.page-about {
  background: var(--ink-900);
  color: var(--paper-100);
  padding-bottom: 0;
}

.page-about .breadcrumb {
  padding: 22px 0 6px;
  font-size: var(--step-12);
  letter-spacing: .12em;
  color: var(--steel-400);
}

.page-about .breadcrumb a {
  color: var(--steel-400);
  text-decoration: none;
}

.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--cyan-400);
}

/* ---------- 开篇 ---------- */
.page-about .about-intro {
  padding: 26px 0 56px;
}

.page-about .about-intro-grid {
  display: grid;
  gap: 30px;
}

.page-about h1 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(32px, 8.4vw, var(--step-62));
  line-height: 1.06;
  letter-spacing: -.02em;
  margin: 10px 0 20px;
  text-wrap: balance;
}

.page-about .eyebrow {
  font-size: var(--step-12);
  letter-spacing: .2em;
  color: var(--cyan-400);
  text-transform: uppercase;
  margin: 0;
}

.page-about .about-lead {
  font-size: var(--step-17);
  line-height: 1.78;
  color: var(--paper-100);
  margin: 0 0 16px;
  max-width: 62ch;
}

.page-about .about-intro-copy p:not(.eyebrow):not(.about-lead) {
  font-size: var(--step-17);
  line-height: 1.78;
  color: var(--steel-400);
  margin: 0 0 16px;
  max-width: 62ch;
}

.page-about .about-facts {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line-600);
  border: var(--edge);
  box-shadow: var(--shadow-hard-sm);
}

.page-about .about-facts li {
  background: var(--ink-800);
  padding: 16px 14px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .about-facts .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--step-30);
  line-height: 1;
  color: var(--cyan-400);
}

.page-about .about-facts .fact-label {
  font-size: var(--step-12);
  letter-spacing: .06em;
  color: var(--steel-400);
  line-height: 1.5;
}

.page-about .about-intro-media {
  margin: 0;
  border: var(--edge);
  box-shadow: var(--shadow-hard);
  background: var(--ink-800);
}

.page-about .about-intro-media .media-frame {
  margin: 0;
}

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

.page-about .media-frame__caption {
  display: block;
  padding: 12px 14px;
  font-size: var(--step-12);
  letter-spacing: .08em;
  color: var(--steel-400);
  border-top: 1px solid var(--line-600);
}

/* ---------- 章节头 ---------- */
.page-about .about-sec-head {
  margin-bottom: 26px;
}

.page-about .section-index {
  font-family: var(--font-mono);
  font-size: var(--step-12);
  letter-spacing: .18em;
  color: var(--cyan-400);
  margin: 0 0 10px;
}

.page-about h2 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(26px, 6vw, var(--step-44));
  line-height: 1.1;
  letter-spacing: -.015em;
  margin: 0 0 12px;
  text-wrap: balance;
}

.page-about .about-sec-lead {
  font-size: var(--step-17);
  line-height: 1.78;
  color: var(--steel-400);
  margin: 0;
  max-width: 66ch;
}

/* ---------- 时间轴 ---------- */
.page-about .about-timeline {
  padding: 34px 0 58px;
  border-top: 2px solid var(--line-600);
}

.page-about .tl-rail {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 20px;
}

.page-about .tl-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 14px;
  font-size: var(--step-14);
  color: var(--paper-100);
  text-decoration: none;
  background: var(--ink-800);
  border: var(--edge);
  transition: transform .18s var(--ease), border-color .18s var(--ease), background .18s var(--ease);
}

.page-about .tl-chip .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  color: var(--cyan-400);
}

.page-about .tl-chip:hover,
.page-about .tl-chip:focus-visible {
  border-color: var(--cyan-400);
  background: var(--panel-700);
  transform: translate(-2px, -2px);
  outline: none;
}

.page-about .tl-chip--hot {
  border-color: var(--orange-500);
}

.page-about .tl-chip--hot .num {
  color: var(--orange-500);
}

.page-about .tl-track {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: 82%;
  gap: 14px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  padding: 2px 2px 18px;
  scrollbar-color: var(--cyan-500) var(--ink-800);
}

.page-about .tl-card {
  scroll-snap-align: start;
  background: var(--ink-800);
  border: var(--edge);
  padding: 20px 18px 18px;
  box-shadow: var(--shadow-hard-sm);
  position: relative;
}

.page-about .tl-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 6px;
  background: linear-gradient(90deg, var(--cyan-500), var(--cyan-400));
}

.page-about .tl-card--hot::before {
  background: linear-gradient(90deg, var(--orange-500), var(--cyan-400));
}

.page-about .tl-ver {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--step-44);
  line-height: 1;
  color: var(--cyan-400);
  margin: 8px 0 12px;
  letter-spacing: -.02em;
}

.page-about .tl-card--hot .tl-ver {
  color: var(--orange-500);
}

.page-about .tl-card h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--step-22);
  line-height: 1.25;
  margin: 0 0 10px;
}

.page-about .tl-card p {
  font-size: var(--step-14);
  line-height: 1.8;
  color: var(--steel-400);
  margin: 0 0 12px;
}

.page-about .tl-card .tl-solve {
  margin: 0;
  padding-top: 10px;
  border-top: 1px solid var(--line-600);
  color: var(--cyan-200);
  font-size: var(--step-12);
  letter-spacing: .04em;
}

.page-about .about-tl-media {
  margin: 18px 0 0;
  border: var(--edge);
  background: var(--ink-800);
  box-shadow: var(--shadow-hard);
}

/* ---------- 数据流程 ---------- */
.page-about .about-data {
  padding: 34px 0 58px;
  border-top: 2px solid var(--line-600);
  background: linear-gradient(180deg, var(--ink-900), var(--ink-800) 60%, var(--ink-900));
}

.page-about .flow {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 16px;
  counter-reset: flowstep;
}

.page-about .flow-step {
  position: relative;
  background: var(--panel-700);
  border: var(--edge);
  padding: 20px 18px;
  box-shadow: var(--shadow-hard-sm);
}

.page-about .flow-step::after {
  content: "";
  position: absolute;
  left: 18px;
  right: 18px;
  top: 0;
  height: 6px;
  background: linear-gradient(90deg, var(--cyan-400), rgba(56, 225, 255, 0));
}

.page-about .flow-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--step-12);
  letter-spacing: .18em;
  color: var(--orange-500);
  margin: 6px 0 8px;
}

.page-about .flow-step h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--step-22);
  margin: 0 0 8px;
}

.page-about .flow-step p {
  font-size: var(--step-14);
  line-height: 1.8;
  color: var(--steel-400);
  margin: 0;
}

.page-about .data-partners {
  margin-top: 22px;
  padding: 20px 18px;
  border-left: 6px solid var(--cyan-400);
  background: var(--ink-800);
}

.page-about .data-partners-title {
  font-size: var(--step-12);
  letter-spacing: .2em;
  color: var(--cyan-400);
  margin: 0 0 8px;
}

.page-about .data-partners p:last-child {
  font-size: var(--step-17);
  line-height: 1.8;
  color: var(--paper-100);
  margin: 0;
  max-width: 68ch;
}

/* ---------- 团队 ---------- */
.page-about .about-team {
  padding: 34px 0 58px;
  border-top: 2px solid var(--line-600);
}

.page-about .team-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.page-about .team-cell {
  background: var(--ink-800);
  border: var(--edge);
  padding: 16px 14px;
  box-shadow: var(--shadow-hard-sm);
  transition: border-color .2s var(--ease), background .2s var(--ease);
}

.page-about .team-cell:hover,
.page-about .team-cell:focus-visible {
  border-color: var(--cyan-400);
  background: var(--panel-700);
  outline: none;
}

.page-about .team-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--step-30);
  line-height: 1;
  color: var(--cyan-400);
  margin: 0 0 8px;
}

.page-about .team-cell h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--step-17);
  letter-spacing: .02em;
  margin: 0 0 8px;
}

.page-about .team-desc {
  font-size: var(--step-12);
  line-height: 1.75;
  color: var(--steel-400);
  margin: 0;
}

.page-about .team-foot {
  margin: 18px 0 0;
  font-size: var(--step-14);
  color: var(--steel-400);
  letter-spacing: .04em;
}

/* ---------- 资质 ---------- */
.page-about .about-cert {
  padding: 34px 0 58px;
  border-top: 2px solid var(--line-600);
  background: var(--ink-800);
}

.page-about .about-cert-grid {
  align-items: start;
}

.page-about .cert-list {
  display: grid;
  gap: 10px;
  margin: 20px 0 22px;
}

.page-about .cert-item {
  border: var(--edge);
  background: var(--ink-900);
}

.page-about .cert-item summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 16px;
  font-size: var(--step-14);
  font-weight: 500;
  color: var(--paper-100);
}

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

.page-about .cert-item summary:focus-visible {
  outline: 2px solid var(--cyan-400);
  outline-offset: -2px;
}

.page-about .cert-mark {
  width: 12px;
  height: 12px;
  flex: 0 0 auto;
  border: 1.5px solid var(--cyan-400);
  background: transparent;
  transition: background .2s var(--ease);
}

.page-about .cert-item[open] .cert-mark {
  background: var(--cyan-400);
}

.page-about .cert-item p {
  margin: 0;
  padding: 0 16px 16px;
  font-size: var(--step-14);
  line-height: 1.8;
  color: var(--steel-400);
}

.page-about .eco-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .eco-list li {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 12px 14px;
  background: var(--panel-700);
  border-left: 4px solid var(--orange-500);
  font-size: var(--step-14);
  line-height: 1.7;
  color: var(--paper-100);
}

.page-about .eco-key {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--step-22);
  line-height: 1;
  color: var(--cyan-400);
  flex: 0 0 auto;
}

.page-about .cert-media {
  margin: 26px 0 0;
  border: var(--edge);
  background: var(--ink-900);
  box-shadow: var(--shadow-hard);
}

/* ---------- 场景 ---------- */
.page-about .about-scene {
  padding: 34px 0 58px;
  border-top: 2px solid var(--line-600);
}

.page-about .scene-grid {
  display: grid;
  gap: 14px;
}

.page-about .scene-card {
  background: var(--ink-800);
  border: var(--edge);
  padding: 20px 18px;
  box-shadow: var(--shadow-hard-sm);
}

.page-about .scene-card h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--step-22);
  line-height: 1.24;
  margin: 0 0 10px;
}

.page-about .scene-card p:not(.eyebrow) {
  font-size: var(--step-14);
  line-height: 1.8;
  color: var(--steel-400);
  margin: 0 0 14px;
}

.page-about .scene-card .link {
  font-size: var(--step-14);
  color: var(--cyan-400);
  text-decoration: none;
  border-bottom: 1px solid var(--line-600);
  padding-bottom: 2px;
}

.page-about .scene-card .link:hover,
.page-about .scene-card .link:focus-visible {
  color: var(--orange-500);
  border-bottom-color: var(--orange-500);
  outline: none;
}

.page-about .scene-card--wide {
  background: linear-gradient(135deg, var(--panel-700), var(--ink-800) 65%);
  border-color: var(--cyan-500);
}

/* ---------- 收尾 ---------- */
.page-about .chapter-band {
  height: 6px;
  background: linear-gradient(90deg, var(--cyan-400), var(--orange-500) 70%, var(--ink-900));
}

.page-about .about-next {
  padding: 40px 0 56px;
  background: var(--ink-800);
}

.page-about .about-next-inner {
  display: grid;
  gap: 22px;
}

.page-about .about-next h2 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(24px, 5.6vw, var(--step-30));
  margin: 0 0 8px;
}

.page-about .about-next p {
  margin: 0;
  font-size: var(--step-14);
  color: var(--steel-400);
}

.page-about .next-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 700px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .flow {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

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

  .page-about .scene-card--wide {
    grid-column: 1 / -1;
  }

  .page-about .about-next-inner {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
  }

  .page-about .tl-track {
    grid-auto-columns: 46%;
  }
}

@media (min-width: 1000px) {
  .page-about .about-intro {
    padding: 34px 0 70px;
  }

  .page-about .about-intro-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .about-timeline,
  .page-about .about-data,
  .page-about .about-team,
  .page-about .about-cert,
  .page-about .about-scene {
    padding: 52px 0 76px;
  }

  .page-about .tl-track {
    grid-auto-flow: row;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    overflow: visible;
    gap: 16px;
  }

  .page-about .about-cert-grid {
    gap: 32px;
  }

  .page-about .cert-media {
    margin-top: 0;
  }

  .page-about .scene-grid {
    grid-template-columns: 5fr 4fr 3fr;
    align-items: start;
  }

  .page-about .scene-card--wide {
    grid-column: auto;
  }
}

@media (hover: hover) and (pointer: fine) {
  .page-about .team-cell .team-desc {
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height .3s var(--ease), opacity .25s var(--ease), margin .3s var(--ease);
  }

  .page-about .team-cell:hover .team-desc,
  .page-about .team-cell:focus-visible .team-desc,
  .page-about .team-cell:focus-within .team-desc {
    max-height: 220px;
    opacity: 1;
    margin-top: 4px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tl-chip,
  .page-about .team-cell,
  .page-about .team-cell .team-desc,
  .page-about .cert-mark {
    transition: none;
  }

  .page-about .tl-chip:hover,
  .page-about .tl-chip:focus-visible {
    transform: none;
  }
}