.page-about {
  --about-rail-width: 300px;
  display: block;
  background: var(--ink);
  color: var(--text);
  font-family: var(--font-body);
  overflow-x: hidden;
}

.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
  width: 100%;
  max-width: 1440px;
  margin: 0 auto;
  padding: 20px 20px 88px;
  box-sizing: border-box;
}

/* ---------- 左侧章节索引 ---------- */
.page-about .about-rail {
  min-width: 0;
  border-top: 1px solid var(--line);
  padding-top: 14px;
}

.page-about .rail-nav {
  display: flex;
  gap: 18px;
  overflow-x: auto;
  padding-bottom: 10px;
  -webkit-overflow-scrolling: touch;
}

.page-about .rail-link {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  white-space: nowrap;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: rgba(233, 226, 214, 0.62);
  text-decoration: none;
  padding: 4px 0;
  border-bottom: 1px solid transparent;
  transition: color 0.25s var(--ease-out), border-color 0.25s var(--ease-out);
}

.page-about .rail-link:hover,
.page-about .rail-link:focus-visible {
  color: var(--blue-glow);
  border-bottom-color: var(--gold);
}

.page-about .rail-num {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--gold);
}

.page-about .rail-edition {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 6px 0 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--jade);
}

.page-about .status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--jade);
  animation: about-pulse 3.2s ease-in-out infinite;
}

@keyframes about-pulse {
  0%, 100% { opacity: 0.5; }
  50% { opacity: 0.95; }
}

/* ---------- 首屏 ---------- */
.page-about .about-flow {
  min-width: 0;
}

.page-about .breadcrumbs {
  margin-bottom: 26px;
}

.page-about .about-hero {
  display: grid;
  gap: 28px;
}

.page-about .hero-title {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(2.05rem, 5.6vw, 3.9rem);
  line-height: 1.06;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .hero-lead {
  margin: 20px 0 0;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.9;
  color: rgba(233, 226, 214, 0.82);
}

.page-about .hero-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 32px 0 0;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .hero-fact {
  background: var(--ink);
  padding: 14px 14px 16px;
}

.page-about .hero-fact dt {
  font-size: 11px;
  letter-spacing: 0.18em;
  color: rgba(233, 226, 214, 0.55);
}

.page-about .hero-fact dd {
  margin: 8px 0 0;
  font-family: var(--font-mono);
  font-size: 18px;
  letter-spacing: 0.02em;
  color: var(--gold);
}

/* ---------- 图片 ---------- */
.page-about .media {
  margin: 0;
}

.page-about .media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line);
}

.page-about .media--wide img {
  aspect-ratio: 3 / 2;
}

.page-about .media--tall img {
  aspect-ratio: 5 / 7;
}

.page-about .media-caption {
  margin-top: 10px;
  padding-left: 10px;
  border-left: 2px solid var(--gold);
  font-size: 12px;
  line-height: 1.7;
  letter-spacing: 0.05em;
  color: rgba(233, 226, 214, 0.55);
}

/* ---------- 章节骨架 ---------- */
.page-about .about-section {
  margin-top: 84px;
  scroll-margin-top: 110px;
}

.page-about .sec-head {
  position: relative;
  padding-left: 18px;
  margin-bottom: 26px;
}

.page-about .sec-head::before {
  content: "";
  position: absolute;
  left: 0;
  top: 4px;
  bottom: 4px;
  width: 1px;
  background: linear-gradient(180deg, var(--gold), rgba(232, 184, 92, 0));
}

.page-about .section-heading {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(1.32rem, 2.4vw, 1.9rem);
  line-height: 1.25;
  letter-spacing: -0.03em;
  color: var(--paper);
}

.page-about .body-copy {
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.9;
  color: rgba(233, 226, 214, 0.82);
  margin: 0;
}

.page-about .body-copy + .body-copy {
  margin-top: 18px;
}

.page-about .about-section .body-copy + .placard-grid,
.page-about .about-section .body-copy + .timeline-wrap,
.page-about .about-section .body-copy + .partner-list,
.page-about .about-section .body-copy + .team-media {
  margin-top: 30px;
}

/* ---------- 登记主线说明牌 ---------- */
.page-about .placard-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .placard {
  display: flex;
  flex-direction: column;
  gap: 12px;
  background: var(--paper);
  color: var(--ink);
  padding: 26px 22px 28px;
  transition: background 0.3s var(--ease-out);
}

.page-about .placard:hover {
  background: var(--paper-2);
}

.page-about .placard-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
}

.page-about .placard-title {
  margin: 0;
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.page-about .placard-index {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: rgba(18, 16, 15, 0.5);
}

.page-about .placard-text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: rgba(18, 16, 15, 0.75);
}

.page-about .placard-meta {
  margin: auto 0 0;
  padding-top: 12px;
  border-top: 1px solid rgba(18, 16, 15, 0.16);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--orange);
}

.page-about .tier-scale {
  display: flex;
  align-items: flex-end;
  gap: 4px;
  height: 34px;
  margin: 2px 0;
}

.page-about .tier-scale span {
  flex: 1 1 0;
  background: var(--teal-deep);
  border-top: 2px solid var(--gold);
}

.page-about .tier-scale span:nth-child(1) { height: 24%; }
.page-about .tier-scale span:nth-child(2) { height: 36%; }
.page-about .tier-scale span:nth-child(3) { height: 50%; }
.page-about .tier-scale span:nth-child(4) { height: 66%; }
.page-about .tier-scale span:nth-child(5) { height: 82%; }
.page-about .tier-scale span:nth-child(6) { height: 100%; }

/* ---------- 款次沿革 ---------- */
.page-about .timeline-wrap {
  display: grid;
  gap: 34px;
}

.page-about .timeline {
  display: grid;
  gap: 20px;
  margin-left: 6px;
  padding-left: 26px;
  border-left: 1px solid var(--line);
}

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

.page-about .tl-node::before {
  content: "";
  position: absolute;
  top: 14px;
  left: -31px;
  width: 9px;
  height: 9px;
  background: var(--gold);
  border: 1px solid var(--ink);
}

.page-about .tl-node summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 14px;
  cursor: pointer;
  list-style: none;
  padding: 6px 0;
}

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

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

.page-about .tl-year {
  font-family: var(--font-mono);
  font-size: 1rem;
  letter-spacing: 0.08em;
  color: var(--gold);
}

.page-about .tl-title {
  font-size: 1.05rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .tl-mark {
  position: relative;
  width: 12px;
  height: 12px;
  margin-left: auto;
  flex: 0 0 auto;
  align-self: center;
}

.page-about .tl-mark::before,
.page-about .tl-mark::after {
  content: "";
  position: absolute;
  background: var(--blue);
}

.page-about .tl-mark::before {
  left: 0;
  top: 5px;
  width: 12px;
  height: 1px;
}

.page-about .tl-mark::after {
  left: 5px;
  top: 0;
  width: 1px;
  height: 12px;
  transition: opacity 0.25s var(--ease-out);
}

.page-about .tl-node[open] .tl-mark::after {
  opacity: 0;
}

.page-about .tl-body {
  max-width: 60ch;
  margin: 10px 0 0;
  font-size: 15px;
  line-height: 1.85;
  color: rgba(233, 226, 214, 0.78);
}

.page-about .tl-node--current {
  background: var(--teal-deep);
  border: 1px solid var(--line);
  padding: 14px 18px 18px;
}

.page-about .tl-node--current::before {
  left: -33px;
  background: var(--blue-glow);
}

.page-about .tl-media img {
  border-color: var(--line);
}

/* ---------- 团队 ---------- */
.page-about .team-media {
  display: block;
}

.page-about .team-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  margin-top: 30px;
}

.page-about .team-cell {
  display: flex;
  flex-direction: column;
  gap: 10px;
  background: var(--panel);
  padding: 24px 22px 26px;
  transition: background 0.3s var(--ease-out);
}

.page-about .team-cell:hover,
.page-about .team-cell:focus-within {
  background: var(--teal-deep);
}

.page-about .team-cell:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: -2px;
}

.page-about .team-count {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 1.5rem;
  letter-spacing: 0.02em;
  color: var(--gold);
}

.page-about .team-count small {
  margin-left: 6px;
  font-family: var(--font-body);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: rgba(233, 226, 214, 0.6);
}

.page-about .team-name {
  margin: 0;
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .team-duty {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: rgba(233, 226, 214, 0.78);
}

.page-about .team-collab {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: auto 0 0;
  padding-top: 12px;
  border-top: 1px solid rgba(201, 192, 178, 0.22);
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: rgba(233, 226, 214, 0.6);
}

.page-about .team-collab .dot {
  flex: 0 0 auto;
  width: 6px;
  height: 6px;
  background: var(--jade);
}

/* ---------- 条目质量 ---------- */
.page-about .quality-wrap {
  display: grid;
  gap: 30px;
}

.page-about .check-list {
  list-style: none;
  display: grid;
  gap: 14px;
  margin: 22px 0 0;
  padding: 0;
}

.page-about .check-list li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 12px;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(233, 226, 214, 0.8);
}

.page-about .check-list b {
  font-family: var(--font-mono);
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--gold);
  white-space: nowrap;
}

.page-about .code-panel {
  background: var(--teal-deep);
  border: 1px solid var(--line);
  padding: 24px 20px 26px;
}

.page-about .code-display {
  display: flex;
  gap: 6px;
  margin: 14px 0 20px;
  font-family: var(--font-mono);
  font-size: clamp(1.6rem, 5vw, 2.2rem);
  letter-spacing: 0.12em;
  tabular-nums: 1;
}

.page-about .code-seg--cat { color: var(--blue); }
.page-about .code-seg--ver { color: var(--gold); }
.page-about .code-seg--seq { color: var(--jade); }

.page-about .code-legend {
  display: grid;
  gap: 14px;
  margin: 0;
}

.page-about .code-legend > div {
  padding-top: 12px;
  border-top: 1px solid rgba(201, 192, 178, 0.24);
}

.page-about .code-legend dt {
  font-size: 11px;
  letter-spacing: 0.18em;
  color: rgba(233, 226, 214, 0.55);
}

.page-about .code-legend dd {
  margin: 6px 0 0;
  font-size: 13.5px;
  line-height: 1.7;
  color: rgba(233, 226, 214, 0.78);
}

.page-about .code-note {
  margin: 18px 0 0;
  font-size: 13px;
  line-height: 1.75;
  color: rgba(233, 226, 214, 0.62);
}

/* ---------- 合作伙伴 ---------- */
.page-about .partner-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .partner-item {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 4px 14px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .partner-num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--gold);
}

.page-about .partner-name {
  margin: 0;
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .partner-role {
  grid-column: 2;
  margin: 6px 0 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: rgba(233, 226, 214, 0.75);
}

/* ---------- 联系路径 ---------- */
.page-about .contact-card {
  background: var(--paper);
  color: var(--ink);
  border-top: 3px solid var(--gold);
  padding: 28px 22px 26px;
}

.page-about .contact-grid {
  display: grid;
  gap: 26px;
}

.page-about .contact-text {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: rgba(18, 16, 15, 0.78);
}

.page-about .contact-text + .contact-text {
  margin-top: 14px;
}

.page-about .contact-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

.page-about .contact-list {
  list-style: none;
  display: grid;
  gap: 14px;
  margin: 0;
  padding: 0;
}

.page-about .contact-item {
  display: grid;
  gap: 4px;
  padding-bottom: 12px;
  border-bottom: 1px solid rgba(18, 16, 15, 0.14);
}

.page-about .contact-label {
  font-size: 11px;
  letter-spacing: 0.18em;
  color: rgba(18, 16, 15, 0.5);
}

.page-about .contact-value {
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: 0.01em;
  color: var(--ink);
  text-decoration: none;
  word-break: break-word;
}

.page-about a.contact-value:hover,
.page-about a.contact-value:focus-visible {
  color: var(--orange);
}

.page-about .contact-note {
  margin: 24px 0 0;
  padding-top: 16px;
  border-top: 1px solid rgba(18, 16, 15, 0.16);
  font-size: 13px;
  line-height: 1.8;
  color: rgba(18, 16, 15, 0.66);
}

.page-about .inline-link {
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid var(--gold);
}

.page-about .inline-link:hover,
.page-about .inline-link:focus-visible {
  color: var(--orange);
  border-bottom-color: var(--orange);
}

.page-about .btn {
  text-decoration: none;
}

/* ---------- 断点 ---------- */
@media (min-width: 600px) {
  .page-about .hero-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

  .page-about .code-legend > div {
    padding: 12px 14px 0 0;
    border-top: 1px solid rgba(201, 192, 178, 0.24);
    border-right: 1px solid rgba(201, 192, 178, 0.16);
  }

  .page-about .code-legend > div:last-child {
    border-right: 0;
  }
}

@media (min-width: 760px) {
  .page-about .team-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .contact-grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    gap: 44px;
  }

  .page-about .contact-card {
    padding: 34px 30px 30px;
  }

  .page-about .partner-item {
    grid-template-columns: 56px 190px minmax(0, 1fr);
    gap: 0 24px;
    align-items: baseline;
  }

  .page-about .partner-role {
    grid-column: 3;
    margin-top: 0;
  }
}

@media (min-width: 860px) {
  .page-about .about-shell {
    grid-template-columns: var(--about-rail-width) minmax(0, 1fr);
    gap: 60px;
    padding: 32px 40px 132px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 108px;
    align-self: start;
    border-top: 0;
    border-left: 1px solid var(--line);
    padding: 4px 0 4px 16px;
  }

  .page-about .rail-nav {
    flex-direction: column;
    gap: 13px;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .rail-link {
    white-space: normal;
    border-bottom: 0;
    border-left: 2px solid transparent;
    padding: 2px 0 2px 10px;
    margin-left: -17px;
  }

  .page-about .rail-link:hover,
  .page-about .rail-link:focus-visible {
    border-left-color: var(--gold);
    border-bottom-color: transparent;
  }

  .page-about .rail-edition {
    margin-left: -17px;
    padding-left: 10px;
  }

  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    gap: 52px;
    align-items: start;
  }

  .page-about .about-section {
    margin-top: 128px;
  }

  .page-about .timeline {
    padding-left: 34px;
  }

  .page-about .tl-node::before {
    left: -39px;
  }

  .page-about .tl-node--current::before {
    left: -41px;
  }
}

@media (min-width: 900px) {
  .page-about .timeline-wrap {
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
    gap: 52px;
    align-items: start;
  }

  .page-about .quality-wrap {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
    gap: 46px;
    align-items: start;
  }
}

@media (min-width: 1200px) {
  .page-about .about-shell {
    padding-left: 72px;
    padding-right: 72px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .status-dot {
    animation: none;
    opacity: 0.9;
  }

  .page-about .rail-link,
  .page-about .placard,
  .page-about .team-cell,
  .page-about .tl-mark::after {
    transition: none;
  }
}