.page-about {
  --about-band-pad: clamp(22px, 4vw, 38px);
  background: var(--lake-white);
  color: var(--ink);
}

.page-about .about-crumbs {
  padding-top: 22px;
  padding-bottom: 4px;
  font-size: var(--s2);
  color: var(--muted);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(28px, 5vw, 54px) 0 clamp(34px, 6vw, 62px);
  background:
    radial-gradient(120% 92% at 84% 0%, rgba(14, 92, 122, 0.12) 0%, rgba(14, 92, 122, 0) 62%),
    radial-gradient(92% 84% at 2% 100%, rgba(31, 111, 99, 0.1) 0%, rgba(31, 111, 99, 0) 64%),
    var(--lake-white);
  border-bottom: 1px solid var(--rule);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(26px, 5vw, 50px);
  align-items: end;
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  letter-spacing: -0.02em;
  color: var(--blue-deep);
}

.page-about .about-hero__lede {
  margin-top: 20px;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .about-hero__rail {
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  background: var(--paper);
  padding: 22px;
  box-shadow: var(--shadow-card);
}

.page-about .about-hero__coord {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0;
  padding-bottom: 14px;
  border-bottom: 1px dashed var(--contour);
  color: var(--qing);
  font-size: var(--s2);
}

.page-about .about-hero__nums {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 18px;
  margin: 18px 0 0;
}

.page-about .about-hero__nums div {
  border-top: 1px solid var(--rule);
  padding-top: 10px;
  min-width: 0;
}

.page-about .about-hero__nums dt {
  font-size: var(--s1);
  letter-spacing: 0.04em;
  color: var(--muted);
}

.page-about .about-hero__nums dd {
  margin: 6px 0 0;
  font-size: var(--s5);
  line-height: 1.2;
  color: var(--blue-lake);
}

.page-about .about-hero__rail .annotation {
  display: block;
  margin-top: 18px;
  padding-top: 14px;
  border-top: 1px solid var(--rule);
}

/* ---------- 主体两栏 ---------- */
.page-about .about-body {
  padding: clamp(28px, 5vw, 54px) 0 clamp(46px, 8vw, 92px);
}

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

.page-about .about-index {
  background: var(--paper);
  border: 1px solid var(--rule);
  border-radius: var(--radius-sm);
  padding: 14px;
  min-width: 0;
}

.page-about .about-index__label {
  margin: 0 0 10px;
  font-size: var(--s1);
  letter-spacing: 0.12em;
  color: var(--muted);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0 0 4px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-index__link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 14px;
  border: 1px solid var(--rule);
  border-radius: 999px;
  background: #fff;
  color: var(--blue-deep);
  font-size: var(--s2);
  text-decoration: none;
  white-space: nowrap;
  transition: border-color 0.24s var(--ease), color 0.24s var(--ease);
}

.page-about .about-index__link .mono {
  font-size: var(--s1);
  color: var(--gold);
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  border-color: var(--gold);
  color: var(--red);
}

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

/* ---------- 章节 ---------- */
.page-about .about-chapter {
  position: relative;
  margin-bottom: clamp(32px, 5vw, 52px);
  padding-bottom: clamp(30px, 5vw, 50px);
  border-bottom: 1px dashed var(--contour);
}

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

.page-about .about-chapter__head {
  display: flex;
  align-items: flex-end;
  gap: 14px;
  margin-bottom: 18px;
}

.page-about .about-chapter__num {
  flex: none;
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(26px, 4vw, 36px);
  line-height: 0.9;
  letter-spacing: -0.02em;
  color: var(--contour);
}

.page-about .about-chapter__head .headline {
  margin: 0;
  color: var(--blue-deep);
}

.page-about .about-chapter__body p {
  margin: 0;
  font-size: var(--s3);
  line-height: 1.85;
  color: var(--ink);
  max-width: 62ch;
}

.page-about .about-chapter__body p + p {
  margin-top: 16px;
}

.page-about .about-chapter__body .lede {
  color: var(--muted);
}

.page-about .about-cols {
  display: grid;
  gap: 22px;
  margin-top: 4px;
}

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

/* ---------- 色带 ---------- */
.page-about .about-band {
  border-bottom: 0;
  border-radius: var(--radius);
  padding: var(--about-band-pad);
}

.page-about .about-band--sand {
  background: var(--sand);
}

.page-about .about-band--paper {
  background: var(--paper);
  border: 1px solid var(--rule);
}

.page-about .about-band--deep {
  background: linear-gradient(152deg, var(--blue-deep) 0%, var(--blue-lake) 78%);
  color: var(--lake-white);
  box-shadow: 0 30px 60px -42px rgba(10, 62, 85, 0.9);
}

.page-about .about-band--deep .headline,
.page-about .about-band--deep .about-chapter__body p {
  color: var(--lake-white);
}

.page-about .about-band--deep .about-chapter__num {
  color: rgba(245, 248, 248, 0.45);
}

.page-about .about-band--deep .annotation {
  color: rgba(245, 248, 248, 0.74);
}

/* ---------- 版本分段 ---------- */
.page-about .about-versions {
  margin-top: 22px;
}

.page-about .about-versions__bar {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--rule);
  scrollbar-width: thin;
}

.page-about .about-versions__bar .tab {
  white-space: nowrap;
  font-size: var(--s2);
}

.page-about .about-vpanel {
  padding-top: 22px;
  max-width: 68ch;
}

.page-about .about-vpanel__title {
  margin: 0 0 12px;
  font-size: var(--s5);
  font-weight: 700;
  line-height: 1.4;
  color: var(--blue-deep);
}

.page-about .about-vpanel__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 14px;
}

.page-about .about-vpanel__meta span {
  padding: 4px 11px;
  border: 1px solid rgba(14, 92, 122, 0.24);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.6);
  font-family: var(--font-mono);
  font-size: var(--s1);
  color: var(--qing);
}

.page-about .about-vpanel p {
  margin: 0;
  font-size: var(--s3);
  line-height: 1.85;
}

.page-about .about-timeline__note {
  margin: 26px 0 0;
  max-width: 60ch;
}

.page-about .about-timeline__note a {
  color: var(--blue-lake);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---------- 图表 ---------- */
.page-about .about-figure {
  margin: 20px 0 0;
}

.page-about .about-figure--wide {
  margin-top: 0;
  margin-bottom: 22px;
}

/* ---------- 岗位 ---------- */
.page-about .about-roles {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
}

.page-about .about-role {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 14px;
  padding: 16px 0;
  border-top: 1px solid var(--rule);
}

.page-about .about-role__num {
  padding-top: 5px;
  font-family: var(--font-mono);
  font-size: var(--s1);
  letter-spacing: 0.08em;
  color: var(--gold);
}

.page-about .about-role__name {
  margin: 0;
  font-size: var(--s4);
  font-weight: 700;
  color: var(--blue-deep);
}

.page-about .about-role__text {
  grid-column: 2;
  margin: 6px 0 0;
  font-size: var(--s3);
  line-height: 1.8;
  color: var(--muted);
  max-width: 58ch;
}

/* ---------- 服务版图 ---------- */
.page-about .about-map__stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 20px;
  margin: 4px 0 26px;
}

.page-about .about-map__stat {
  border-top: 2px solid var(--gold);
  padding-top: 12px;
  min-width: 0;
}

.page-about .about-map__num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(38px, 8vw, 60px);
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--lake-white);
}

.page-about .about-map__label {
  margin: 12px 0 0;
  font-size: var(--s2);
  line-height: 1.7;
  color: rgba(245, 248, 248, 0.78);
}

.page-about .about-map__note {
  margin: 0 0 18px;
  max-width: 40ch;
}

.page-about .about-map__cta {
  min-height: 46px;
}

/* ---------- 伙伴 ---------- */
.page-about .about-partners {
  margin-top: 22px;
}

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

.page-about .about-partner .card__path {
  margin-top: auto;
  padding-top: 12px;
  text-decoration: none;
}

.page-about .about-partners__note {
  margin-top: 22px;
}

.page-about .about-partners__cta {
  margin-top: 18px;
}

/* ---------- 资质 ---------- */
.page-about .about-creds {
  margin-top: 22px;
  display: grid;
  gap: 12px;
}

.page-about .about-cred {
  background: #fff;
  border: 1px solid var(--rule);
  border-radius: var(--radius-sm);
  padding: 0 20px;
}

.page-about .about-cred summary {
  position: relative;
  cursor: pointer;
  list-style: none;
  padding: 18px 34px 18px 0;
  font-size: var(--s4);
  font-weight: 700;
  color: var(--blue-deep);
}

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

.page-about .about-cred summary::after {
  content: "+";
  position: absolute;
  right: 2px;
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-mono);
  font-size: var(--s5);
  color: var(--gold);
}

.page-about .about-cred[open] summary::after {
  content: "−";
  color: var(--red);
}

.page-about .about-cred__body {
  border-top: 1px dashed var(--contour);
  padding-bottom: 20px;
}

.page-about .about-cred__body p {
  margin: 14px 0 0;
  font-size: var(--s3);
  line-height: 1.85;
  color: var(--muted);
  max-width: 60ch;
}

/* ---------- 下游入口 ---------- */
.page-about .about-next {
  background: var(--paper);
  border-top: 1px solid var(--rule);
  padding: clamp(40px, 7vw, 72px) 0 clamp(52px, 8vw, 88px);
}

.page-about .about-next .headline {
  margin: 0;
  color: var(--blue-deep);
}

.page-about .about-next__grid {
  display: grid;
  gap: 16px;
  margin-top: 26px;
}

.page-about .about-next__card {
  display: block;
  text-decoration: none;
  color: inherit;
  transition: transform 0.32s var(--ease), box-shadow 0.32s var(--ease);
}

.page-about .about-next__card:hover,
.page-about .about-next__card:focus-visible {
  transform: translateY(-4px);
  box-shadow: 0 26px 50px -34px rgba(10, 62, 85, 0.7);
}

/* ---------- 桌面布局 ---------- */
@media (min-width: 760px) {
  .page-about .about-next__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.6fr) minmax(280px, 0.9fr);
  }

  .page-about .about-layout {
    grid-template-columns: minmax(190px, 226px) minmax(0, 1fr);
    gap: 52px;
    align-items: start;
  }

  .page-about .about-index {
    position: sticky;
    top: 104px;
    padding: 20px 18px;
  }

  .page-about .about-index__list {
    flex-direction: column;
    gap: 2px;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-index__link {
    width: 100%;
    padding: 10px 8px 10px 14px;
    border: 0;
    border-left: 2px solid var(--rule);
    border-radius: 0;
    background: none;
    font-size: var(--s2);
  }

  .page-about .about-index__link:hover,
  .page-about .about-index__link:focus-visible {
    border-left-color: var(--red);
    background: rgba(200, 145, 46, 0.09);
  }

  .page-about .about-flow {
    padding-left: 34px;
    border-left: 1px dashed var(--contour);
  }

  .page-about .about-chapter::before {
    content: "";
    position: absolute;
    left: -39px;
    top: 12px;
    width: 9px;
    height: 9px;
    border-radius: 50%;
    background: var(--qing);
    box-shadow: 0 0 0 4px rgba(31, 111, 99, 0.16);
  }

  .page-about .about-chapter.about-band {
    padding-left: var(--about-band-pad);
  }

  .page-about .about-band--deep::before {
    background: var(--gold);
    box-shadow: 0 0 0 4px rgba(200, 145, 46, 0.2);
  }

  .page-about .about-cols {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 0.95fr);
    gap: 34px;
    align-items: start;
  }

  .page-about .about-cols__aside {
    padding-top: 6px;
  }

  .page-about .about-roles {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 40px;
  }

  .page-about .about-role:nth-child(-n + 2) {
    border-top: 1px solid var(--rule);
  }
}

@media (min-width: 1080px) {
  .page-about .about-next__grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

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

  .page-about .about-next__card:hover,
  .page-about .about-next__card:focus-visible {
    transform: none;
  }
}
</main>