.page-about {
  --about-line: 2px solid var(--line);
  background: var(--ink);
  padding-bottom: clamp(48px, 7vw, 96px);
}

.page-about .breadcrumbs {
  padding: 18px 0 6px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  border-bottom: var(--about-line);
  background:
    radial-gradient(120% 90% at 88% 6%, rgba(198, 242, 78, .12), transparent 58%),
    linear-gradient(180deg, var(--deep) 0%, var(--ink) 100%);
  padding: clamp(26px, 5vw, 56px) 0 clamp(30px, 6vw, 64px);
}

.page-about .about-hero-grid {
  display: grid;
  gap: clamp(22px, 3.4vw, 40px);
}

.page-about .eyebrow {
  margin: 0 0 12px;
  font: 700 12px/1 var(--font-mono);
  letter-spacing: .2em;
  color: var(--orange);
  text-transform: uppercase;
}

.page-about h1 {
  margin: 0 0 16px;
  font-family: var(--font-sans);
  font-weight: 900;
  font-size: clamp(30px, 5.4vw, 58px);
  line-height: 1.08;
  letter-spacing: -.02em;
  color: var(--cream);
}

.page-about .about-lede {
  margin: 0;
  max-width: 34em;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.8;
  color: var(--paper);
}

.page-about .about-cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(18px, 2.6vw, 28px);
}

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

.page-about .hero-stat {
  border: var(--about-line);
  background: rgba(16, 35, 28, .78);
  padding: 14px 16px 16px;
  box-shadow: var(--dark-shadow);
}

.page-about .hero-stat-num {
  margin: 0;
  font: 800 clamp(26px, 3.6vw, 38px)/1 var(--font-mono);
  letter-spacing: -.02em;
  color: var(--lime);
}

.page-about .hero-stat-label {
  margin: 8px 0 0;
  font: 12px/1.6 var(--font-mono);
  letter-spacing: .1em;
  color: var(--stone);
}

/* ---------- 长卷骨架 ---------- */
.page-about .about-layout {
  display: grid;
  gap: clamp(20px, 3vw, 44px);
  padding-top: clamp(28px, 4.5vw, 56px);
}

.page-about .chapter-index {
  border-top: var(--about-line);
  border-bottom: var(--about-line);
  padding: 10px 0;
}

.page-about .chapter-index-title {
  margin: 0 0 8px;
  font: 700 11px/1 var(--font-mono);
  letter-spacing: .2em;
  color: var(--stone);
}

.page-about .chapter-index-list {
  display: flex;
  gap: 16px;
  margin: 0;
  padding: 0 0 4px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .chapter-index-list a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  white-space: nowrap;
  padding: 4px 0;
  font-size: 14px;
  font-weight: 600;
  color: var(--stone);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color 160ms ease, border-color 160ms ease;
}

.page-about .chapter-index-list a .idx {
  color: var(--lime);
}

.page-about .chapter-index-list a:hover,
.page-about .chapter-index-list a:focus-visible {
  color: var(--cream);
  border-bottom-color: var(--lime);
}

.page-about .about-chapter {
  border-top: var(--about-line);
  padding-top: clamp(32px, 5vw, 56px);
  margin-bottom: clamp(32px, 5vw, 64px);
}

.page-about .about-chapter:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .chapter-head {
  display: grid;
  gap: 8px;
  margin-bottom: clamp(18px, 2.6vw, 30px);
}

.page-about .chapter-num {
  margin: 0;
  font: 700 12px/1 var(--font-mono);
  letter-spacing: .18em;
  color: var(--lime);
}

.page-about .chapter-title {
  margin: 0;
  font-size: clamp(22px, 3.2vw, 36px);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -.02em;
  color: var(--cream);
}

.page-about .chapter-note {
  margin: 0;
  font: 12px/1.7 var(--font-mono);
  letter-spacing: .06em;
  color: var(--stone);
}

.page-about .prose {
  max-width: 40em;
  color: var(--paper);
}

.page-about .prose p {
  margin: 0 0 14px;
  font-size: 16px;
  line-height: 1.85;
}

.page-about .prose strong {
  color: var(--lime);
  font-weight: 700;
}

.page-about .about-split {
  display: grid;
  gap: clamp(20px, 3vw, 36px);
}

.page-about .about-split-text {
  display: grid;
  gap: clamp(18px, 2.6vw, 28px);
}

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

/* ---------- 团队分工 ---------- */
.page-about .duty-grid {
  display: grid;
  gap: 14px;
}

.page-about .duty-card {
  border: var(--about-line);
  background: var(--deep-2);
  padding: 16px 16px 18px;
  box-shadow: var(--dark-shadow);
}

.page-about .duty-tag {
  margin: 0 0 10px;
  font: 700 11px/1 var(--font-mono);
  letter-spacing: .16em;
  color: var(--orange);
}

.page-about .duty-title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.35;
  color: var(--cream);
}

.page-about .duty-text {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--stone);
}

/* ---------- 历程时间线 ---------- */
.page-about .tl-layout {
  display: grid;
  gap: clamp(20px, 3vw, 36px);
  margin-top: clamp(18px, 2.6vw, 28px);
}

.page-about .timeline {
  position: relative;
  margin: 0;
  padding: 4px 0 4px 22px;
  list-style: none;
  display: grid;
  gap: 16px;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 10px;
  bottom: 10px;
  width: 2px;
  background: var(--moss);
}

.page-about .timeline-node {
  position: relative;
}

.page-about .timeline-node::before {
  content: "";
  position: absolute;
  left: -21px;
  top: 20px;
  width: 12px;
  height: 12px;
  background: var(--orange);
  border: 2px solid var(--ink);
}

.page-about .timeline-item {
  border: var(--about-line);
  background: var(--deep);
}

.page-about .tl-summary {
  display: grid;
  gap: 4px;
  padding: 12px 14px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .tl-era {
  font: 700 12px/1 var(--font-mono);
  letter-spacing: .16em;
  color: var(--stone);
}

.page-about .tl-head {
  font-size: 16px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--cream);
}

.page-about .tl-summary:hover .tl-head,
.page-about .tl-summary:focus-visible .tl-head {
  color: var(--lime);
}

.page-about .tl-item[open] > .tl-summary {
  border-bottom: var(--about-line);
}

.page-about .tl-item[open] .tl-era {
  color: var(--lime);
}

.page-about .tl-body {
  padding: 12px 14px 14px;
  background: var(--deep-2);
}

.page-about .tl-body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--paper);
}

/* ---------- 协作网络 ---------- */
.page-about .network-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 12px;
}

.page-about .network-item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: center;
  gap: 14px;
  border-left: 6px solid var(--clay);
  background: rgba(23, 52, 42, .6);
  padding: 12px 14px;
}

.page-about .network-num {
  font: 800 clamp(22px, 2.6vw, 30px)/1 var(--font-mono);
  color: var(--lime);
}

.page-about .network-label {
  font-size: 13px;
  line-height: 1.7;
  color: var(--stone);
}

/* ---------- 荣誉 ---------- */
.page-about .honor-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .honor-tag {
  flex: 1 1 240px;
  border: var(--about-line);
  background: var(--deep-2);
  padding: 16px;
  box-shadow: var(--dark-shadow);
}

.page-about .honor-kicker {
  display: block;
  margin-bottom: 10px;
  font: 700 11px/1 var(--font-mono);
  letter-spacing: .16em;
  color: var(--clay);
}

.page-about .honor-tag b {
  display: block;
  font-size: 15px;
  font-weight: 700;
  line-height: 1.6;
  color: var(--cream);
}

.page-about .honor-note {
  display: block;
  margin-top: 8px;
  font: 12px/1.6 var(--font-mono);
  color: var(--stone);
}

/* ---------- 选择理由与起步 ---------- */
.page-about .reason-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 18px;
}

.page-about .reason-item {
  border-top: 2px solid var(--lime);
  padding-top: 14px;
}

.page-about .reason-num {
  margin: 0 0 8px;
  font: 800 clamp(24px, 3vw, 34px)/1 var(--font-mono);
  color: var(--lime);
}

.page-about .reason-title {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 700;
  color: var(--cream);
}

.page-about .reason-text {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--paper);
}

.page-about .start-block {
  margin-top: clamp(26px, 4vw, 44px);
  border: var(--about-line);
  background: linear-gradient(180deg, var(--deep) 0%, var(--ink) 100%);
  padding: clamp(18px, 3vw, 30px);
  box-shadow: var(--dark-shadow);
}

.page-about .start-title {
  margin: 0 0 16px;
  font-size: clamp(18px, 2.2vw, 22px);
  font-weight: 800;
  letter-spacing: -.01em;
  color: var(--cream);
}

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

.page-about .start-links a {
  display: block;
  border: var(--about-line);
  padding: 13px 15px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--paper);
  text-decoration: none;
  transition: border-color 160ms ease, color 160ms ease, background 160ms ease;
}

.page-about .start-links a:hover,
.page-about .start-links a:focus-visible {
  border-color: var(--lime);
  background: var(--deep-2);
  color: var(--cream);
}

/* ---------- 响应式 ---------- */
@media (min-width: 760px) {
  .page-about .duty-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .honor-strip {
    gap: 14px;
  }

  .page-about .tl-layout {
    grid-template-columns: minmax(0, 1fr) minmax(200px, 300px);
    align-items: start;
  }

  .page-about .reason-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 24px 28px;
  }

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

@media (min-width: 900px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: end;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1fr) minmax(280px, 400px);
    align-items: start;
  }

  .page-about .about-split--reverse {
    grid-template-columns: minmax(280px, 420px) minmax(0, 1fr);
  }

  .page-about .about-split--reverse .about-figure {
    order: -1;
  }
}

@media (min-width: 980px) {
  .page-about .about-layout {
    grid-template-columns: 190px minmax(0, 1fr);
    align-items: start;
  }

  .page-about .chapter-index {
    position: sticky;
    top: 104px;
    border-top: 0;
    border-bottom: 0;
    border-left: var(--about-line);
    padding: 4px 0 4px 16px;
  }

  .page-about .chapter-index-list {
    flex-direction: column;
    gap: 14px;
    overflow: visible;
  }

  .page-about .chapter-index-list a {
    border-bottom: 0;
    border-left: 2px solid transparent;
    padding: 2px 0 2px 8px;
    margin-left: -10px;
  }

  .page-about .chapter-index-list a:hover,
  .page-about .chapter-index-list a:focus-visible {
    border-left-color: var(--lime);
  }

  .page-about .chapter-title {
    max-width: 22em;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .chapter-index-list a,
  .page-about .start-links a {
    transition: none;
  }
}