.page-about {
  --about-rail-w: 248px;
  --about-axis: rgba(31, 107, 69, .5);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: 32px;
  padding-top: 28px;
}

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

.page-about .about-kicker {
  margin: 0;
  font-family: var(--mono);
  font-size: .75rem;
  letter-spacing: .16em;
  color: var(--turf-hi);
  text-transform: uppercase;
}

.page-about .about-title {
  margin: 12px 0 18px;
  font-family: var(--display);
  font-weight: 800;
  font-size: clamp(2.1rem, 8vw, 3.6rem);
  line-height: 1.04;
  letter-spacing: -.02em;
  color: var(--paper);
}

.page-about .about-lede {
  margin: 0;
  max-width: 62ch;
  font-size: 1.0625rem;
  line-height: 1.85;
  color: var(--mute);
}

/* ---------- 概览数字 ---------- */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 32px 0 0;
  padding: 0;
  background: var(--line);
  border: 1px solid var(--line);
  list-style: none;
}

.page-about .about-stat {
  display: flex;
  flex-direction: column-reverse;
  gap: 6px;
  min-width: 0;
  padding: 16px 18px;
  background: var(--ink-2);
}

.page-about .about-stat-num {
  margin: 0;
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
  font-size: 1.5rem;
  line-height: 1.1;
  color: var(--cyan);
}

.page-about .about-stat-label {
  margin: 0;
  font-size: .75rem;
  letter-spacing: .04em;
  color: var(--mute);
}

/* ---------- 竖排分卷索引 ---------- */
.page-about .vol-index {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--line);
}

.page-about .vol-index-head {
  margin: 0;
  flex: 0 0 auto;
  align-self: center;
  font-family: var(--mono);
  font-size: .6875rem;
  letter-spacing: .18em;
  color: var(--amber);
}

.page-about .vol-link {
  flex: 0 0 auto;
  font-size: .8125rem;
  color: var(--mute);
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--ease);
}

.page-about .vol-link:hover,
.page-about .vol-link:focus-visible {
  color: var(--turf-hi);
}

.page-about .vol-seq {
  font-family: var(--mono);
  font-size: .6875rem;
  color: var(--turf-hi);
  margin-right: 4px;
}

/* ---------- 版面骨架 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 36px;
  margin-top: 40px;
}

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

.page-about .chapter-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 18px;
}

.page-about .chapter-nav-link {
  display: block;
  padding: 4px 0;
  font-size: .875rem;
  color: var(--mute);
  text-decoration: none;
}

.page-about .chapter-nav-link:hover,
.page-about .chapter-nav-link:focus-visible {
  color: var(--turf-hi);
}

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

.page-about .about-sec {
  position: relative;
}

.page-about .about-sec .sec-sub {
  max-width: 60ch;
}

/* ---------- 档案立场 ---------- */
.page-about .stance-grid {
  display: grid;
  gap: 28px;
}

.page-about .stance-lead {
  margin: 0 0 16px;
  font-size: 1.125rem;
  line-height: 1.7;
  color: var(--paper);
}

.page-about .stance-text .prose p {
  margin: 0 0 16px;
  max-width: 68ch;
  line-height: 1.85;
  color: var(--mute);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 0;
  min-width: 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line);
  filter: saturate(.82) contrast(1.06);
}

.page-about .about-figure figcaption {
  margin-top: 10px;
  font-size: .8125rem;
  font-style: italic;
  line-height: 1.6;
  color: var(--mute);
}

/* ---------- 三条口径 ---------- */
.page-about .about-protocol {
  margin-top: 8px;
}

.page-about .card > .card-top-band {
  background: var(--turf);
}

.page-about .protocol-card {
  display: flex;
  flex-direction: column;
  padding: 22px 20px 20px;
}

.page-about .protocol-idx {
  margin: 0 0 8px;
  font-family: var(--mono);
  font-size: .6875rem;
  letter-spacing: .14em;
  color: var(--amber);
}

.page-about .protocol-name {
  margin: 0 0 12px;
  font-size: 1.0625rem;
  font-weight: 700;
  line-height: 1.45;
  color: var(--paper);
}

.page-about .protocol-say {
  margin: 0 0 14px;
  font-size: .9375rem;
  line-height: 1.75;
  color: var(--paper);
}

.page-about .protocol-trade {
  margin: 0 0 16px;
  padding-top: 14px;
  border-top: 1px solid var(--amber);
  font-size: .875rem;
  line-height: 1.75;
  color: var(--mute);
}

.page-about .protocol-key {
  display: inline-block;
  margin-right: 6px;
  font-family: var(--mono);
  font-size: .6875rem;
  letter-spacing: .1em;
  color: var(--amber);
}

/* ---------- 团队 ---------- */
.page-about .about-team {
  margin-top: 8px;
}

.page-about .about-team-card {
  position: relative;
  display: flex;
  flex-direction: column;
  padding: 22px 16px 18px;
  background: var(--ink-2);
  border: 1px solid var(--line);
}

.page-about .about-team-band {
  position: absolute;
  inset: 0 0 auto 0;
  height: 4px;
  background: var(--turf);
}

.page-about .about-team-count {
  margin: 0;
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
  font-size: 2rem;
  line-height: 1;
  color: var(--cyan);
}

.page-about .about-team-role {
  margin: 10px 0 8px;
  font-size: .9375rem;
  font-weight: 700;
  color: var(--paper);
}

.page-about .about-team-duty {
  margin: 0;
  font-size: .8125rem;
  line-height: 1.7;
  color: var(--mute);
}

.page-about .team-flow {
  display: grid;
  gap: 28px;
  margin-top: 36px;
}

.page-about .flow-steps {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 1px;
  background: var(--line);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .flow-step {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 14px;
  padding: 16px 4px;
  background: var(--ink);
}

.page-about .flow-mark {
  font-family: var(--mono);
  font-size: .75rem;
  color: var(--turf-hi);
}

.page-about .flow-name {
  margin: 0;
  font-size: .9375rem;
  font-weight: 700;
  color: var(--paper);
}

.page-about .flow-desc {
  flex: 1 1 260px;
  margin: 0;
  font-size: .875rem;
  line-height: 1.7;
  color: var(--mute);
}

/* ---------- 版本时间轴 ---------- */
.page-about .version-wrap {
  display: grid;
  gap: 32px;
}

.page-about .about-tl {
  margin: 8px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 4px;
}

.page-about .about-tl-item {
  position: relative;
  padding-left: 28px;
}

.page-about .about-tl-item::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 22px;
  bottom: -4px;
  width: 1px;
  background: var(--about-axis);
}

.page-about .about-tl-item:last-child::before {
  display: none;
}

.page-about .about-tl-node {
  position: absolute;
  left: 0;
  top: 18px;
  width: 11px;
  height: 11px;
  box-sizing: border-box;
  background: var(--ink);
  border: 2px solid var(--turf-hi);
  transform: rotate(45deg);
}

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

.page-about .about-version-sum {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 16px 4px;
  cursor: pointer;
  list-style: none;
}

.page-about .about-version-sum::-webkit-details-marker {
  display: none;
}

.page-about .about-version-tag {
  flex: 0 0 auto;
  padding: 2px 8px;
  font-family: var(--mono);
  font-size: .75rem;
  letter-spacing: .08em;
  color: var(--ink);
  background: var(--amber);
}

.page-about .about-version-name {
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--paper);
}

.page-about .about-version-cue {
  margin-left: auto;
  font-family: var(--mono);
  font-size: 1rem;
  color: var(--turf-hi);
}

.page-about .about-version-cue::after {
  content: "+";
}

.page-about .about-version[open] .about-version-cue::after {
  content: "\2212";
}

.page-about .about-version-body {
  padding: 0 4px 20px;
}

.page-about .about-version-lede {
  margin: 0 0 10px;
  font-size: .9375rem;
  line-height: 1.75;
  color: var(--paper);
}

.page-about .about-version-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 6px;
}

.page-about .about-version-list li {
  position: relative;
  padding-left: 16px;
  font-size: .875rem;
  line-height: 1.75;
  color: var(--mute);
}

.page-about .about-version-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .75em;
  width: 6px;
  height: 1px;
  background: var(--turf-hi);
}

/* ---------- 边界清单 ---------- */
.page-about .about-excl {
  margin-top: 12px;
  border: 1px solid var(--line);
  background: var(--ink-2);
}

.page-about .about-excl-sum {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 16px 18px;
  cursor: pointer;
  list-style: none;
  border-bottom: 1px solid transparent;
}

.page-about .about-excl-sum::-webkit-details-marker {
  display: none;
}

.page-about .about-excl[open] .about-excl-sum {
  border-bottom-color: var(--line);
}

.page-about .about-excl-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--paper);
}

.page-about .about-excl-count {
  font-family: var(--mono);
  font-size: .75rem;
  color: var(--amber);
}

.page-about .about-excl-cue {
  margin-left: auto;
  font-family: var(--mono);
  color: var(--turf-hi);
}

.page-about .about-excl-cue::after {
  content: "\2212";
}

.page-about .about-excl:not([open]) .about-excl-cue::after {
  content: "+";
}

.page-about .about-excl-list {
  margin: 0;
  padding: 6px 18px 14px;
  list-style: none;
}

.page-about .about-excl-item {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 12px;
  padding: 9px 0;
  border-bottom: 1px solid rgba(242, 239, 230, .07);
  font-family: var(--mono);
  font-size: .8125rem;
  line-height: 1.6;
}

.page-about .about-excl-item:last-child {
  border-bottom: none;
}

.page-about .about-x {
  flex: 0 0 auto;
  color: var(--amber);
}

.page-about .about-excl-name {
  color: var(--paper);
}

.page-about .about-excl-why {
  flex: 1 1 200px;
  color: var(--mute);
  font-family: var(--sans);
  font-style: italic;
}

.page-about .about-excl .footnote {
  margin: 0;
  padding: 0 18px 18px;
}

/* ---------- 档案去向 ---------- */
.page-about .about-routes {
  margin: 12px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 1px;
  background: var(--line);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-route {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 16px;
  padding: 18px 6px;
  background: var(--ink);
  transition: background var(--ease);
}

.page-about .about-route:hover {
  background: var(--ink-2);
}

.page-about .about-route-idx {
  font-family: var(--mono);
  font-size: .75rem;
  color: var(--turf-hi);
}

.page-about .about-route-name {
  font-size: 1rem;
  font-weight: 700;
  color: var(--paper);
  text-decoration: none;
  border-bottom: 1px solid var(--turf);
  transition: color var(--ease), border-color var(--ease);
}

.page-about .about-route-name:hover,
.page-about .about-route-name:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .about-route-desc {
  flex: 1 1 280px;
  font-size: .875rem;
  line-height: 1.75;
  color: var(--mute);
}

/* ---------- 窄屏 → 宽屏 ---------- */
@media (min-width: 720px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .stance-grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .team-flow {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 40px;
    align-items: start;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 48px;
    padding-top: 48px;
  }

  .page-about .vol-index {
    writing-mode: vertical-rl;
    flex-direction: row;
    justify-content: flex-start;
    gap: 16px;
    overflow: visible;
    padding: 0 0 0 18px;
    border-bottom: none;
    border-left: 1px solid var(--line);
  }

  .page-about .vol-index-head {
    align-self: auto;
  }

  .page-about .vol-seq {
    display: block;
    margin: 0 0 4px;
  }
}

@media (min-width: 1000px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: 56px;
    margin-top: 56px;
  }

  .page-about .rail-inner {
    position: sticky;
    top: calc(var(--head-h-sm) + 24px);
  }

  .page-about .chapter-nav {
    flex-direction: column;
    gap: 2px;
  }

  .page-about .chapter-nav-link {
    padding: 6px 0 6px 10px;
    border-left: 2px solid transparent;
  }

  .page-about .chapter-nav-link:hover,
  .page-about .chapter-nav-link:focus-visible {
    border-left-color: var(--turf-hi);
  }

  .page-about .about-body {
    position: relative;
    padding-left: 56px;
  }

  .page-about .about-body::before {
    content: "";
    position: absolute;
    left: 18px;
    top: 10px;
    bottom: 60px;
    width: 1px;
    background: linear-gradient(180deg, rgba(62, 156, 99, .85), rgba(31, 107, 69, .12));
  }

  .page-about .about-sec::before {
    content: "";
    position: absolute;
    left: -44px;
    top: 10px;
    width: 12px;
    height: 12px;
    box-sizing: border-box;
    background: var(--ink);
    border: 2px solid var(--turf-hi);
    transform: rotate(45deg);
  }
}

@media (min-width: 1160px) {
  .page-about .version-wrap {
    grid-template-columns: minmax(0, 1fr) 300px;
    gap: 44px;
    align-items: start;
  }

  .page-about .version-figure {
    position: sticky;
    top: calc(var(--head-h-sm) + 24px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .vol-link,
  .page-about .about-route,
  .page-about .about-route-name {
    transition: none;
  }
}