.page-about {
  --about-gap: clamp(1.25rem, 3.5vw, 2.5rem);
  --about-gap-lg: clamp(2rem, 6vw, 4.5rem);
  --about-hair: 1px solid var(--line);
  --about-hair-dark: 1px solid var(--line-dark);
  --about-body-light: rgba(20, 24, 31, .74);
  --about-body-dark: rgba(244, 239, 230, .7);
}

.page-about [id] {
  scroll-margin-top: calc(var(--header-h) + 72px);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding-top: calc(var(--header-h) + clamp(2.5rem, 8vw, 5rem));
  padding-bottom: clamp(2.25rem, 6vw, 4rem);
  overflow: hidden;
}

.page-about .about-hero__crumbs {
  margin-bottom: clamp(1.5rem, 4vw, 2.5rem);
}

.page-about .about-hero__grid {
  row-gap: var(--about-gap);
  align-items: start;
}

.page-about .about-hero__title {
  margin: .85rem 0 0;
  font-weight: 200;
  letter-spacing: -.03em;
  line-height: 1.02;
  color: var(--warm);
}

.page-about .about-hero__dek {
  margin: 0;
  max-width: 44ch;
  font-size: 1.0625rem;
  line-height: 1.9;
  color: var(--about-body-dark);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: var(--about-gap) 0 0;
  padding: 0;
  background: var(--line-dark);
  border: var(--about-hair-dark);
}

.page-about .about-hero__fact {
  background: var(--navy);
  padding: .9rem 1rem 1rem;
}

.page-about .about-hero__fact dt {
  margin: 0;
  font-family: var(--font-mono);
  font-size: .75rem;
  letter-spacing: .08em;
  color: rgba(244, 239, 230, .55);
}

.page-about .about-hero__fact dd {
  margin: .45rem 0 0;
  font-size: 1.875rem;
  font-weight: 600;
  line-height: 1;
  color: var(--cyan);
}

.page-about .about-hero__fact dd em {
  font-style: normal;
  font-size: .65em;
  color: var(--cyan-deep);
  margin-left: .1em;
}

/* ---------- 页内目录 ---------- */

.page-about .about-toc {
  position: sticky;
  top: var(--header-h);
  z-index: 6;
  background: var(--warm);
  border-bottom: var(--about-hair);
}

.page-about .about-toc__list {
  display: flex;
  align-items: center;
  gap: clamp(1rem, 3vw, 1.75rem);
  list-style: none;
  margin: 0;
  padding: .7rem 0;
  overflow-x: auto;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-toc__list::-webkit-scrollbar {
  display: none;
}

.page-about .about-toc__link {
  display: inline-flex;
  align-items: baseline;
  gap: .45rem;
  white-space: nowrap;
  padding-bottom: .3rem;
  border-bottom: 2px solid transparent;
  font-size: .875rem;
  color: var(--rock);
  text-decoration: none;
  transition: color var(--ease), border-color var(--ease);
}

.page-about .about-toc__link .num {
  font-size: .75rem;
  color: var(--rock);
}

.page-about .about-toc__link:hover {
  color: var(--ink);
}

.page-about .about-toc__link[data-active] {
  color: var(--ink);
  border-bottom-color: var(--clay);
}

.page-about .about-toc__link[data-active] .num {
  color: var(--clay);
}

/* ---------- 章节骨架 ---------- */

.page-about .about-chapter__grid {
  row-gap: var(--about-gap);
}

.page-about .about-chapter__aside .display-2 {
  margin: .6rem 0 0;
  font-weight: 200;
  letter-spacing: -.02em;
  line-height: 1.12;
}

.page-about .about-chapter__aside .note {
  margin-top: 1.1rem;
}

.page-about .note--on-dark {
  border-left-color: var(--line-dark);
  color: var(--about-body-dark);
}

.page-about .about-chapter__body > * + * {
  margin-top: var(--about-gap-lg);
}

/* ---------- 时间线 ---------- */

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

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: .55rem;
  bottom: .55rem;
  width: 2px;
  background: var(--line-strong);
}

.page-about .about-timeline__item {
  position: relative;
  padding: 0 0 2.25rem 2.25rem;
}

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

.page-about .about-timeline__dot {
  position: absolute;
  left: 0;
  top: .4rem;
  width: 16px;
  height: 16px;
  background: var(--paper);
  border: 2px solid var(--clay);
}

.page-about .about-timeline__idx {
  margin: 0;
  font-size: .75rem;
  letter-spacing: .12em;
  color: var(--rock);
}

.page-about .about-timeline__title {
  margin: .35rem 0 .6rem;
  font-size: 1.375rem;
  font-weight: 400;
  letter-spacing: -.01em;
  color: var(--ink);
}

.page-about .about-timeline__text {
  margin: 0;
  max-width: 44ch;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--about-body-light);
}

.page-about .about-timeline__more {
  margin-top: .9rem;
  border: var(--about-hair);
  background: var(--paper);
  padding: 0 1rem;
  max-width: 46ch;
}

.page-about .about-timeline__more summary {
  display: flex;
  align-items: baseline;
  gap: .5rem;
  padding: .75rem 0;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-mono);
  font-size: .8125rem;
  letter-spacing: .03em;
  color: var(--clay);
}

.page-about .about-timeline__more summary::-webkit-details-marker {
  display: none;
}

.page-about .about-timeline__more summary::before {
  content: "+";
  font-size: 1rem;
  line-height: 1;
  color: var(--clay);
}

.page-about .about-timeline__more[open] summary::before {
  content: "−";
}

.page-about .about-timeline__more p {
  margin: 0 0 .95rem;
  font-size: .9375rem;
  line-height: 1.85;
  color: var(--about-body-light);
}

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

/* ---------- 流水线 ---------- */

.page-about .about-flow {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-flow__step {
  position: relative;
  display: grid;
  grid-template-columns: 2.75rem minmax(0, 1fr);
  gap: 0 1.25rem;
  padding: 1.5rem 0 1.75rem;
  border-top: 1px solid var(--line-dark);
}

.page-about .about-flow__step::after {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: 2.5rem;
  height: 2px;
  background: var(--cyan);
}

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

.page-about .about-flow__idx {
  grid-column: 1;
  padding-top: .2rem;
  font-size: .8125rem;
  letter-spacing: .1em;
  color: var(--cyan);
}

.page-about .about-flow__body {
  grid-column: 2;
  min-width: 0;
}

.page-about .about-flow__title {
  margin: 0;
  font-size: 1.1875rem;
  font-weight: 400;
  letter-spacing: -.005em;
  color: var(--warm);
}

.page-about .about-flow__text {
  margin: .55rem 0 0;
  max-width: 48ch;
  font-size: .9375rem;
  line-height: 1.85;
  color: var(--about-body-dark);
}

.page-about .about-flow__time {
  margin: .7rem 0 0;
  font-family: var(--font-mono);
  font-size: .75rem;
  letter-spacing: .06em;
  color: var(--orange-soft);
}

.page-about .about-flow__figure {
  margin: var(--about-gap-lg) 0 0;
}

/* ---------- 赛区 ---------- */

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

.page-about .about-map {
  display: block;
  width: 100%;
  height: auto;
  box-sizing: border-box;
  padding: clamp(.5rem, 2vw, 1.5rem);
  background: var(--navy);
  border: 1px solid var(--line-cyan);
}

.page-about .about-map__links line {
  stroke: rgba(47, 216, 208, .22);
  stroke-width: 1;
}

.page-about .about-map__node {
  fill: var(--cyan-deep);
  stroke: var(--cyan);
  stroke-width: 1.5;
  transform-box: fill-box;
  transform-origin: center;
  cursor: pointer;
  transition: transform var(--ease), fill var(--ease), stroke var(--ease);
}

.page-about .about-map__node--wide {
  fill: var(--cyan);
}

.page-about .about-map__node:hover,
.page-about .about-map__node:focus-visible {
  transform: scale(1.45);
  fill: var(--orange);
  stroke: var(--orange-soft);
}

.page-about .about-map__legend {
  margin: .75rem 0 0;
  font-family: var(--font-mono);
  font-size: .75rem;
  line-height: 1.8;
  letter-spacing: .02em;
  color: var(--rock);
  max-width: 62ch;
}

.page-about .about-regions__split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--about-gap);
}

.page-about .about-regions__block {
  border-left: 2px solid var(--clay);
  padding-left: 1.1rem;
}

.page-about .about-regions__heading {
  margin: 0 0 .5rem;
  font-size: 1.0625rem;
  font-weight: 500;
  letter-spacing: -.005em;
  color: var(--ink);
}

.page-about .about-regions__text {
  margin: 0;
  max-width: 46ch;
  font-size: .9375rem;
  line-height: 1.85;
  color: var(--about-body-light);
}

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

/* ---------- 字段与纠错 ---------- */

.page-about .about-glossary {
  margin: 0;
  border-top: var(--about-hair);
}

.page-about .about-glossary__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: .35rem 1.5rem;
  padding: 1.05rem 0;
  border-bottom: var(--about-hair);
}

.page-about .about-glossary__row dt {
  font-family: var(--font-mono);
  font-size: .875rem;
  letter-spacing: .02em;
  color: var(--ink);
}

.page-about .about-glossary__row dd {
  margin: 0;
  font-size: .9375rem;
  line-height: 1.85;
  color: var(--about-body-light);
}

.page-about .about-fix {
  border: var(--about-hair);
  background: var(--paper);
  padding: clamp(1.1rem, 3vw, 1.75rem);
}

.page-about .about-fix__heading {
  margin: 0 0 1.1rem;
  font-size: 1.125rem;
  font-weight: 500;
  letter-spacing: -.005em;
  color: var(--ink);
}

.page-about .about-fix__steps {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-fix__step {
  display: grid;
  grid-template-columns: 1.75rem minmax(0, 1fr);
  gap: .75rem;
  align-items: baseline;
  padding: .7rem 0;
  border-top: var(--about-hair);
}

.page-about .about-fix__step:first-child {
  border-top: 0;
}

.page-about .about-fix__num {
  font-size: .8125rem;
  color: var(--clay);
  letter-spacing: .06em;
}

.page-about .about-fix__step p {
  margin: 0;
  font-size: .9375rem;
  line-height: 1.8;
  color: var(--about-body-light);
}

.page-about .about-fix__foot {
  margin: 1.1rem 0 0;
  padding-top: 1rem;
  border-top: var(--about-hair);
  font-size: .9375rem;
  line-height: 1.85;
  color: var(--about-body-light);
}

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

.page-about .about-link:hover {
  color: var(--ink);
}

.page-about .about-link--on-dark {
  color: var(--cyan);
}

.page-about .about-link--on-dark:hover {
  color: var(--orange-soft);
}

/* ---------- 团队 ---------- */

.page-about .about-team {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line);
  border: var(--about-hair);
}

.page-about .about-team__cell {
  background: var(--paper);
  padding: 1.25rem 1.15rem 1.4rem;
}

.page-about .about-team__cell .stat__num {
  display: block;
  font-size: 2.75rem;
  font-weight: 600;
  line-height: 1;
  color: var(--clay);
}

.page-about .about-team__cell .stat__label {
  display: block;
  margin-top: .55rem;
  font-size: .875rem;
  letter-spacing: .02em;
  color: var(--ink);
}

.page-about .about-team__desc {
  margin: .65rem 0 0;
  font-size: .875rem;
  line-height: 1.8;
  color: var(--rock);
}

.page-about .about-team__note {
  margin-top: var(--about-gap);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1rem;
}

.page-about .about-team__note p {
  margin: 0;
  max-width: 52ch;
  font-size: .9375rem;
  line-height: 1.9;
  color: var(--about-body-light);
}

/* ---------- 备案 ---------- */

.page-about .about-credentials {
  padding-bottom: clamp(2.5rem, 7vw, 4.5rem);
}

.page-about .about-cred {
  margin: 0;
  border-top: var(--about-hair-dark);
}

.page-about .about-cred__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: .3rem 1.5rem;
  padding: .95rem 0;
  border-bottom: var(--about-hair-dark);
}

.page-about .about-cred__row dt {
  font-size: .8125rem;
  letter-spacing: .06em;
  color: rgba(244, 239, 230, .55);
}

.page-about .about-cred__row dd {
  margin: 0;
  font-size: .9375rem;
  line-height: 1.8;
  color: var(--warm);
}

.page-about .about-cred__row dd.num {
  letter-spacing: .02em;
}

.page-about .about-cred__foot {
  margin: var(--about-gap) 0 0;
  max-width: 58ch;
  font-size: .9375rem;
  line-height: 1.9;
  color: var(--about-body-dark);
}

.page-about .about-next {
  margin-top: var(--about-gap-lg);
  padding-top: 1.5rem;
  border-top: 1px solid var(--line-cyan);
}

.page-about .about-next__label {
  margin: 0 0 1rem;
}

.page-about .about-next__links {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

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

@media (min-width: 900px) {
  .page-about .about-chapter__grid {
    column-gap: clamp(2rem, 5vw, 4rem);
  }

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

  .page-about .about-hero__grid {
    align-items: end;
  }

  .page-about .about-hero__side {
    padding-bottom: .35rem;
  }

  .page-about .about-glossary__row,
  .page-about .about-cred__row {
    grid-template-columns: 12rem minmax(0, 1fr);
    align-items: baseline;
  }
}

@media (max-width: 560px) {
  .page-about .about-hero__fact dd {
    font-size: 1.5rem;
  }

  .page-about .about-timeline__item {
    padding-left: 1.9rem;
  }

  .page-about .about-flow__step {
    grid-template-columns: 1.9rem minmax(0, 1fr);
    gap: 0 .9rem;
  }

  .page-about .about-team__cell .stat__num {
    font-size: 2.25rem;
  }
}

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

  .page-about .about-map__node:hover,
  .page-about .about-map__node:focus-visible {
    transform: none;
  }
}