.page-about {
  --about-gap: clamp(26px, 5vw, 54px);
  --about-toc-w: 214px;
  overflow-x: clip;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(24px, 5vw, 56px) 0 clamp(26px, 4.5vw, 46px);
}

.page-about .about-hero .breadcrumb {
  margin-bottom: clamp(18px, 3vw, 30px);
  font-size: 13px;
}

.page-about .about-hero .breadcrumb ol {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  color: var(--mist);
}

.page-about .about-hero .breadcrumb li + li::before {
  content: "/";
  margin-right: 8px;
  color: var(--line);
}

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

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

.page-about .about-hero .eyebrow {
  color: var(--cyan);
  letter-spacing: 0.18em;
  font-size: 12px;
}

.page-about .about-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(30px, 5.4vw, 60px);
  line-height: 1.06;
  letter-spacing: -0.02em;
  font-weight: 700;
  color: var(--text);
  margin: 12px 0 18px;
  max-width: 22ch;
}

.page-about .about-hero h1 .hl {
  color: var(--cyan);
  text-shadow: 0 0 26px rgba(53, 230, 255, 0.28);
}

.page-about .about-hero .lede {
  max-width: 62ch;
  margin: 0;
  color: var(--mist);
  font-size: clamp(15px, 2.2vw, 17px);
  line-height: 1.85;
}

.page-about .stat-strip {
  list-style: none;
  margin: clamp(24px, 4vw, 38px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(132px, 1fr));
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line);
}

.page-about .stat-strip li {
  background: var(--cabin);
  padding: 14px 16px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

.page-about .stat-num {
  font-family: var(--font-mono);
  font-size: clamp(20px, 3.2vw, 28px);
  line-height: 1.1;
  color: var(--cyan);
}

.page-about .stat-label {
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: var(--mist);
}

/* ---------- 外框与章节目录 ---------- */
.page-about .about-shell {
  padding-top: clamp(28px, 5vw, 56px);
}

.page-about .about-toc {
  margin-bottom: 26px;
  padding: 14px;
  border: 1px solid var(--line);
  background: rgba(14, 21, 38, 0.78);
  backdrop-filter: blur(8px);
  min-width: 0;
}

.page-about .about-toc .toc-title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--mist);
}

.page-about .about-toc .index-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2px;
}

.page-about .about-toc .index-item {
  min-width: 0;
}

.page-about .about-toc .index-item a {
  display: flex;
  align-items: center;
  gap: 8px;
  min-height: 44px;
  padding: 6px 8px;
  font-size: 13.5px;
  color: var(--mist);
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: color 0.18s var(--ease), background 0.18s var(--ease), border-color 0.18s var(--ease);
}

.page-about .about-toc .index-item a .mono {
  font-size: 11px;
  color: var(--line);
}

.page-about .about-toc .index-item a:hover,
.page-about .about-toc .index-item a:focus-visible {
  color: var(--text);
  background: rgba(53, 230, 255, 0.06);
}

.page-about .about-toc .index-item a[aria-current="true"] {
  color: var(--cyan);
  border-left-color: var(--cyan);
  background: rgba(53, 230, 255, 0.09);
}

.page-about .about-toc .index-item a[aria-current="true"] .mono {
  color: var(--cyan);
}

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

/* ---------- 通用章节 ---------- */
.page-about .about-section {
  margin-bottom: clamp(40px, 7vw, 76px);
  min-width: 0;
}

.page-about .about-section:last-child {
  margin-bottom: 0;
}

.page-about .chapter-mark {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 12px;
  font-size: 11.5px;
  letter-spacing: 0.2em;
  color: var(--cyan);
}

.page-about .chapter-mark::before {
  content: "";
  width: 18px;
  height: 2px;
  background: var(--violet);
}

.page-about .section-title {
  font-family: var(--font-display);
  font-size: clamp(23px, 3.5vw, 36px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  margin: 0 0 12px;
  color: var(--text);
}

.page-about .lede {
  margin: 0 0 20px;
  color: var(--mist);
  font-size: clamp(14.5px, 2vw, 16px);
  line-height: 1.82;
  max-width: 58ch;
}

.page-about .media-frame {
  border: 1px solid var(--line);
  overflow: hidden;
  background: var(--cabin);
  min-width: 0;
}

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

.page-about .about-section .media-caption {
  margin: 9px 0 0;
  font-size: 12.5px;
  line-height: 1.65;
  color: var(--mist);
}

/* ---------- 01 研究板 ---------- */
.page-about .board-panel {
  padding: clamp(20px, 4vw, 42px);
  background: var(--paper);
  color: var(--ink);
  border: 1px solid #d9ccb2;
  box-shadow: var(--shadow-panel);
}

.page-about .board-panel .section-title {
  color: var(--ink);
}

.page-about .board-panel p {
  margin: 0 0 14px;
  color: rgba(16, 19, 28, 0.82);
  font-size: 15px;
  line-height: 1.85;
}

.page-about .board-panel .chapter-mark {
  color: #4a34b8;
}

.page-about .board-grid {
  display: grid;
  gap: clamp(20px, 3.5vw, 32px);
}

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

.page-about .board-facts {
  list-style: none;
  margin: 24px 0 0;
  padding: 18px 0 0;
  border-top: 1px solid rgba(16, 19, 28, 0.16);
  display: grid;
  gap: 14px 20px;
}

.page-about .board-facts li {
  display: flex;
  flex-direction: column;
  gap: 3px;
  padding-left: 10px;
  border-left: 2px solid var(--violet);
  min-width: 0;
}

.page-about .fact-key {
  font-size: 10.5px;
  letter-spacing: 0.16em;
  color: rgba(16, 19, 28, 0.58);
}

.page-about .fact-val {
  font-size: 14.5px;
  line-height: 1.55;
  color: var(--ink);
  font-weight: 500;
}

.page-about .board-figure {
  margin: 0;
  min-width: 0;
}

.page-about .board-panel .media-caption {
  color: rgba(16, 19, 28, 0.6);
}

/* ---------- 02 里程碑 ---------- */
.page-about .milestone-section {
  position: relative;
  overflow: hidden;
  padding: clamp(22px, 4vw, 44px);
  border: 1px solid var(--line);
  background: linear-gradient(155deg, var(--cabin) 0%, rgba(14, 21, 38, 0.45) 55%, var(--void) 100%);
}

.page-about .milestone-section::after {
  content: "";
  position: absolute;
  top: -46px;
  right: -66px;
  width: 230px;
  height: 230px;
  background: linear-gradient(135deg, rgba(108, 76, 241, 0.3), transparent 70%);
  transform: rotate(18deg);
  pointer-events: none;
}

.page-about .milestone-section > * {
  position: relative;
  z-index: 1;
}

.page-about .milestone-track {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .year-item {
  position: relative;
  padding: 16px 0 16px 24px;
  border-left: 1px solid var(--line);
  transition: background 0.2s var(--ease);
}

.page-about .year-item::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 21px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--line);
  transition: background 0.2s var(--ease), box-shadow 0.2s var(--ease);
}

.page-about .year-item:hover {
  background: rgba(53, 230, 255, 0.05);
}

.page-about .year-item:hover::before {
  background: var(--cyan);
  box-shadow: 0 0 0 4px rgba(53, 230, 255, 0.16);
}

.page-about .year-code {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--lava);
}

.page-about .year-item h3 {
  font-family: var(--font-display);
  font-size: 16px;
  line-height: 1.3;
  margin: 5px 0 6px;
  color: var(--text);
}

.page-about .year-item p {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .milestone-figure {
  margin: 26px 0 0;
}

/* ---------- 03 团队 ---------- */
.page-about .team-grid {
  display: grid;
  gap: 12px;
  margin-top: 6px;
}

.page-about .role-card {
  border: 1px solid var(--line);
  background: var(--cabin);
  min-width: 0;
  transition: border-color 0.2s var(--ease), background 0.2s var(--ease);
}

.page-about .role-card[open] {
  border-color: rgba(53, 230, 255, 0.5);
  background: rgba(53, 230, 255, 0.04);
}

.page-about .role-card > summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  padding: 14px 16px;
}

.page-about .role-card > summary::-webkit-details-marker {
  display: none;
}

.page-about .role-card > summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--cyan);
}

.page-about .role-card[open] > summary::after {
  content: "–";
}

.page-about .role-index {
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--cyan);
  border: 1px solid var(--line);
  padding: 2px 6px;
}

.page-about .role-name {
  font-family: var(--font-display);
  font-size: 15.5px;
  color: var(--text);
}

.page-about .role-card p {
  margin: 0;
  padding: 0 16px 16px;
  font-size: 14px;
  line-height: 1.78;
  color: var(--mist);
}

.page-about .review-band {
  margin-top: 22px;
  padding: clamp(18px, 3vw, 30px);
  border-left: 3px solid var(--violet);
  background: rgba(108, 76, 241, 0.1);
}

.page-about .review-band h3 {
  font-family: var(--font-display);
  font-size: clamp(17px, 2.4vw, 21px);
  line-height: 1.3;
  margin: 0 0 8px;
  color: var(--text);
}

.page-about .review-band > p {
  margin: 0 0 16px;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .step-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .step-list li {
  border-top: 1px solid var(--line);
  padding-top: 10px;
  min-width: 0;
}

.page-about .step-key {
  display: block;
  font-size: 10.5px;
  letter-spacing: 0.18em;
  color: var(--lava);
  margin-bottom: 5px;
}

.page-about .step-list strong {
  display: block;
  font-size: 14.5px;
  color: var(--text);
  margin-bottom: 3px;
}

.page-about .step-desc {
  font-size: 13px;
  line-height: 1.65;
  color: var(--mist);
}

/* ---------- 04 合作生态 ---------- */
.page-about .partners-panel {
  padding: clamp(20px, 4vw, 38px);
  border: 1px solid var(--line);
  background: linear-gradient(200deg, rgba(108, 76, 241, 0.17), rgba(14, 21, 38, 0.92) 46%);
}

.page-about .partners-grid {
  display: grid;
  gap: 24px;
}

.page-about .node-list {
  list-style: none;
  margin: 0 0 20px;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .node-list li {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 14px;
  font-size: 13.5px;
  color: var(--text);
  border: 1px solid var(--line);
  background: var(--cabin);
  transition: border-color 0.2s var(--ease), color 0.2s var(--ease), background 0.2s var(--ease);
}

.page-about .node-list li .mono {
  font-size: 10.5px;
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .node-list li:hover {
  border-color: var(--cyan);
  color: var(--cyan);
  background: rgba(53, 230, 255, 0.07);
}

.page-about .partners-figure {
  margin: 0;
  min-width: 0;
}

/* ---------- 05 延伸阅读 ---------- */
.page-about .next-grid {
  display: grid;
  gap: 10px;
}

.page-about .next-card {
  display: block;
  padding: 18px;
  min-height: 44px;
  border: 1px solid var(--line);
  background: var(--cabin);
  color: var(--text);
  text-decoration: none;
  transition: transform 0.2s var(--ease), border-color 0.2s var(--ease), background 0.2s var(--ease);
}

.page-about .next-card:hover,
.page-about .next-card:focus-visible {
  border-color: var(--cyan);
  background: rgba(53, 230, 255, 0.06);
  transform: translateY(-2px);
}

.page-about .next-tag {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.2em;
  color: var(--lava);
}

.page-about .next-card h3 {
  font-family: var(--font-display);
  font-size: 17px;
  line-height: 1.3;
  margin: 7px 0 6px;
  color: var(--text);
}

.page-about .next-card p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.72;
  color: var(--mist);
}

.page-about .about-contact {
  margin: 22px 0 0;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  font-size: 13.5px;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .about-contact .mono {
  color: var(--text);
  word-break: break-all;
}

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

@media (min-width: 720px) {
  .page-about .step-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

@media (min-width: 820px) {
  .page-about .board-grid {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 0.9fr);
    align-items: start;
  }

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

@media (min-width: 900px) {
  .page-about .team-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1000px) {
  .page-about .milestone-track {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

  .page-about .year-item {
    border-left: 0;
    border-top: 1px solid var(--line);
    padding: 20px 12px 6px 0;
  }

  .page-about .year-item::before {
    left: 0;
    top: -5px;
  }

  .page-about .year-item h3 {
    font-size: 14.5px;
  }

  .page-about .year-item p {
    font-size: 13px;
    line-height: 1.65;
  }
}

@media (min-width: 1024px) {
  .page-about .about-shell {
    display: grid;
    grid-template-columns: var(--about-toc-w) minmax(0, 1fr);
    gap: var(--about-gap);
    align-items: start;
  }

  .page-about .about-toc {
    position: sticky;
    top: calc(var(--hud-h) + 18px);
    margin-bottom: 0;
  }

  .page-about .about-toc .index-list {
    grid-template-columns: minmax(0, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition-duration: 0.001ms !important;
    animation-duration: 0.001ms !important;
  }

  .page-about .next-card:hover,
  .page-about .next-card:focus-visible {
    transform: none;
  }
}