.page-about {
  --about-rail-w: 172px;
  --about-pause: 56px;
  background: var(--mist);
  color: var(--rock);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding: 28px 0 0;
  background:
    linear-gradient(180deg, rgba(20, 106, 140, .07) 0%, rgba(243, 246, 247, 0) 62%),
    var(--mist);
}

.page-about .about-hero__head {
  max-width: 900px;
  margin-top: 24px;
}

.page-about .about-hero h1 {
  margin: 12px 0 20px;
}

.page-about .about-hero__lead {
  max-width: 680px;
  color: var(--rock);
}

.page-about .about-hero__marks {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin: 36px 0 0;
  padding: 18px 0 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.page-about .about-hero__mark {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .about-hero__mark span {
  font-size: 30px;
  line-height: 1;
  letter-spacing: -.03em;
  color: var(--lake-deep);
}

.page-about .about-hero__mark em {
  font-style: normal;
  font-size: 13px;
  line-height: 1.5;
  color: var(--rock);
}

.page-about .about-hero__figure {
  margin-top: 44px;
}

/* ---------- 图片框 ---------- */

.page-about .about-figure {
  position: relative;
  margin: 0;
  border: 1px solid var(--line);
  background:
    repeating-linear-gradient(0deg, rgba(174, 186, 192, .12) 0 1px, transparent 1px 6px),
    linear-gradient(150deg, var(--lake-deep) 0%, var(--lake) 100%);
  overflow: hidden;
}

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

.page-about .about-figure--hero .about-figure__img {
  aspect-ratio: 16 / 9;
}

.page-about .about-figure--chart .about-figure__img {
  aspect-ratio: 1 / 1;
}

.page-about .about-figure--desk .about-figure__img {
  aspect-ratio: 4 / 3;
}

.page-about .about-figure__cap {
  display: block;
  padding: 8px 12px;
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--mist);
  background: var(--ink);
  border-top: 1px solid var(--line-dark);
}

/* ---------- 叙事骨架 ---------- */

.page-about .about-story {
  padding-top: var(--about-pause);
}

.page-about .story-col {
  min-width: 0;
}

.page-about .story-block {
  scroll-margin-top: calc(var(--topbar-h) + 24px);
}

.page-about .story-block--open {
  padding-top: 8px;
}

.page-about .story-block h2 {
  margin: 12px 0 18px;
}

.page-about .story-block__body p,
.page-about .story-block p {
  margin: 0 0 16px;
  font-size: 16px;
  line-height: 1.75;
  color: var(--rock);
}

.page-about .story-block__intro {
  max-width: 620px;
}

.page-about .story-block__tail {
  color: var(--rock);
}

.page-about .story-divider {
  height: 1px;
  margin: 44px 0;
  background: var(--line);
}

.page-about .idx {
  display: inline-block;
  font-size: 12px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--lake);
  padding-bottom: 4px;
  border-bottom: 2px solid var(--lime);
}

/* ---------- 年度条目 ---------- */

.page-about .era-list {
  margin-top: 32px;
}

.page-about .era {
  padding: 32px 0;
  border-top: 1px solid var(--line-soft);
  scroll-margin-top: calc(var(--topbar-h) + 24px);
}

.page-about .era:last-child {
  border-bottom: 1px solid var(--line-soft);
}

.page-about .era__head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 12px;
}

.page-about .era__num {
  font-size: 54px;
  line-height: .9;
  letter-spacing: -.04em;
  color: var(--lake-deep);
}

.page-about .era__count {
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--lake);
  padding: 3px 8px;
  border: 1px solid var(--line);
  white-space: nowrap;
}

.page-about .era__body h3 {
  margin: 0 0 10px;
}

.page-about .era__body > p {
  margin: 0 0 16px;
  line-height: 1.75;
}

.page-about .era__expand {
  margin-top: 14px;
}

/* ---------- 团队 ---------- */

.page-about .team-split {
  display: grid;
  gap: 24px;
}

.page-about .duty-list {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .duty-list__item {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .duty-list__k {
  flex: 0 0 auto;
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--lake-deep);
  min-width: 76px;
}

.page-about .duty-list__v {
  flex: 1 1 200px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--rock);
}

/* ---------- 互校流程 ---------- */

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

.page-about .flow-list__item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 12px;
  padding: 14px 0;
  border-bottom: 1px dashed var(--line);
}

.page-about .flow-list__item:last-child {
  border-bottom: 0;
}

.page-about .flow-list__k {
  font-size: 13px;
  color: var(--term);
}

.page-about .flow-list__v {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--rock);
}

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

.page-about .dot-list li {
  position: relative;
  padding: 7px 0 7px 18px;
  font-size: 14px;
  line-height: 1.65;
  color: var(--rock);
}

.page-about .dot-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 15px;
  width: 5px;
  height: 5px;
  background: var(--lake);
}

/* ---------- 展开组图标状态 ---------- */

.page-about .expand[open] .expand__icon,
.page-about details[open] > .expand__trigger .expand__icon {
  color: var(--lake-deep);
  border-color: var(--lake);
  background: var(--lime);
}

/* ---------- 右侧时间线 ---------- */

.page-about .story-rail {
  margin-top: 32px;
}

.page-about .story-rail__title {
  margin: 0 0 12px;
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--rock-light);
}

.page-about .story-rail__list {
  display: flex;
  gap: 12px;
  margin: 0;
  padding: 0 0 6px;
  list-style: none;
  overflow-x: auto;
}

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

.page-about .story-rail__link {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 9px 14px;
  border: 1px solid var(--line);
  background: rgba(243, 246, 247, .7);
  color: var(--rock);
  text-decoration: none;
  white-space: nowrap;
  transition: border-color .25s var(--ease), color .25s var(--ease);
}

.page-about .story-rail__link::after {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--lime);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform .25s var(--ease);
}

.page-about .story-rail__link:hover,
.page-about .story-rail__link:focus-visible {
  border-color: var(--lake);
  color: var(--lake-deep);
}

.page-about .story-rail__link:hover::after,
.page-about .story-rail__link:focus-visible::after {
  transform: scaleY(1);
}

.page-about .story-rail__year {
  font-size: 14px;
  letter-spacing: .04em;
}

.page-about .story-rail__n {
  font-size: 12px;
  color: var(--rock-light);
}

.page-about .story-rail__foot {
  margin: 12px 0 0;
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--rock-light);
}

/* ---------- 结尾数字带 ---------- */

.page-about .about-band {
  margin-top: var(--about-pause);
  padding: 0;
  background: var(--mist);
}

.page-about .about-band__grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--lake);
  border-bottom: 1px solid var(--lake);
}

.page-about .about-band__cell {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 22px 16px;
  border-right: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-band__num {
  font-size: 44px;
  line-height: .9;
  letter-spacing: -.04em;
  color: var(--lake-deep);
}

.page-about .about-band__year {
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--lake);
}

.page-about .about-band__label {
  font-size: 13px;
  line-height: 1.55;
  color: var(--rock);
}

/* ---------- 结尾入口 ---------- */

.page-about .about-cta {
  padding-top: 48px;
}

.page-about .about-cta__box {
  display: grid;
  gap: 24px;
  padding: 32px 24px;
  background: var(--lake-deep);
  border-left: 3px solid var(--lime);
}

.page-about .about-cta__copy h2 {
  margin: 0 0 12px;
  color: var(--mist);
}

.page-about .about-cta__copy p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--rock-light);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-content: start;
}

/* ---------- 响应式 ---------- */

@media (min-width: 700px) {
  .page-about .about-hero__mark span {
    font-size: 38px;
  }

  .page-about .era__num {
    font-size: 68px;
  }

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

  .page-about .about-band__cell {
    border-bottom: 0;
  }

  .page-about .about-band__cell:last-child {
    border-right: 0;
  }

  .page-about .team-split {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    gap: 32px;
    align-items: start;
  }

  .page-about .about-cta__box {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: center;
    padding: 40px 36px;
  }

  .page-about .about-cta__actions {
    flex-direction: column;
    align-items: stretch;
  }
}

@media (min-width: 1024px) {
  .page-about .story-shell {
    display: grid;
    grid-template-columns: minmax(0, 1fr) var(--about-rail-w);
    gap: 64px;
  }

  .page-about .story-col {
    grid-column: 1;
    grid-row: 1;
  }

  .page-about .story-rail {
    grid-column: 2;
    grid-row: 1;
    position: sticky;
    top: calc(var(--topbar-h) + 28px);
    align-self: start;
    margin-top: 8px;
    padding-left: 0;
  }

  .page-about .story-rail__title {
    padding-left: 18px;
  }

  .page-about .story-rail__list {
    display: block;
    overflow: visible;
    padding: 0;
    border-left: 1px solid var(--line);
  }

  .page-about .story-rail__item {
    display: block;
  }

  .page-about .story-rail__link {
    justify-content: space-between;
    width: 100%;
    padding: 13px 0 13px 18px;
    border: 0;
    border-bottom: 1px solid var(--line-soft);
    background: transparent;
  }

  .page-about .story-rail__link::before {
    content: "";
    position: absolute;
    left: -3px;
    top: 50%;
    width: 5px;
    height: 5px;
    margin-top: -2.5px;
    background: var(--rock-light);
    transition: background .25s var(--ease);
  }

  .page-about .story-rail__link:hover::before,
  .page-about .story-rail__link:focus-visible::before {
    background: var(--lime);
  }

  .page-about .story-rail__foot {
    padding-left: 18px;
  }

  .page-about .era {
    padding: 44px 0;
  }

  .page-about .story-divider {
    margin: 56px 0;
  }
}

@media (min-width: 1200px) {
  .page-about .about-hero {
    padding-top: 44px;
  }

  .page-about .era__num {
    font-size: 80px;
  }

  .page-about .about-band__num {
    font-size: 54px;
  }
}

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