.page-about {
  --about-hairline: rgba(44, 81, 71, 0.85);
  --about-glow: rgba(56, 242, 208, 0.12);
  display: block;
  color: var(--text-primary);
  background:
    radial-gradient(120% 70% at 88% -8%, var(--about-glow), transparent 62%),
    var(--bg-deep);
  padding-bottom: clamp(24px, 4vw, 48px);
}

.page-about h2 {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(26px, 4vw, 40px);
  line-height: 1.14;
  letter-spacing: -0.01em;
  margin: 8px 0 14px;
}

.page-about h3 {
  font-family: var(--font-head);
  font-weight: 700;
  letter-spacing: 0.005em;
}

/* ---------- 顶部上下文 ---------- */
.page-about .about-topline {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--gap-sm);
  padding-top: clamp(18px, 3vw, 30px);
}

.page-about .about-stamp {
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--text-secondary);
  text-transform: uppercase;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: clamp(28px, 4vw, 44px);
  padding-block: clamp(22px, 4vw, 44px) clamp(36px, 6vw, 72px);
}

.page-about .hero-copy h1 {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(34px, 6.2vw, 62px);
  line-height: 1.05;
  letter-spacing: -0.015em;
  margin: 10px 0 18px;
}

.page-about .hero-copy h1 .hl {
  color: var(--accent-cyan);
  display: block;
}

.page-about .hero-lead {
  margin: 0 0 clamp(20px, 3vw, 28px);
  max-width: 36em;
  font-size: clamp(15px, 1.7vw, 17px);
  line-height: 1.78;
  color: var(--text-secondary);
}

.page-about .hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: clamp(22px, 3vw, 34px);
}

.page-about .hero-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line-green);
  border: 1px solid var(--line-green);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.page-about .fact {
  background: var(--surface-moss);
  padding: 15px 16px 13px;
}

.page-about .fact-value {
  display: block;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(24px, 3.4vw, 30px);
  line-height: 1;
  color: var(--text-primary);
}

.page-about .fact-value em {
  font-style: normal;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent-cyan);
  margin-left: 3px;
}

.page-about .fact-label {
  display: block;
  margin-top: 8px;
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--text-secondary);
}

.page-about .hero-visual {
  display: flex;
  flex-direction: column;
}

.page-about .hero-plate {
  margin: 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--line-green);
  box-shadow: 0 34px 70px -48px rgba(0, 0, 0, 0.95);
}

.page-about .hero-plate img,
.page-about .team-media img,
.page-about .archive-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------- 时间线卡片 ---------- */
.page-about .timeline-card {
  position: relative;
  margin: -30px 0 0 14px;
  padding: 20px clamp(16px, 3vw, 24px) 8px;
  background: var(--surface-moss);
  border: 1px solid var(--line-green);
  border-radius: var(--radius-lg);
  box-shadow: 0 24px 46px -38px rgba(0, 0, 0, 0.9);
}

.page-about .timeline-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding-bottom: 10px;
  margin-bottom: 12px;
  border-bottom: 1px solid var(--about-hairline);
}

.page-about .timeline-head .mono {
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--text-secondary);
}

.page-about .timeline {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 16px;
  bottom: 20px;
  width: 2px;
  background: linear-gradient(var(--accent-cyan), var(--line-green) 55%, var(--accent-amber));
  opacity: 0.6;
}

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

.page-about .tl-summary {
  display: grid;
  grid-template-columns: 12px auto minmax(0, 1fr);
  align-items: center;
  gap: 10px;
  padding: 9px 0;
  cursor: pointer;
  list-style: none;
  border-radius: 8px;
}

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

.page-about .tl-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--bg-deep);
  border: 2px solid var(--accent-cyan);
  box-shadow: 0 0 0 3px rgba(56, 242, 208, 0.12);
}

.page-about .tl-dot--amber {
  border-color: var(--accent-amber);
  box-shadow: 0 0 0 3px rgba(242, 184, 75, 0.14);
}

.page-about .tl-meta {
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--text-secondary);
  white-space: nowrap;
}

.page-about .tl-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-primary);
}

.page-about .tl-body {
  margin: 0 0 12px 22px;
  font-size: 13.5px;
  line-height: 1.72;
  color: var(--text-secondary);
}

.page-about .tl-summary:hover .tl-title {
  color: var(--accent-cyan);
}

.page-about .tl-summary:focus-visible {
  outline: 2px solid var(--focus-glow);
  outline-offset: 3px;
}

/* ---------- 版本双轨 ---------- */
.page-about .track-panel {
  margin-top: clamp(22px, 3.4vw, 36px);
  padding: clamp(16px, 3vw, 32px);
  background: var(--bg-carbon);
  border: 1px solid var(--line-green);
  border-radius: var(--radius-lg);
}

.page-about .track-figure {
  margin: 0 0 clamp(18px, 3vw, 26px);
  padding: clamp(12px, 2.4vw, 22px) clamp(10px, 2vw, 20px);
  background: rgba(7, 21, 18, 0.72);
  border-radius: var(--radius-md);
}

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

.page-about .track-svg .rail {
  stroke-width: 2;
  fill: none;
}

.page-about .track-svg .rail--entry {
  stroke: var(--accent-cyan);
  opacity: 0.72;
}

.page-about .track-svg .rail--kernel {
  stroke: var(--accent-amber);
  opacity: 0.62;
}

.page-about .track-svg .node {
  stroke-width: 2;
  fill: var(--bg-deep);
}

.page-about .track-svg .node--entry {
  stroke: var(--accent-cyan);
}

.page-about .track-svg .node--kernel {
  stroke: var(--accent-amber);
}

.page-about .track-svg .link-line {
  stroke: var(--line-green);
  stroke-width: 1.5;
}

.page-about .track-svg .rail-tag {
  font-family: var(--font-mono);
  font-size: 15px;
  fill: var(--text-primary);
}

.page-about .track-svg .rail-sub {
  font-family: var(--font-body);
  font-size: 11px;
  fill: var(--text-secondary);
}

.page-about .track-svg .node-label {
  font-family: var(--font-body);
  font-size: 11px;
  text-anchor: middle;
  fill: var(--text-secondary);
}

/* ---------- 筛选按钮 ---------- */
.page-about .filter-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: clamp(16px, 2.6vw, 22px);
}

.page-about .filter-btn {
  appearance: none;
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  padding: 9px 16px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--line-green);
  background: transparent;
  color: var(--text-secondary);
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

.page-about .filter-btn:hover {
  border-color: var(--accent-cyan-dim);
  color: var(--text-primary);
}

.page-about .filter-btn[aria-pressed="true"] {
  background: var(--accent-cyan);
  border-color: var(--accent-cyan);
  color: var(--ink-on-accent);
}

.page-about .filter-btn:focus-visible {
  outline: 2px solid var(--focus-glow);
  outline-offset: 3px;
}

/* ---------- 双轨卡片 ---------- */
.page-about .track-grid {
  display: grid;
  gap: 12px;
}

.page-about .track-card {
  padding: clamp(16px, 2.4vw, 22px);
  background: var(--surface-moss);
  border: 1px solid var(--line-green);
  border-radius: var(--radius-md);
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease),
    background var(--dur) var(--ease);
}

.page-about .track-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent-cyan-dim);
  background: var(--surface-raised);
}

.page-about .track-card h3 {
  font-size: 17px;
  margin: 10px 0 8px;
}

.page-about .track-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--text-secondary);
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  display: grid;
  gap: clamp(24px, 4vw, 44px);
}

.page-about .team-media {
  margin: 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--line-green);
}

.page-about .team-media .media-caption,
.page-about .archive-figure .media-caption {
  padding: 12px 14px 0;
  font-size: 12px;
  line-height: 1.6;
  color: var(--text-secondary);
}

.page-about .team-lead {
  max-width: 60ch;
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.78;
  color: var(--text-secondary);
}

.page-about .team-cards {
  display: grid;
  gap: 10px;
  margin-top: clamp(18px, 3vw, 26px);
}

.page-about .team-card {
  padding: 16px;
  background: var(--surface-moss);
  border-left: 2px solid var(--accent-cyan-dim);
  border-radius: var(--radius-sm);
}

.page-about .team-num {
  display: block;
  font-size: 22px;
  line-height: 1;
  color: var(--accent-cyan);
  letter-spacing: 0.06em;
}

.page-about .team-card h3 {
  font-size: 15px;
  margin: 8px 0 6px;
}

.page-about .team-card p {
  margin: 0;
  font-size: 13px;
  line-height: 1.65;
  color: var(--text-secondary);
}

/* ---------- 四条主线 ---------- */
.page-about .lines-grid {
  list-style: none;
  margin: clamp(22px, 3.6vw, 34px) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-green);
  border: 1px solid var(--line-green);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.page-about .line-card {
  display: flex;
  flex-direction: column;
  gap: 9px;
  padding: clamp(18px, 2.6vw, 24px);
  background: var(--bg-deep);
  transition: background var(--dur) var(--ease);
}

.page-about .line-card:hover {
  background: var(--surface-moss);
}

.page-about .line-idx {
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--accent-cyan);
}

.page-about .line-card h3 {
  margin: 0;
  font-size: 18px;
}

.page-about .line-card p {
  margin: 0;
  flex: 1;
  font-size: 14px;
  line-height: 1.72;
  color: var(--text-secondary);
}

.page-about .line-link {
  align-self: flex-start;
  font-size: 13px;
  color: var(--accent-cyan);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 1px;
}

.page-about .line-link:hover {
  border-bottom-color: currentColor;
}

.page-about .line-link:focus-visible {
  outline: 2px solid var(--focus-glow);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- 资料归档 ---------- */
.page-about .archive-layout {
  display: grid;
  gap: clamp(20px, 3vw, 32px);
  margin-top: clamp(20px, 3vw, 28px);
}

.page-about .archive-grid {
  display: grid;
  gap: 10px;
}

.page-about .archive-card {
  padding: 16px;
  background: var(--surface-moss);
  border: 1px solid var(--line-green);
  border-radius: var(--radius-md);
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .archive-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent-cyan-dim);
}

.page-about .archive-card h3 {
  font-size: 15px;
  margin: 10px 0 7px;
}

.page-about .archive-card p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.68;
  color: var(--text-secondary);
}

.page-about .archive-figure {
  margin: 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--line-green);
}

/* ---------- 服务地区 ---------- */
.page-about .region-panel {
  display: grid;
  gap: clamp(22px, 4vw, 40px);
  padding: clamp(20px, 4vw, 44px);
  border-radius: var(--radius-lg);
  border: 1px solid var(--line-green);
  background:
    radial-gradient(90% 120% at 100% 0%, rgba(242, 184, 75, 0.08), transparent 58%),
    linear-gradient(155deg, var(--surface-moss), var(--bg-carbon) 72%);
}

.page-about .region-lead {
  max-width: 58ch;
  margin: 0 0 12px;
  font-size: 15px;
  line-height: 1.78;
  color: var(--text-secondary);
}

.page-about .region-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: clamp(16px, 2.6vw, 22px);
}

.page-about .contact-list {
  margin: 0;
  display: grid;
  gap: 1px;
  background: var(--line-green);
  border: 1px solid var(--line-green);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.page-about .contact-row {
  background: var(--bg-deep);
  padding: 12px 16px 13px;
}

.page-about .contact-row dt {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--text-secondary);
  margin-bottom: 5px;
}

.page-about .contact-row dd {
  margin: 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--text-primary);
  overflow-wrap: anywhere;
}

/* ---------- 页尾条 ---------- */
.page-about .about-foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-top: clamp(28px, 4vw, 44px);
  padding-top: clamp(18px, 3vw, 26px);
  border-top: 1px solid var(--line-green);
}

.page-about .about-foot-note {
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--text-secondary);
}

.page-about .to-top {
  font-size: 13px;
  color: var(--accent-cyan);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

.page-about .to-top:hover {
  border-bottom-color: currentColor;
}

.page-about .to-top:focus-visible {
  outline: 2px solid var(--focus-glow);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 560px) {
  .page-about .hero-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 700px) {
  .page-about .lines-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

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

@media (min-width: 900px) {
  .page-about .team-grid {
    grid-template-columns: minmax(0, 0.86fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .archive-layout {
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 0.7fr);
    align-items: start;
  }

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

@media (min-width: 960px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.92fr);
    align-items: start;
    gap: clamp(36px, 5vw, 68px);
  }

  .page-about .timeline-card {
    margin: -40px 0 0 12px;
  }

  .page-about .region-panel {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    align-items: center;
  }
}

@media (min-width: 1120px) {
  .page-about .lines-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .track-card,
  .page-about .archive-card,
  .page-about .filter-btn,
  .page-about .line-card {
    transition: none;
  }

  .page-about .track-card:hover,
  .page-about .archive-card:hover {
    transform: none;
  }
}