.page-about {
  position: relative;
  isolation: isolate;
  background: var(--bg);
}

.page-about::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    linear-gradient(to right, rgba(41, 52, 74, 0.38) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(41, 52, 74, 0.38) 1px, transparent 1px);
  background-size: 40px 40px, 40px 40px;
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.85), rgba(0, 0, 0, 0.22) 34%, rgba(0, 0, 0, 0.8));
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.85), rgba(0, 0, 0, 0.22) 34%, rgba(0, 0, 0, 0.8));
}

.page-about .wrap {
  position: relative;
  z-index: 1;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: 24px 0 44px;
  border-bottom: 1px solid var(--line);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: -30% -12% auto -12%;
  height: 150%;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(48% 52% at 84% 14%, rgba(53, 225, 228, 0.13), transparent 68%),
    radial-gradient(44% 50% at 4% 2%, rgba(29, 107, 255, 0.2), transparent 66%);
}

.page-about .about-hero .wrap {
  z-index: 1;
}

.page-about .crumbs {
  margin-bottom: 22px;
}

.page-about .hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
  align-items: end;
}

.page-about .hero-title {
  margin: 10px 0 0;
  font-size: clamp(40px, 9vw, 84px);
  font-weight: 200;
  line-height: 0.98;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .hero-lead {
  margin: 18px 0 0;
  max-width: 34em;
  font-size: 16px;
  line-height: 27px;
  color: var(--mist);
}

.page-about .hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 20px;
}

.page-about .hero-media {
  border: 1px solid var(--line);
}

/* ---------- 通用区段 ---------- */

.page-about .band {
  position: relative;
  padding: clamp(36px, 6vw, 72px) 0;
  border-bottom: 1px solid var(--line);
}

.page-about .section-head {
  display: grid;
  gap: 10px;
  max-width: 46em;
  margin-bottom: 28px;
}

.page-about .section-title {
  margin: 0;
  font-size: clamp(24px, 3.4vw, 34px);
  font-weight: 600;
  line-height: 1.22;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .section-lead {
  margin: 0;
  max-width: 36em;
  font-size: 15px;
  line-height: 25px;
  color: var(--mist);
}

/* ---------- 数字带 ---------- */

.page-about .figures-band .eyebrow {
  margin-bottom: 14px;
}

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

.page-about .figure {
  display: grid;
  gap: 6px;
  align-content: start;
  padding: 20px 16px 18px;
  background: var(--panel);
}

.page-about .figure:first-child {
  background:
    linear-gradient(180deg, rgba(29, 107, 255, 0.18), rgba(21, 28, 41, 0) 74%),
    var(--panel);
}

.page-about .figure-value {
  font-family: var(--font-mono);
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .figure-label {
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--cyan);
}

.page-about .figure-note {
  font-size: 13px;
  line-height: 20px;
  color: var(--mist);
}

.page-about .trend-frame {
  margin: 24px 0 0;
  border: 1px solid var(--line);
}

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

/* ---------- 时间轴 ---------- */

.page-about .story-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 22px;
}

.page-about .rail-title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mist);
}

.page-about .rail-track {
  list-style: none;
  margin: 0;
  padding: 0 0 10px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  border-bottom: 1px solid var(--line);
}

.page-about .rail-track li {
  flex: 0 0 auto;
}

.page-about .rail-node {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  white-space: nowrap;
  font-size: 13px;
  color: var(--mist);
  text-decoration: none;
  transition: color 140ms var(--ease), border-color 140ms var(--ease), background-color 140ms var(--ease);
}

.page-about .rail-node:hover,
.page-about .rail-node:focus-visible {
  color: var(--paper);
  border-color: var(--blue);
  background: var(--focus);
}

.page-about .rail-idx {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  color: var(--blue);
}

.page-about .stage {
  position: relative;
  display: grid;
  gap: 14px;
  padding: 22px 18px 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
}

.page-about .stage + .stage {
  margin-top: 16px;
}

.page-about .stage::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--line);
}

.page-about .stage--glass {
  border-color: rgba(53, 225, 228, 0.2);
  background:
    linear-gradient(180deg, rgba(243, 240, 232, 0.07), rgba(243, 240, 232, 0.015)),
    var(--panel);
}

.page-about #stage-entry::before {
  background: var(--mist);
}

.page-about #stage-docs::before {
  background: var(--blue);
}

.page-about #stage-multi::before {
  background: var(--cyan);
}

.page-about #stage-self::before {
  background: var(--clay);
}

.page-about .stage-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px;
}

.page-about .stage-version {
  font-family: var(--font-mono);
  font-size: 34px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--blue);
}

.page-about .stage-title {
  margin: 0;
  font-size: 19px;
  font-weight: 600;
  line-height: 1.35;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .stage-text {
  margin: 0;
  max-width: 40em;
  font-size: 15px;
  line-height: 25px;
  color: var(--mist);
}

.page-about .stage-points {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
  max-width: 42em;
}

.page-about .stage-points li {
  position: relative;
  padding-left: 18px;
  font-size: 14px;
  line-height: 22px;
  color: var(--paper);
}

.page-about .stage-points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 9px;
  height: 1px;
  background: var(--cyan);
}

.page-about .disclosure {
  margin-top: 2px;
  border-top: 1px solid var(--line);
}

.page-about .disclosure-inner p {
  margin: 0;
  max-width: 40em;
  font-size: 14px;
  line-height: 23px;
  color: var(--mist);
}

/* ---------- 文档体系 ---------- */

.page-about .doc-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.page-about .doc-card {
  position: relative;
  display: grid;
  gap: 10px;
  align-content: start;
  padding: 20px 16px;
  border: 1px solid var(--line);
  background: var(--panel);
}

.page-about .doc-card::before {
  content: "";
  position: absolute;
  left: -1px;
  right: -1px;
  top: -1px;
  height: 2px;
  background: var(--blue);
}

.page-about .doc-card:nth-child(2)::before {
  background: var(--cyan);
}

.page-about .doc-card:nth-child(3)::before {
  background: var(--moss);
}

.page-about .doc-card:nth-child(4)::before {
  background: var(--clay);
}

.page-about .doc-card-meta {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mist);
}

.page-about .doc-card-title {
  margin: 0;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .doc-card p {
  margin: 0;
  font-size: 14px;
  line-height: 22px;
  color: var(--mist);
}

.page-about .doc-card .doc-card-link {
  padding-top: 10px;
  border-top: 1px dashed var(--line);
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--cyan);
}

.page-about .docs-frame {
  margin: 26px 0 0;
  border: 1px solid var(--line);
}

/* ---------- 校对 ---------- */

.page-about .review-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .review-item {
  display: grid;
  gap: 8px;
  align-content: start;
  padding: 20px 16px;
  background: var(--panel);
}

.page-about .review-head {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin: 0;
}

.page-about .review-num {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  color: var(--blue);
}

.page-about .review-title {
  font-size: 16px;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .review-text {
  margin: 0;
  max-width: 40em;
  font-size: 14px;
  line-height: 23px;
  color: var(--mist);
}

/* ---------- 维护分工 ---------- */

.page-about .crew-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.page-about .crew-card {
  display: grid;
  gap: 8px;
  align-content: start;
  padding: 20px 16px;
  border: 1px solid var(--line);
  background:
    linear-gradient(180deg, rgba(53, 225, 228, 0.06), rgba(21, 28, 41, 0) 62%),
    var(--panel);
}

.page-about .crew-count {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 28px;
  font-weight: 700;
  line-height: 1;
  color: var(--cyan);
}

.page-about .crew-role {
  margin: 0;
  font-size: 16px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .crew-text {
  margin: 0;
  font-size: 14px;
  line-height: 22px;
  color: var(--mist);
}

/* ---------- 备案与咨询 ---------- */

.page-about .registry {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
}

.page-about .registry-list {
  margin: 0;
  padding: 0 0 0 16px;
  border-left: 1px solid var(--line);
}

.page-about .registry-list .contact-row {
  display: grid;
  gap: 3px;
  padding: 10px 0;
  border-bottom: 1px dashed var(--line);
}

.page-about .registry-list .contact-row:last-child {
  border-bottom: 0;
}

.page-about .registry-list .contact-key {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--mist);
}

.page-about .registry-list .contact-val {
  margin: 0;
  font-size: 15px;
  line-height: 24px;
  color: var(--paper);
}

.page-about .registry-list .contact-val.mono {
  font-family: var(--font-mono);
  letter-spacing: 0.01em;
}

.page-about .registry-side {
  display: grid;
  gap: 16px;
  align-content: start;
}

.page-about .registry-note {
  margin: 0;
  padding-left: 16px;
  border-left: 2px solid var(--line);
  font-size: 14px;
  line-height: 23px;
  color: var(--mist);
}

.page-about .registry-links {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin: 0;
}

/* ---------- 引用规范 ---------- */

.page-about .cite-panel {
  display: grid;
  gap: 12px;
  padding: 22px 18px;
  border: 1px solid var(--line);
  border-left: 2px solid var(--clay);
  background: var(--panel);
}

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

.page-about .cite-list li {
  display: grid;
  grid-template-columns: 32px minmax(0, 1fr);
  gap: 10px;
  align-items: baseline;
  font-size: 14px;
  line-height: 23px;
  color: var(--paper);
}

.page-about .cite-num {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  color: var(--cyan);
}

.page-about .crosslinks {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 26px;
  margin-top: 26px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
}

/* ---------- 响应式 ---------- */

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

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

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

  .page-about .figure-value {
    font-size: 38px;
  }

  .page-about .stage {
    padding: 26px 24px 24px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    padding: 32px 0 64px;
  }

  .page-about .hero-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.02fr);
    gap: 48px;
  }

  .page-about .figures {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .registry {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    gap: 48px;
  }
}

@media (min-width: 960px) {
  .page-about .story-layout {
    grid-template-columns: 212px minmax(0, 1fr);
    gap: 52px;
  }

  .page-about .rail {
    position: sticky;
    top: calc(var(--header-h) + 32px);
    align-self: start;
    margin-bottom: 0;
  }

  .page-about .rail-track {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding: 0 0 0 20px;
    border-bottom: 0;
    position: relative;
  }

  .page-about .rail-track::before {
    content: "";
    position: absolute;
    left: 5px;
    top: 6px;
    bottom: 6px;
    width: 1px;
    background: linear-gradient(180deg, var(--blue), var(--cyan) 48%, var(--clay));
    opacity: 0.72;
  }

  .page-about .rail-track li {
    flex: none;
  }

  .page-about .rail-node {
    display: flex;
    align-items: baseline;
    position: relative;
    padding: 11px 0;
    border: 0;
    border-radius: 0;
    font-size: 14px;
    background: none;
  }

  .page-about .rail-node::before {
    content: "";
    position: absolute;
    left: -20px;
    top: 21px;
    width: 10px;
    height: 1px;
    background: var(--line);
    transition: background-color 140ms var(--ease);
  }

  .page-about .rail-node:hover,
  .page-about .rail-node:focus-visible {
    background: none;
    color: var(--paper);
  }

  .page-about .rail-node:hover::before,
  .page-about .rail-node:focus-visible::before {
    background: var(--cyan);
  }
}

@media (min-width: 1100px) {
  .page-about .doc-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .stage-version {
    font-size: 46px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .rail-node,
  .page-about .rail-node::before {
    transition: none;
  }
}