.page-about {
  --ab-rail: 196px;
  background: var(--ink-900);
  color: var(--gry-300);
  overflow-x: hidden;
}

.page-about .breadcrumb { padding-top: 20px; }

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: 28px 0 40px;
  border-bottom: 1px solid var(--ink-600);
  background: linear-gradient(180deg, rgba(15, 227, 200, 0.055), rgba(15, 227, 200, 0) 62%);
}

.page-about .about-hero__eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 18px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--gry-500);
}

.page-about .about-hero__coord {
  display: inline-flex;
  align-items: center;
  padding: 2px 7px;
  border: 1px solid var(--cy-500);
  color: var(--cy-500);
  font-size: 11px;
  letter-spacing: 0.1em;
}

.page-about .about-hero__title {
  margin: 0 0 20px;
  max-width: 22ch;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 30px;
  line-height: 1.18;
  letter-spacing: -0.02em;
  color: var(--paper-100);
}

.page-about .about-hero__lead {
  margin: 0 0 28px;
  max-width: 64ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--gry-300);
}

.page-about .about-hero__meta {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  max-width: 620px;
  background: var(--ink-600);
  border: 1px solid var(--ink-600);
}

.page-about .about-hero__meta > div {
  background: var(--ink-900);
  padding: 12px 14px;
}

.page-about .about-hero__meta dt {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--gry-500);
}

.page-about .about-hero__meta dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 19px;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.01em;
  color: var(--cy-500);
}

/* ---------- 布局 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 30px;
  padding: 36px 0 72px;
  align-items: start;
}

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

/* ---------- 索引栏 ---------- */
.page-about .about-rail {
  min-width: 0;
  padding: 14px 14px 12px;
  background: var(--ink-800);
  border: 1px solid var(--ink-600);
  border-left: 2px solid var(--cy-500);
}

.page-about .about-rail__head {
  margin: 0 0 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--ink-600);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--gry-500);
}

.page-about .about-rail__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 12px;
  padding: 0;
  list-style: none;
}

.page-about .about-rail__link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border: 1px solid var(--ink-600);
  background: var(--ink-900);
  color: var(--gry-300);
  font-size: 14px;
  text-decoration: none;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .about-rail__no {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--gry-500);
  transition: color var(--dur) var(--ease);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  border-color: var(--cy-500);
  background: var(--ink-600);
  color: var(--cy-200);
}

.page-about .about-rail__link:hover .about-rail__no,
.page-about .about-rail__link:focus-visible .about-rail__no { color: var(--cy-500); }

.page-about .about-rail__foot {
  margin: 0;
  padding-top: 10px;
  border-top: 1px solid var(--ink-600);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--gry-500);
}

/* ---------- 章节框架 ---------- */
.page-about .sec {
  padding-top: 40px;
  margin-top: 40px;
  border-top: 1px solid var(--ink-600);
}

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

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

.page-about .sec__eyebrow {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--gry-500);
}

.page-about .sec__eyebrow b {
  font-weight: 400;
  color: var(--cy-500);
}

.page-about .sec__head h2 {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 23px;
  line-height: 1.25;
  letter-spacing: -0.01em;
  color: var(--paper-100);
}

.page-about .sec__lead {
  margin: 0;
  max-width: 66ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--gry-500);
}

.page-about .sec p {
  font-size: 15px;
  line-height: 1.78;
  color: var(--gry-300);
}

/* ---------- A1 定位声明 ---------- */
.page-about .about-claim {
  padding-left: 18px;
  border-left: 2px solid var(--cy-500);
  background: linear-gradient(90deg, rgba(15, 227, 200, 0.06), rgba(15, 227, 200, 0) 68%);
}

.page-about .about-claim__text {
  margin: 0 0 20px;
  max-width: 62ch;
}

.page-about .about-claim__list {
  display: grid;
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--ink-600);
  border: 1px solid var(--ink-600);
}

.page-about .about-claim__list li {
  padding: 13px 14px;
  background: var(--ink-900);
  font-size: 14px;
  line-height: 1.7;
  color: var(--gry-300);
}

.page-about .about-claim__k {
  display: inline-block;
  min-width: 74px;
  margin-right: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--cy-500);
}

/* ---------- 图片容器 ---------- */
.page-about .about-figure {
  margin: 0 0 26px;
  border: 1px solid var(--ink-600);
  background: var(--ink-800);
  overflow: hidden;
}

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

.page-about .about-figure--trace img { aspect-ratio: 2 / 1; }
.page-about .about-figure--check img { aspect-ratio: 4 / 3; }
.page-about .about-figure--region img { aspect-ratio: 1 / 1; }

.page-about .about-figure .media__cap {
  display: block;
  padding: 8px 12px;
  border-top: 1px solid var(--ink-600);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--gry-500);
}

/* ---------- A2 版本时间线 ---------- */
.page-about .verlist { display: grid; }

.page-about .ver {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  padding: 20px 0;
}

.page-about .ver__mark {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.page-about .ver__no {
  font-family: var(--font-mono);
  font-size: 22px;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--cy-500);
  font-variant-numeric: tabular-nums;
}

.page-about .ver__stage {
  padding-left: 8px;
  border-left: 2px solid var(--ink-600);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--gry-500);
}

.page-about .ver__body h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 18px;
  letter-spacing: -0.01em;
  color: var(--paper-100);
}

.page-about .ver__body p {
  margin: 0 0 12px;
  font-size: 15px;
  line-height: 1.78;
  color: var(--gry-300);
}

.page-about .ver__body p.ver__field {
  margin: 0;
  padding-top: 9px;
  border-top: 1px dashed var(--ink-600);
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.6;
  letter-spacing: 0.04em;
  color: var(--gry-500);
}

.page-about .ver--current .ver__no { color: var(--or-500); }

.page-about .ver--current .ver__body p.ver__field {
  border-top-style: solid;
  border-top-color: var(--ink-600);
}

/* 分隔带 */
.page-about .band {
  position: relative;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 2px 0;
}

.page-about .band__coord {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--gry-500);
  white-space: nowrap;
}

.page-about .band__rule {
  flex: 1 1 auto;
  min-width: 12px;
  height: 1px;
  background: var(--cy-500);
  opacity: 0.42;
}

.page-about .band__quip {
  font-family: var(--font-display);
  font-size: 14px;
  letter-spacing: 0.05em;
  color: var(--cy-200);
  white-space: nowrap;
}

.page-about .band__tip {
  position: absolute;
  right: 0;
  bottom: calc(100% + 6px);
  z-index: 3;
  padding: 4px 9px;
  border: 1px solid var(--cy-500);
  background: var(--ink-800);
  color: var(--cy-200);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  white-space: nowrap;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity var(--dur) var(--ease), visibility var(--dur) var(--ease);
}

.page-about .band:hover .band__tip {
  opacity: 1;
  visibility: visible;
}

/* ---------- A3 口径与校核 ---------- */
.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  margin-bottom: 28px;
}

.page-about .checks {
  display: grid;
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--ink-600);
  border: 1px solid var(--ink-600);
}

.page-about .check {
  padding: 16px 15px;
  background: var(--ink-900);
}

.page-about .check__no {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--cy-500);
}

.page-about .check h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 17px;
  color: var(--paper-100);
}

.page-about .check p {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--gry-500);
}

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

.page-about .fields {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
}

.page-about .fields h3 {
  margin: 0 0 12px;
  padding-bottom: 9px;
  border-bottom: 1px solid var(--ink-600);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0.1em;
  color: var(--gry-500);
}

.page-about .fields ul {
  display: grid;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .fields li {
  position: relative;
  padding-left: 15px;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  color: var(--gry-300);
}

.page-about .fields li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.62em;
  width: 7px;
  height: 1px;
  background: var(--cy-500);
}

/* ---------- A4 合并决策 ---------- */
.page-about .about-merge > p {
  max-width: 68ch;
  margin: 0 0 22px;
}

.page-about .merge-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 0 0 22px;
  padding: 0;
  list-style: none;
  background: var(--ink-600);
  border: 1px solid var(--ink-600);
}

.page-about .merge-list li {
  padding: 13px 14px;
  background: var(--ink-800);
  font-size: 14px;
  line-height: 1.7;
  color: var(--gry-300);
}

.page-about .merge-list__k {
  display: inline-block;
  min-width: 52px;
  margin-right: 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--gry-500);
}

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

/* ---------- A5 团队 ---------- */
.page-about .teams {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin-bottom: 20px;
  background: var(--ink-600);
  border: 1px solid var(--ink-600);
}

.page-about .team {
  padding: 18px 15px;
  background: var(--ink-900);
}

.page-about .team__no {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--gry-500);
}

.page-about .team h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 17px;
  color: var(--paper-100);
}

.page-about .team__num {
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 26px;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  color: var(--cy-500);
}

.page-about .team__num span {
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--gry-500);
}

.page-about .team p {
  margin: 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--gry-500);
}

.page-about .note {
  margin: 0;
  padding: 13px 15px;
  border: 1px solid var(--ink-600);
  border-left: 2px solid var(--or-500);
  background: var(--ink-800);
  font-size: 13px;
  line-height: 1.72;
  color: var(--gry-300);
}

.page-about .note .note__label {
  margin-right: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--or-200);
}

/* ---------- A6 观察名录 ---------- */
.page-about .about-observe > p {
  max-width: 68ch;
  margin: 0 0 22px;
}

.page-about .observe-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--ink-600);
  border: 1px solid var(--ink-600);
}

.page-about .observe-cell {
  padding: 16px 15px;
  background: var(--ink-900);
}

.page-about .observe-cell__n {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 24px;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  color: var(--cy-200);
}

.page-about .observe-cell__l {
  display: block;
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--gry-500);
}

/* ---------- A7 备案与联系 ---------- */
.page-about .about-registry {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
}

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

.page-about .idcard {
  padding: 22px 18px;
  background: var(--paper-100);
  border: 1px solid var(--cy-500);
  color: var(--ink-900);
}

.page-about .idcard__label {
  margin: 0 0 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid rgba(6, 18, 15, 0.16);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--clay-500);
}

.page-about .idcard dl {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin: 0;
}

.page-about .idcard dt {
  margin-bottom: 5px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: #55655f;
}

.page-about .idcard dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.55;
  word-break: break-word;
  color: var(--ink-900);
}

.page-about .idcard__note {
  margin: 18px 0 0;
  padding-top: 14px;
  border-top: 1px solid rgba(6, 18, 15, 0.16);
  font-size: 12px;
  line-height: 1.72;
  color: #45544f;
}

.page-about .idcard__links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  margin: 14px 0 0;
}

.page-about .idcard__links a {
  font-size: 13px;
  color: var(--clay-500);
  text-decoration: none;
  border-bottom: 1px solid currentColor;
  transition: color var(--dur) var(--ease);
}

.page-about .idcard__links a:hover,
.page-about .idcard__links a:focus-visible { color: var(--ink-900); }

/* ---------- A8 继续 ---------- */
.page-about .about-next__list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--ink-600);
  border: 1px solid var(--ink-600);
}

.page-about .about-next__list li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 14px;
  padding: 15px 16px;
  background: var(--ink-900);
  transition: background-color var(--dur) var(--ease);
}

.page-about .about-next__list li:hover { background: var(--ink-800); }

.page-about .about-next__list a {
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 600;
  letter-spacing: 0.01em;
  color: var(--cy-500);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color var(--dur) var(--ease);
}

.page-about .about-next__list a:hover,
.page-about .about-next__list a:focus-visible { border-bottom-color: var(--cy-500); }

.page-about .about-next__list span {
  font-size: 13px;
  color: var(--gry-500);
}

/* ---------- 焦点可见 ---------- */
.page-about a:focus-visible {
  outline: 1px solid var(--cy-500);
  outline-offset: 2px;
}

/* ---------- 平板与桌面 ---------- */
@media (min-width: 640px) {
  .page-about .about-hero__meta { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .page-about .observe-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .page-about .merge-list { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .page-about .teams { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .page-about .about-next__list { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .page-about .idcard dl { grid-template-columns: 96px minmax(0, 1fr); gap: 12px 14px; }
  .page-about .idcard dt { margin-bottom: 0; padding-top: 3px; }
}

@media (min-width: 900px) {
  .page-about .about-layout {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: 44px;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--frame-top) + 16px);
  }

  .page-about .about-rail__list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 1px;
    background: var(--ink-600);
    border: 1px solid var(--ink-600);
  }

  .page-about .about-rail__link {
    width: 100%;
    justify-content: flex-start;
    border: 0;
    background: var(--ink-800);
    padding: 10px 12px;
  }

  .page-about .about-rail__link:hover,
  .page-about .about-rail__link:focus-visible { background: var(--ink-600); }

  .page-about .ver {
    grid-template-columns: 128px minmax(0, 1fr);
    gap: 32px;
    padding: 26px 0;
  }

  .page-about .ver__mark {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
    position: sticky;
    top: calc(var(--frame-top) + 16px);
    align-self: start;
  }

  .page-about .ver__stage {
    padding-left: 0;
    border-left: 0;
    padding-top: 6px;
    border-top: 1px solid var(--ink-600);
    width: 100%;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1fr) 320px;
    gap: 32px;
    align-items: start;
  }

  .page-about .fields { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 34px; }

  .page-about .about-registry {
    grid-template-columns: 260px minmax(0, 1fr);
    gap: 32px;
    align-items: start;
  }

  .page-about .about-hero__title { font-size: 36px; }
  .page-about .sec__head h2 { font-size: 26px; }
}

@media (min-width: 1200px) {
  .page-about { --ab-rail: 216px; }
  .page-about .about-hero { padding: 40px 0 52px; }
  .page-about .about-hero__title { font-size: 40px; }
  .page-about .teams { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .page-about .about-next__list { grid-template-columns: repeat(4, minmax(0, 1fr)); }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail__link,
  .page-about .band__tip,
  .page-about .idcard__links a,
  .page-about .about-next__list li,
  .page-about .about-next__list a {
    transition: none;
  }
}