail__title {
    margin-bottom: 18px;
    color: var(--muted);
  }

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

  .page-about .about-rail__list::before {
    content: "";
    position: absolute;
    left: 5px;
    top: 8px;
    bottom: 8px;
    width: 1px;
    background: var(--grid);
  }

  .page-about .about-rail__item {
    position: relative;
  }

  .page-about .toc__link {
    padding: 10px 0 10px 26px;
    border: 0;
    background: transparent;
    color: var(--muted);
    font-size: 13px;
    letter-spacing: 0.04em;
    white-space: normal;
  }

  .page-about .toc__link::before {
    content: "";
    position: absolute;
    left: 0;
    top: 15px;
    width: 11px;
    height: 11px;
    background: var(--void);
    border: 1px solid var(--grid);
    transition: background 0.2s var(--ease), border-color 0.2s var(--ease), box-shadow 0.2s var(--ease);
  }

  .page-about .toc__link:hover {
    color: var(--paper);
    border-color: transparent;
  }

  .page-about .toc__link[aria-current="true"] {
    background: transparent;
    color: var(--cyan);
  }

  .page-about .toc__link[aria-current="true"]::before {
    background: var(--cyan);
    border-color: var(--cyan);
    box-shadow: 0 0 0 3px rgba(23, 229, 200, 0.16);
  }

  .page-about .about-block {
    padding-bottom: 64px;
    margin-bottom: 64px;
  }

  .page-about .about-shot {
    margin-bottom: 32px;
  }
}

/* ---------- 大屏微调 ---------- */
@media (min-width: 1240px) {
  .page-about {
    --about-rail-w: 268px;
  }

  .page-about .about-hero h1 {
    max-width: 18ch;
  }

  .page-about .about-figures__item {
    padding: 22px 20px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .toc__link,
  .page-about .toc__link::before {
    transition: none;
  }
}