.page-about {
  --tl-gutter: 48px;
  --tl-gap: 16px;
  position: relative;
  overflow-x: clip;
  color: var(--warm);
}

.page-about .about-ruler {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: 12px;
  z-index: 2;
  pointer-events: none;
  background-image: repeating-linear-gradient(to bottom, var(--cream) 0 1px, transparent 1px 8px);
  opacity: .16;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: 84px 0 60px;
  overflow: hidden;
  background:
    radial-gradient(120% 88% at 84% 4%, rgba(200, 240, 42, .10), transparent 58%),
    linear-gradient(180deg, var(--ink-700) 0%, var(--ink-900) 76%);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: -20%;
  right: -26%;
  width: 66%;
  height: 122%;
  pointer-events: none;
  border-radius: var(--radius-lg);
  transform: rotate(-8deg);
  background: linear-gradient(158deg, rgba(46, 107, 223, .24), rgba(200, 240, 42, .10) 46%, transparent 78%);
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__title {
  margin: 16px 0 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(36px, 9.6vw, 98px);
  line-height: .98;
  letter-spacing: .005em;
  color: var(--warm);
}

.page-about .about-hero__lede {
  margin: 22px 0 0;
  max-width: 36em;
  color: var(--cream);
}

.page-about .about-hero__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px 16px;
  margin-top: 40px;
  padding-top: 26px;
  border-top: 1px solid rgba(217, 212, 196, .22);
}

.page-about .about-hero__stats .stat__label {
  margin: 0;
}

.page-about .about-hero__stats .stat__value {
  margin: 6px 0 0;
  font-family: var(--font-mono);
  letter-spacing: .02em;
}

/* ---------- 开篇 ---------- */
.page-about .about-origin {
  padding-top: 76px;
}

.page-about .about-origin__panel {
  align-self: start;
  border-radius: var(--radius-lg);
}

.page-about .about-steps {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 14px;
}

.page-about .about-steps__item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 10px;
  align-items: baseline;
  padding-bottom: 12px;
  border-bottom: 1px dashed rgba(217, 212, 196, .2);
}

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

.page-about .about-steps__num {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--lime);
  letter-spacing: .06em;
}

.page-about .about-steps__text {
  font-size: 15px;
  line-height: 1.6;
  color: var(--warm);
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline__banner {
  margin: 28px 0 0;
}

.page-about .about-timeline__banner .media-frame__img,
.page-about .about-source__figure .media-frame__img,
.page-about .about-team__figure .media-frame__img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: var(--radius-md);
}

.page-about .about-timeline__list {
  position: relative;
  display: grid;
  gap: 26px;
  margin-top: 40px;
}

.page-about .about-timeline__list::before {
  content: "";
  position: absolute;
  left: calc(var(--tl-gutter) + var(--tl-gap) / 2);
  top: 14px;
  bottom: 14px;
  width: 1px;
  background: linear-gradient(180deg, rgba(217, 212, 196, .06), rgba(217, 212, 196, .42) 10%, rgba(217, 212, 196, .42) 90%, rgba(217, 212, 196, .06));
}

.page-about .tl-item {
  position: relative;
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  top: 15px;
  left: calc(var(--tl-gutter) + var(--tl-gap) / 2 - 4px);
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink-500);
  box-shadow: 0 0 0 1px rgba(217, 212, 196, .5);
}

.page-about .tl-item:last-child::before {
  background: var(--lime);
  box-shadow: 0 0 0 1px rgba(200, 240, 42, .45);
}

.page-about .tl-item__summary {
  position: relative;
  display: grid;
  grid-template-columns: var(--tl-gutter) minmax(0, 1fr);
  gap: var(--tl-gap);
  align-items: start;
  padding: 6px 34px 6px 0;
  cursor: pointer;
  list-style: none;
}

.page-about .tl-item__summary::-webkit-details-marker {
  display: none;
}

.page-about .tl-item__summary::after {
  content: "+";
  position: absolute;
  top: 4px;
  right: 0;
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--lime);
}

.page-about .tl-item[open] .tl-item__summary::after {
  content: "\2212";
}

.page-about .tl-item__summary:focus-visible {
  outline: 2px solid var(--lime);
  outline-offset: 4px;
  border-radius: var(--radius-sm);
}

.page-about .tl-year {
  display: block;
  text-align: right;
  font-family: var(--font-mono);
  font-size: 22px;
  line-height: 1.1;
  letter-spacing: .02em;
  color: var(--cream);
  transition: color 220ms var(--ease-out);
}

.page-about .tl-item[open] .tl-year {
  color: var(--lime);
}

.page-about .tl-item:nth-child(1) .tl-year { font-size: 20px; }
.page-about .tl-item:nth-child(2) .tl-year { font-size: 23px; }
.page-about .tl-item:nth-child(3) .tl-year { font-size: 26px; }
.page-about .tl-item:nth-child(4) .tl-year { font-size: 30px; }
.page-about .tl-item:nth-child(5) .tl-year { font-size: 34px; color: var(--lime); }

.page-about .tl-item__head {
  display: block;
}

.page-about .tl-item__title {
  display: block;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 20px;
  line-height: 1.25;
  color: var(--warm);
}

.page-about .tl-item__hint {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  letter-spacing: .02em;
  color: var(--stone);
}

.page-about .tl-item__body {
  margin: 14px 0 0 calc(var(--tl-gutter) + var(--tl-gap));
  padding: 16px 18px;
  border-radius: var(--radius-md);
  border-left: 2px solid rgba(200, 240, 42, .55);
  background: rgba(18, 58, 49, .55);
}

.page-about .tl-item__body p {
  margin: 0;
  font-size: 15px;
}

/* ---------- 数据来源 ---------- */
.page-about .about-source__grid {
  align-items: center;
}

.page-about .about-source__diagram {
  padding: 18px;
  border-radius: var(--radius-lg);
  border: 1px solid rgba(217, 212, 196, .18);
  background: linear-gradient(160deg, var(--ink-700), var(--ink-900));
}

.page-about .about-source__diagram svg {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .about-source__figure {
  margin: 34px 0 0;
}

/* ---------- 团队 ---------- */
.page-about .about-team__grid {
  align-items: start;
}

.page-about .share-list {
  display: grid;
  gap: 22px;
}

.page-about .share-item__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
}

.page-about .share-item__name {
  font-size: 15px;
  color: var(--warm);
}

.page-about .share-item__num {
  font-family: var(--font-mono);
  font-size: 17px;
  letter-spacing: .02em;
  color: var(--lime);
}

.page-about .share-bar {
  margin-top: 8px;
  height: 10px;
  border-radius: var(--radius-pill);
  background: rgba(217, 212, 196, .12);
  overflow: hidden;
}

.page-about .share-bar__fill {
  display: block;
  height: 100%;
  border-radius: inherit;
}

.page-about .share-bar__fill--data { width: 43%; background: var(--ink-500); }
.page-about .share-bar__fill--tech { width: 36%; background: var(--blue); }
.page-about .share-bar__fill--content { width: 21%; background: var(--clay); }

.page-about .share-item__note {
  margin: 8px 0 0;
  font-size: 13px;
  line-height: 1.6;
  color: var(--stone);
}

.page-about .about-team__prose {
  margin-top: 28px;
}

.page-about .about-team__figure {
  margin: 30px 0 0;
}

.page-about .about-team__figure .media-frame__img {
  border-radius: var(--radius-lg);
}

/* ---------- 合作生态 ---------- */
.page-about .about-partners__list {
  margin: 0;
  align-self: start;
  padding: 6px 0;
  border-top: 1px solid rgba(217, 212, 196, .22);
}

.page-about .about-partners__list .data-list__row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px;
  padding: 13px 0;
  border-bottom: 1px solid rgba(217, 212, 196, .16);
}

.page-about .about-partners__list .data-list__key {
  font-size: 14px;
  color: var(--cream);
}

.page-about .about-partners__list .data-list__val {
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: .02em;
  color: var(--lime);
}

/* ---------- 下一步 ---------- */
.page-about .about-next__grid {
  align-items: start;
}

.page-about .about-next__side {
  align-self: start;
}

.page-about .about-next__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-next__contact {
  margin: 20px 0 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--cream);
}

/* ---------- 平板 / 桌面 ---------- */
@media (min-width: 760px) {
  .page-about .about-hero {
    padding: 108px 0 78px;
  }

  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 26px 24px;
    margin-top: 52px;
  }

  .page-about .about-timeline__list {
    gap: 34px;
    margin-top: 52px;
  }

  .page-about .tl-item__title {
    font-size: 24px;
  }

  .page-about .tl-item__body {
    padding: 20px 24px;
  }

  .page-about .about-source__figure,
  .page-about .about-team__figure {
    margin-top: 40px;
  }
}

@media (min-width: 980px) {
  .page-about {
    --tl-gutter: 112px;
    --tl-gap: 40px;
  }

  .page-about .about-ruler {
    width: 16px;
    opacity: .22;
  }

  .page-about .about-hero::before {
    width: 52%;
    right: -14%;
  }

  .page-about .about-hero__title {
    letter-spacing: .01em;
  }

  .page-about .tl-item:nth-child(1) .tl-year { font-size: 26px; }
  .page-about .tl-item:nth-child(2) .tl-year { font-size: 32px; }
  .page-about .tl-item:nth-child(3) .tl-year { font-size: 38px; }
  .page-about .tl-item:nth-child(4) .tl-year { font-size: 46px; }
  .page-about .tl-item:nth-child(5) .tl-year { font-size: 56px; }

  .page-about .tl-item__title {
    font-size: 28px;
  }

  .page-about .about-timeline__banner {
    margin-top: 36px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tl-year {
    transition: none;
  }
}