.page-about {
  --about-rail: 216px;
  display: block;
  overflow-x: clip;
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px 12px;
  padding: 18px 0 0;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  color: var(--muted);
}
.page-about .about-crumb a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.page-about .about-crumb a:hover,
.page-about .about-crumb a:focus-visible {
  color: var(--orange);
  border-bottom-color: var(--orange);
}
.page-about .about-crumb span[aria-hidden] {
  color: var(--stroke);
}
.page-about .about-crumb span:last-child {
  color: var(--text);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: clamp(24px, 4.5vw, 56px) 0 clamp(30px, 5vw, 68px);
  border-bottom: 2px solid var(--stroke);
  background-image:
    linear-gradient(180deg, rgba(47, 224, 208, 0.07), transparent 60%),
    linear-gradient(90deg, rgba(255, 122, 47, 0.05), transparent 42%);
}
.page-about .about-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 52px);
  align-items: center;
}
.page-about .about-hero-copy {
  min-width: 0;
}
.page-about .eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.16em;
  color: var(--orange);
}
.page-about .eyebrow::before {
  content: "";
  width: 26px;
  height: 2px;
  background: var(--orange);
}
.page-about h1 {
  margin: 0 0 18px;
  font-size: clamp(29px, 5.1vw, 52px);
  font-weight: 900;
  line-height: 1.18;
  letter-spacing: -0.022em;
  color: var(--text);
}
.page-about h1 em {
  font-style: normal;
  color: var(--cyan);
}
.page-about .lead {
  margin: 0 0 24px;
  max-width: 620px;
  font-size: var(--fs-16);
  line-height: 1.85;
  color: var(--text);
}
.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}
.page-about .about-hero-visual {
  min-width: 0;
  border: 2px solid var(--stroke);
  background: var(--ink-3);
  box-shadow: var(--shadow-hard);
  overflow: hidden;
}
.page-about .about-hero-visual svg {
  display: block;
  width: 100%;
  height: auto;
}

/* ---------- 主体骨架 ---------- */
.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 3.5vw, 48px);
  padding: clamp(28px, 4.5vw, 60px) 0 clamp(44px, 6vw, 84px);
}
.page-about .about-body {
  min-width: 0;
}

/* ---------- 侧边目录 ---------- */
.page-about .about-toc {
  align-self: start;
  border: 2px solid var(--stroke);
  background: var(--ink-2);
  padding: 16px 14px 18px;
}
.page-about .toc-title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.18em;
  color: var(--orange);
}
.page-about .toc-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 2px;
}
.page-about .toc-list a {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 7px 8px;
  border-left: 3px solid transparent;
  font-size: var(--fs-14);
  color: var(--text);
  text-decoration: none;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease), color var(--dur) var(--ease);
}
.page-about .toc-list a span {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--muted);
  transition: color var(--dur) var(--ease);
}
.page-about .toc-list a:hover,
.page-about .toc-list a:focus-visible {
  border-left-color: var(--cyan);
  background: rgba(47, 224, 208, 0.09);
  color: var(--cyan);
}
.page-about .toc-list a:hover span,
.page-about .toc-list a:focus-visible span {
  color: var(--orange);
}

/* ---------- 数字统计带 ---------- */
.page-about .stat-band {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0 0 clamp(28px, 4vw, 46px);
  border: 2px solid var(--stroke);
  background: var(--stroke);
}
.page-about .stat-band--tight {
  margin: clamp(24px, 3.5vw, 40px) 0 0;
}
.page-about .stat-band--accent .stat-num {
  color: var(--orange);
}
.page-about .stat-cell {
  background: var(--ink-2);
  padding: 15px 15px 17px;
  min-width: 0;
}
.page-about .stat-num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(20px, 2.5vw, 29px);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.015em;
  color: var(--cyan);
}
.page-about .stat-label {
  display: block;
  margin-top: 7px;
  font-size: var(--fs-12);
  line-height: 1.6;
  letter-spacing: 0.04em;
  color: var(--muted);
}

/* ---------- 章节通用 ---------- */
.page-about .about-section {
  padding-top: clamp(26px, 4vw, 46px);
  border-top: 2px solid var(--stroke);
}
.page-about .about-section:first-of-type {
  border-top: 0;
  padding-top: 0;
}
.page-about .about-section + .about-section {
  margin-top: clamp(28px, 4vw, 50px);
}
.page-about .sec-kicker {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.16em;
  color: var(--cyan);
}
.page-about .sec-title {
  margin: 0 0 18px;
  max-width: 640px;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(21px, 2.9vw, 31px);
  line-height: 1.42;
  letter-spacing: 0.008em;
  color: var(--text);
}
.page-about .body-text {
  margin: 0 0 16px;
  max-width: 620px;
  font-size: var(--fs-16);
  line-height: 1.85;
  color: var(--text);
}
.page-about .about-section--narrow .sec-title,
.page-about .about-section--narrow .body-text {
  max-width: 580px;
}

/* ---------- 图片容器 ---------- */
.page-about .about-figure {
  margin: 0 0 clamp(20px, 3vw, 30px);
  border: 2px solid var(--stroke);
  background: var(--ink-3);
  box-shadow: var(--shadow-hard);
  overflow: hidden;
}
.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}
.page-about .about-figure figcaption {
  padding: 10px 14px;
  border-top: 2px solid var(--stroke);
  background: var(--ink-2);
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  line-height: 1.7;
  letter-spacing: 0.02em;
  color: var(--muted);
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  position: relative;
  margin: 24px 0 0;
  padding: 0 0 0 26px;
  list-style: none;
}
.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(180deg, var(--cyan), var(--orange));
  opacity: 0.6;
}
.page-about .about-timeline li {
  position: relative;
  padding-bottom: 26px;
}
.page-about .about-timeline li:last-child {
  padding-bottom: 0;
}
.page-about .about-timeline li::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 6px;
  width: 12px;
  height: 12px;
  border: 2px solid var(--cyan);
  background: var(--ink);
  box-shadow: 0 0 0 3px rgba(47, 224, 208, 0.15);
}
.page-about .about-timeline li:nth-child(even)::before {
  border-color: var(--orange);
  box-shadow: 0 0 0 3px rgba(255, 122, 47, 0.15);
}
.page-about .tl-label {
  display: block;
  margin-bottom: 5px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.12em;
  color: var(--orange);
}
.page-about .about-timeline h3 {
  margin: 0 0 7px;
  font-size: var(--fs-20);
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--text);
}
.page-about .about-timeline .body-text {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--muted);
}

/* ---------- 班次卡片 ---------- */
.page-about .shift-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: 6px;
}
.page-about .shift-card {
  border: 2px solid var(--stroke);
  background: var(--ink-2);
  padding: 16px 15px 18px;
  box-shadow: 4px 4px 0 0 var(--stroke);
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.page-about .shift-card:hover {
  transform: translate(-2px, -2px);
  border-color: rgba(47, 224, 208, 0.5);
  box-shadow: 7px 7px 0 0 var(--stroke);
}
.page-about .shift-time {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-20);
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--cyan);
}
.page-about .shift-name {
  margin: 6px 0 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  color: var(--orange);
}
.page-about .shift-card p:last-child {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 数据来源列表 ---------- */
.page-about .source-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  border: 2px solid var(--stroke);
  background: var(--stroke);
}
.page-about .source-list li {
  background: var(--ink-2);
  padding: 15px 16px 17px;
  border-left: 4px solid transparent;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}
.page-about .source-list li:hover {
  border-left-color: var(--cyan);
  background: #122a49;
}
.page-about .source-list strong {
  display: block;
  margin-bottom: 6px;
  font-size: var(--fs-16);
  font-weight: 700;
  color: var(--text);
}
.page-about .source-list span {
  display: block;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 研究板 ---------- */
.page-about .board-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}
.page-about .board-card {
  border: 2px solid var(--stroke);
  border-left: 6px solid var(--orange);
  background: var(--paper);
  color: var(--ink);
  padding: 18px 18px 20px;
  box-shadow: 5px 5px 0 0 var(--stroke);
}
.page-about .board-card h3 {
  margin: 0 0 9px;
  font-family: var(--font-serif);
  font-size: var(--fs-20);
  font-weight: 600;
  line-height: 1.4;
  color: var(--ink);
}
.page-about .board-card p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--ink-2);
}

/* ---------- 合作生态 ---------- */
.page-about .eco-list {
  margin: 6px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 16px;
}
.page-about .eco-list li {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 14px;
  padding: 4px 0 4px 14px;
  border-left: 3px solid var(--stroke);
  transition: border-color var(--dur) var(--ease);
}
.page-about .eco-list li:hover {
  border-left-color: var(--cyan);
}
.page-about .eco-num {
  font-family: var(--font-mono);
  font-size: var(--fs-20);
  font-weight: 700;
  color: var(--orange);
  line-height: 1.3;
}
.page-about .eco-list h3 {
  margin: 0 0 6px;
  font-size: var(--fs-16);
  font-weight: 700;
  color: var(--text);
}
.page-about .eco-list p {
  margin: 0;
  max-width: 620px;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 后续入口 ---------- */
.page-about .about-section--next {
  border-top: 2px solid var(--stroke);
}
.page-about .next-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  margin-top: 4px;
}
.page-about .next-card {
  display: block;
  border: 2px solid var(--stroke);
  background: var(--ink-2);
  padding: 16px 15px 18px;
  text-decoration: none;
  color: var(--text);
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.page-about .next-card:hover,
.page-about .next-card:focus-visible {
  border-color: var(--cyan);
  background: rgba(47, 224, 208, 0.08);
  transform: translateY(-2px);
}
.page-about .next-card strong {
  display: block;
  margin-bottom: 7px;
  font-size: var(--fs-16);
  font-weight: 700;
  color: var(--text);
}
.page-about .next-card span {
  display: block;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--muted);
}
.page-about .next-card em {
  display: block;
  margin-top: 12px;
  font-style: normal;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  color: var(--orange);
}

/* ---------- 响应式 ---------- */
@media (min-width: 600px) {
  .page-about .shift-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .next-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 720px) {
  .page-about .stat-band {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .source-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .board-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .shift-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 960px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 0.98fr);
  }
  .page-about .about-shell {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(30px, 4vw, 64px);
  }
  .page-about .about-toc {
    position: sticky;
    top: 92px;
  }
  .page-about .about-figure {
    max-width: 860px;
  }
}

@media (min-width: 1200px) {
  .page-about .about-figure {
    max-width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .shift-card,
  .page-about .next-card,
  .page-about .toc-list a,
  .page-about .source-list li,
  .page-about .eco-list li {
    transition: none;
  }
  .page-about .shift-card:hover,
  .page-about .next-card:hover {
    transform: none;
  }
}