.page-about {
  --about-hair: rgba(38, 68, 95, 0.9);
  background: var(--ink);
  color: var(--paper);
  font-family: var(--sans);
  padding-top: var(--header-h);
}

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

/* ---------- 面包屑与眉标 ---------- */
.page-about .crumbs__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  margin: 0 0 28px;
  padding: 0;
  list-style: none;
  font-size: 13px;
  color: var(--gray);
}

.page-about .crumbs__item + .crumbs__item::before {
  content: "/";
  margin-right: 8px;
  color: var(--steel);
}

.page-about .crumbs__item a {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 160ms var(--ease), color 160ms var(--ease);
}

.page-about .crumbs__item a:hover,
.page-about .crumbs__item a:focus-visible {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

.page-about .eyebrow {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: baseline;
  margin: 0 0 18px;
  color: var(--mist);
}

.page-about .eyebrow .mono {
  color: var(--amber);
  letter-spacing: 0.08em;
}

.page-about .eyebrow__sep {
  color: var(--steel);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: 40px 0 56px;
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, var(--about-hair) 1px, transparent 1px),
    linear-gradient(to bottom, var(--about-hair) 1px, transparent 1px);
  background-size: 76px 76px;
  opacity: 0.16;
  pointer-events: none;
}

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

.page-about .about-hero__title {
  margin: 0 0 20px;
  font-size: clamp(2rem, 7.4vw, 3.5rem);
  font-weight: 800;
  line-height: 1.14;
  letter-spacing: -0.02em;
  color: var(--paper);
  max-width: 22ch;
}

.page-about .about-hero__lede {
  margin: 0;
  max-width: 46ch;
  color: var(--mist);
  font-size: 17px;
  line-height: 1.78;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

/* ---------- 数字条 ---------- */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 40px 0 0;
  padding: 0;
  list-style: none;
  background: var(--steel);
  border-top: 1px solid var(--steel);
  border-bottom: 1px solid var(--steel);
}

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

.page-about .about-stat a {
  display: block;
  height: 100%;
  padding: 16px 14px 18px;
  background: var(--ink);
  color: inherit;
  text-decoration: none;
  transition: background 160ms var(--ease), box-shadow 160ms var(--ease);
}

.page-about .about-stat a:hover,
.page-about .about-stat a:focus-visible {
  background: var(--hull);
  box-shadow: inset 3px 0 0 var(--amber);
}

.page-about .about-stat__num {
  display: block;
  font-family: var(--mono);
  font-size: 28px;
  line-height: 1.1;
  letter-spacing: 0.02em;
  color: var(--amber);
}

.page-about .about-stat__label {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  color: var(--gray);
}

/* ---------- 章节骨架 ---------- */
.page-about .about-band {
  padding: 56px 0;
}

.page-about .chapter {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
  min-width: 0;
}

.page-about .chapter__aside {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  align-items: baseline;
  padding-left: 14px;
  border-left: 2px solid var(--steel);
}

.page-about .chapter__no {
  font-size: 30px;
  line-height: 1;
  color: var(--amber);
  letter-spacing: 0.02em;
}

.page-about .chapter__year {
  font-size: 13px;
  color: var(--gray);
  letter-spacing: 0.04em;
}

.page-about .chapter__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .chapter__tag {
  padding: 3px 8px;
  border: 1px solid var(--steel);
  border-radius: 2px;
  font-size: 12px;
  color: var(--mist);
  white-space: nowrap;
}

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

.page-about .chapter__title {
  margin: 0 0 22px;
  font-size: clamp(1.45rem, 4.6vw, 2rem);
  font-weight: 800;
  line-height: 1.28;
  letter-spacing: -0.01em;
  color: inherit;
}

.page-about .chapter__title::before {
  content: "";
  display: block;
  width: 40px;
  height: 3px;
  margin-bottom: 16px;
  background: var(--amber);
}

.page-about .chapter__body p {
  max-width: 68ch;
  margin: 0 0 1.15em;
  font-size: 16.5px;
  line-height: 1.78;
  color: var(--mist);
}

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

.page-about .chapter__body a {
  color: var(--amber-soft);
  text-decoration: none;
  border-bottom: 1px solid rgba(245, 165, 36, 0.45);
  transition: color 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .chapter__body a:hover,
.page-about .chapter__body a:focus-visible {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

/* ---------- 图片与说明 ---------- */
.page-about .fig {
  margin: 32px 0 0;
  min-width: 0;
}

.page-about .fig img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--steel);
  border-radius: 2px;
  background: var(--hull);
}

.page-about .figcap {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--gray);
}

/* ---------- 时间线 ---------- */
.page-about .stages {
  position: relative;
  margin: 32px 0 0;
  padding: 0 0 0 30px;
  list-style: none;
}

.page-about .stages::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 10px;
  bottom: 10px;
  width: 2px;
  background: var(--steel);
}

.page-about .stage {
  position: relative;
  padding-bottom: 26px;
  outline: none;
}

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

.page-about .stage::before {
  content: "";
  position: absolute;
  left: -30px;
  top: 5px;
  width: 16px;
  height: 16px;
  border-radius: 2px;
  background: var(--amber);
  box-shadow: 0 0 0 3px var(--ink);
  transition: box-shadow 160ms var(--ease);
}

.page-about .stage--now::before {
  background: var(--ink);
  border: 2px solid var(--amber);
  width: 14px;
  height: 14px;
}

.page-about .stage:hover::before,
.page-about .stage:focus::before,
.page-about .stage:focus-within::before {
  box-shadow: 0 0 0 3px var(--ink), 0 0 0 5px rgba(245, 165, 36, 0.4);
}

.page-about .stage__year {
  display: block;
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--amber);
}

.page-about .stage__title {
  margin: 4px 0 6px;
  font-size: 17px;
  font-weight: 500;
  line-height: 1.45;
  color: var(--paper);
}

.page-about .stage__text {
  max-width: 60ch;
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--mist);
}

.page-about .stage__extra {
  max-height: 0;
  overflow: hidden;
  transition: max-height 220ms var(--ease);
}

.page-about .stage:hover .stage__extra,
.page-about .stage:focus .stage__extra,
.page-about .stage:focus-within .stage__extra {
  max-height: 6em;
}

.page-about .stage__extra p {
  margin: 8px 0 0;
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--gray);
}

/* ---------- 团队 ---------- */
.page-about .team-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
  min-width: 0;
}

.page-about .team-split__figure {
  margin-top: 0;
}

/* ---------- 合作生态（浅色段落） ---------- */
.page-about .about-band--paper {
  background: var(--paper);
  color: var(--ink);
}

.page-about .about-band--paper .chapter__aside {
  border-left-color: rgba(38, 68, 95, 0.35);
}

.page-about .about-band--paper .chapter__year {
  color: #56687a;
}

.page-about .about-band--paper .chapter__tag {
  border-color: rgba(38, 68, 95, 0.3);
  color: var(--hull);
}

.page-about .about-band--paper .chapter__body p {
  color: var(--hull);
}

.page-about .about-band--paper .chapter__body a {
  color: #a1662a;
  border-bottom-color: rgba(161, 102, 42, 0.4);
}

.page-about .partner-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  margin-top: 32px;
}

.page-about .partner-card {
  min-width: 0;
  padding: 20px 18px 22px;
  background: #ffffff;
  border: 1px solid rgba(38, 68, 95, 0.22);
  border-radius: 2px;
  transition: transform 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .partner-card:hover {
  transform: translateY(-2px);
  border-color: var(--amber);
}

.page-about .partner-card__scene {
  margin: 0 0 10px;
  font-size: 18px;
  font-weight: 800;
  letter-spacing: 0.02em;
  color: var(--ink);
}

.page-about .partner-card__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: #3c536b;
}

/* ---------- 承诺 ---------- */
.page-about .promise-list {
  margin: 8px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .promise {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 22px 0;
  border-top: 1px solid var(--steel);
  transition: border-color 160ms var(--ease);
}

.page-about .promise:hover {
  border-top-color: var(--amber);
}

.page-about .promise:last-child {
  border-bottom: 1px solid var(--steel);
}

.page-about .promise__no {
  font-size: 24px;
  line-height: 1;
  color: var(--amber);
  letter-spacing: 0.04em;
}

.page-about .promise__title {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 500;
  line-height: 1.5;
  color: var(--paper);
}

.page-about .promise__text {
  max-width: 66ch;
  margin: 0;
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--mist);
}

/* ---------- 节点 ---------- */
.page-about .nodes-figure img {
  filter: saturate(0.75);
}

/* ---------- 结尾 ---------- */
.page-about .about-cta {
  padding-bottom: 72px;
}

.page-about .about-cta__card {
  padding: 32px 22px 34px;
  background: var(--hull);
  border: 1px solid var(--steel);
  border-radius: 2px;
}

.page-about .about-cta__title {
  margin: 0 0 12px;
  font-size: clamp(1.3rem, 4.2vw, 1.7rem);
  font-weight: 800;
  line-height: 1.35;
  color: var(--paper);
}

.page-about .about-cta__text {
  max-width: 58ch;
  margin: 0 0 22px;
  font-size: 16px;
  line-height: 1.75;
  color: var(--mist);
}

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

/* ---------- 焦点可见性 ---------- */
.page-about a:focus-visible,
.page-about .stage:focus-visible,
.page-about .stage:focus {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
}

/* ---------- 平板 ---------- */
@media (min-width: 720px) {
  .page-about .about-hero {
    padding: 56px 0 72px;
  }

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

  .page-about .about-stat a {
    padding: 20px 18px 22px;
  }

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

  .page-about .promise {
    grid-template-columns: 72px minmax(0, 1fr);
    gap: 20px;
    align-items: start;
  }

  .page-about .about-cta__card {
    padding: 44px 40px 46px;
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 960px) {
  .page-about .about-band {
    padding: 88px 0;
  }

  .page-about .chapter {
    grid-template-columns: minmax(0, 3fr) minmax(0, 9fr);
    gap: 48px;
  }

  .page-about .chapter__aside {
    position: sticky;
    top: calc(var(--header-h) + 28px);
    align-self: start;
    flex-direction: column;
    gap: 10px;
    padding-left: 16px;
  }

  .page-about .chapter__no {
    font-size: 40px;
  }

  .page-about .chapter__tags {
    margin-top: 4px;
  }

  .page-about .team-split {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 40px;
  }

  .page-about .team-split__figure {
    margin-top: 48px;
  }

  .page-about .partner-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 18px;
  }

  .page-about .partner-card:nth-child(2) {
    margin-top: 24px;
  }

  .page-about .partner-card:nth-child(4) {
    margin-top: 48px;
  }

  .page-about .about-cta {
    padding-bottom: 96px;
  }
}

/* ---------- 触屏设备：展开不必依赖悬停 ---------- */
@media (hover: none) {
  .page-about .stage__extra {
    max-height: none;
    overflow: visible;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .stage__extra,
  .page-about .partner-card,
  .page-about .about-stat a,
  .page-about .promise {
    transition: none;
  }

  .page-about .partner-card:hover {
    transform: none;
  }
}