.page-about {
  --about-pad: clamp(28px, 5vw, 64px);
  --about-rail-col: clamp(38px, 9vw, 52px);
  background: var(--c-field);
  color: var(--c-ice);
}

/* 面包屑 */
.page-about .breadcrumb {
  padding-top: 22px;
}

/* ============ 首屏 ============ */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: var(--about-pad) 0 calc(var(--about-pad) * 0.85);
  border-bottom: 1px solid var(--c-net);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: -30%;
  right: -14%;
  width: 60%;
  height: 170%;
  background: linear-gradient(
    112deg,
    transparent 0 44%,
    var(--c-pulse-08) 44% 45.4%,
    transparent 45.4% 56%,
    var(--c-strike-14) 56% 56.7%,
    transparent 56.7% 100%
  );
  pointer-events: none;
}

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

.page-about .eyebrow {
  color: var(--c-pulse);
}

.page-about .about-hero-title {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(34px, 7.2vw, 96px);
  line-height: 1.04;
  letter-spacing: -0.03em;
  color: var(--c-ice);
  overflow-wrap: break-word;
}

.page-about .hero-em {
  color: var(--c-pulse);
}

.page-about .about-hero-lead {
  max-width: 62ch;
  margin: 22px 0 0;
  font-size: 16.5px;
  line-height: 1.78;
  color: var(--c-ice);
}

.page-about .about-hero-sub {
  max-width: 60ch;
  margin: 12px 0 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--c-grey);
}

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

.page-about .btn-pulse {
  background: var(--c-pulse);
  border-color: var(--c-pulse);
  color: var(--c-ink);
  font-weight: 700;
  transition: background-color 120ms var(--ease), border-color 120ms var(--ease);
}

.page-about .btn-pulse:hover {
  background: var(--c-ice);
  border-color: var(--c-ice);
}

.page-about .btn-ghost {
  color: var(--c-ice);
  border-color: var(--c-net);
  transition: color 120ms var(--ease), border-color 120ms var(--ease);
}

.page-about .btn-ghost:hover {
  color: var(--c-pulse);
  border-color: var(--c-pulse);
}

.page-about .hero-facts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 22px 32px;
  margin: 40px 0 0;
  padding-top: 22px;
  border-top: 1px solid var(--c-net);
}

.page-about .hero-fact dt {
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--c-grey);
}

.page-about .hero-fact dd {
  margin: 9px 0 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(26px, 3.4vw, 42px);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1;
  color: var(--c-pulse);
}

/* ============ 时间轨道 ============ */
.page-about .about-track-section {
  padding: 0 0 var(--about-pad);
}

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

.page-about .track-node {
  display: grid;
  grid-template-columns: var(--about-rail-col) minmax(0, 1fr);
  gap: 14px;
  padding: 30px 0 36px;
  border-top: 1px solid var(--c-net);
}

.page-about .track-node:first-child {
  border-top: 0;
  padding-top: 40px;
}

.page-about .node-num {
  position: relative;
  display: block;
  padding-top: 5px;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(14px, 1.9vw, 20px);
  letter-spacing: 0.08em;
  color: var(--c-pulse);
}

.page-about .node-content {
  min-width: 0;
}

.page-about .node-title {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(23px, 3.3vw, 40px);
  line-height: 1.22;
  letter-spacing: -0.018em;
  color: var(--c-ice);
}

.page-about .node-text {
  max-width: 66ch;
  margin: 16px 0 0;
  font-size: 16.5px;
  line-height: 1.8;
  color: var(--c-ice);
}

.page-about .inline-link {
  color: var(--c-pulse);
  border-bottom: 1px solid var(--c-pulse-40);
  transition: border-color 120ms var(--ease);
}

.page-about .inline-link:hover {
  border-bottom-color: var(--c-pulse);
}

/* 旁注 */
.page-about .node-aside {
  max-width: 60ch;
  margin: 24px 0 0;
  padding: 14px 0 14px 16px;
  border-left: 2px solid var(--c-pulse);
  background: linear-gradient(90deg, var(--c-pulse-08), transparent 72%);
}

.page-about .aside-label {
  display: block;
  margin-bottom: 7px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--c-pulse);
}

.page-about .node-aside p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--c-grey);
}

/* 图片 */
.page-about .about-figure {
  margin: 26px 0 0;
  border: 1px solid var(--c-net);
  background: var(--c-stand);
  overflow: hidden;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.page-about .about-figure--band img {
  aspect-ratio: 2 / 1;
}

.page-about .about-figure figcaption {
  padding: 10px 14px;
  border-top: 1px solid var(--c-net);
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--c-grey);
}

/* 链路指标 */
.page-about .chain-list {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  border-top: 1px solid var(--c-net);
}

.page-about .chain-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 3px;
  padding: 13px 0;
  border-bottom: 1px solid var(--c-net);
}

.page-about .chain-key {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--c-pulse);
}

.page-about .chain-val {
  font-size: 14.5px;
  line-height: 1.6;
  color: var(--c-grey);
}

/* 版本轨道 */
.page-about .version-rail {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
}

.page-about .version-step {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 14px;
  padding: 22px 0;
  border-top: 1px solid var(--c-net);
}

.page-about .version-step:last-child {
  border-bottom: 1px solid var(--c-net);
}

.page-about .version-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(28px, 4vw, 52px);
  font-weight: 700;
  line-height: 0.85;
  letter-spacing: -0.05em;
  color: var(--c-pulse);
  opacity: 0.85;
}

.page-about .version-body {
  min-width: 0;
}

.page-about .version-title {
  margin: 0;
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--c-ice);
}

.page-about .version-body p {
  max-width: 62ch;
  margin: 9px 0 0;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--c-ice);
}

/* 团队两栏 */
.page-about .node-content--split {
  display: grid;
  gap: 24px;
}

.page-about .node-main {
  min-width: 0;
}

.page-about .node-figure {
  margin: 24px 0 0;
}

/* 规模列表 */
.page-about .scale-list {
  margin: 26px 0 0;
  padding: 0;
  border-top: 1px solid var(--c-net);
}

.page-about .scale-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: baseline;
  gap: 16px;
  padding: 14px 0;
  border-bottom: 1px solid var(--c-net);
}

.page-about .scale-item dt {
  font-size: 15px;
  line-height: 1.6;
  color: var(--c-ice);
}

.page-about .scale-item dd {
  margin: 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(20px, 2.6vw, 32px);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1;
  color: var(--c-pulse);
}

/* ============ 收束区 ============ */
.page-about .about-cta {
  padding: var(--about-pad) 0;
  border-top: 1px solid var(--c-net);
  background: linear-gradient(135deg, var(--c-stand) 0%, var(--c-field) 65%);
}

.page-about .cta-inner {
  display: grid;
  gap: 26px;
}

.page-about .cta-title {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-size: clamp(25px, 3.6vw, 46px);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.022em;
  color: var(--c-ice);
}

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

/* ============ 媒体查询 ============ */
@media (min-width: 680px) {
  .page-about .chain-item {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: 24px;
    align-items: baseline;
  }
}

@media (min-width: 760px) {
  .page-about .version-step {
    grid-template-columns: 96px minmax(0, 1fr);
    gap: 28px;
    padding: 28px 0;
  }
}

@media (min-width: 860px) {
  .page-about .cta-inner {
    grid-template-columns: minmax(0, 1.5fr) auto;
    align-items: end;
    gap: 48px;
  }
}

@media (min-width: 900px) {
  .page-about {
    --about-rail-col: 104px;
  }

  .page-about .about-track::before {
    content: "";
    position: absolute;
    left: 52px;
    top: 0;
    bottom: 0;
    width: 1px;
    background: var(--c-net);
  }

  .page-about .track-node {
    gap: 40px;
    padding: 46px 0 54px;
  }

  .page-about .track-node:first-child {
    padding-top: 52px;
  }

  .page-about .node-num::before {
    content: "";
    position: absolute;
    left: 48px;
    top: 8px;
    width: 8px;
    height: 8px;
    background: var(--c-pulse);
    box-shadow: 0 0 0 4px var(--c-pulse-08);
  }
}

@media (min-width: 1000px) {
  .page-about .node-content--split {
    grid-template-columns: minmax(0, 1fr) 300px;
    gap: 44px;
    align-items: start;
  }

  .page-about .node-figure {
    margin: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .btn-pulse,
  .page-about .btn-ghost,
  .page-about .inline-link {
    transition: none;
  }
}