.page-about {
  --about-rail: 208px;
  padding-bottom: 76px;
}

.page-about .crumbs {
  padding-block: 18px 0;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: 24px;
  padding-block: 24px 36px;
  border-bottom: 1px solid var(--c-line);
}

.page-about .about-hero__kicker {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--c-cyan);
  margin: 0 0 10px;
}

.page-about .about-hero__title {
  font-family: var(--f-head);
  font-size: 26px;
  line-height: 1.24;
  letter-spacing: -0.01em;
  color: var(--c-bone);
  margin: 0 0 12px;
  max-width: 24ch;
}

.page-about .about-hero__sub {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.6;
  color: var(--c-muted);
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 20px 0 0;
  background: var(--c-line);
  border: 1px solid var(--c-line);
}

.page-about .about-facts > div {
  background: var(--c-ink);
  padding: 10px 12px;
}

.page-about .about-facts dt {
  font-size: 12px;
  color: var(--c-muted);
  margin: 0 0 4px;
}

.page-about .about-facts dd {
  margin: 0;
  font-family: var(--f-mono);
  font-variant-numeric: tabular-nums;
  font-size: 17px;
  color: var(--c-bone);
  letter-spacing: 0.01em;
}

.page-about .about-hero__frame {
  position: relative;
  border: 1px solid var(--c-line);
  background: var(--c-panel);
}

.page-about .about-hero__frame img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 9 / 7;
  object-fit: cover;
}

/* ---------- 主体两栏 ---------- */
.page-about .about-body {
  display: grid;
  gap: 26px;
  padding-block: 34px 0;
}

.page-about .about-toc {
  border: 1px solid var(--c-line);
  background: var(--c-panel);
  padding: 14px 14px 16px;
}

.page-about .about-toc__title {
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--c-cyan);
  margin: 0 0 10px;
}

.page-about .about-toc ol {
  list-style: none;
  counter-reset: toc;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
}

.page-about .about-toc li {
  counter-increment: toc;
}

.page-about .about-toc a {
  display: block;
  padding: 7px 8px;
  border-left: 2px solid transparent;
  font-size: 13px;
  line-height: 1.4;
  color: var(--c-muted);
  text-decoration: none;
  transition: color var(--t-fast) linear, border-color var(--t-fast) linear;
}

.page-about .about-toc a::before {
  content: counter(toc, decimal-leading-zero) "  ";
  font-family: var(--f-mono);
  color: var(--c-cyan);
  opacity: 0.65;
}

.page-about .about-toc a:hover,
.page-about .about-toc a:focus-visible {
  color: var(--c-bone);
  border-left-color: var(--c-cyan-2);
  outline: none;
}

.page-about .about-toc__note {
  margin: 12px 0 0;
  padding-top: 10px;
  border-top: 1px solid var(--c-line);
  font-size: 12px;
  line-height: 1.5;
  color: var(--c-muted);
}

/* ---------- 正文小节 ---------- */
.page-about .about-flow {
  display: grid;
}

.page-about .about-flow > section {
  padding-block: 30px 36px;
  border-top: 1px solid var(--c-line);
}

.page-about .about-flow > section:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .ab-kicker {
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--c-cyan);
  margin: 0 0 8px;
}

.page-about .ab-h2 {
  font-family: var(--f-head);
  font-size: 20px;
  line-height: 1.3;
  letter-spacing: -0.005em;
  color: var(--c-bone);
  margin: 0 0 14px;
}

.page-about .ab-p {
  font-size: 15px;
  line-height: 1.6;
  color: var(--c-bone);
  margin: 0 0 12px;
  max-width: 76ch;
}

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

.page-about .ab-muted {
  color: var(--c-muted);
  font-size: 13.5px;
  line-height: 1.6;
}

.page-about .ab-p a {
  color: var(--c-cyan);
  text-decoration: none;
  border-bottom: 1px solid var(--c-line);
  transition: border-color var(--t-fast) linear;
}

.page-about .ab-p a:hover,
.page-about .ab-p a:focus-visible {
  border-bottom-color: var(--c-cyan);
  outline: none;
}

/* ---------- 版本年表带 ---------- */
.page-about .about-timeline {
  display: flex;
  gap: 12px;
  overflow-x: auto;
  scroll-snap-type: x proximity;
  padding: 6px 2px 14px;
  margin-top: 18px;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-timeline::-webkit-scrollbar {
  height: 4px;
}

.page-about .about-timeline::-webkit-scrollbar-track {
  background: var(--c-line);
}

.page-about .about-timeline::-webkit-scrollbar-thumb {
  background: var(--c-cyan);
}

.page-about .about-node {
  flex: 0 0 236px;
  scroll-snap-align: start;
  position: relative;
  border: 1px solid var(--c-line);
  background: var(--c-panel);
  padding: 20px 14px 14px;
  transition: border-color var(--t-base) var(--ease);
}

.page-about .about-node::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 14px;
  width: 10px;
  height: 10px;
  background: var(--c-cyan);
}

.page-about .about-node:hover,
.page-about .about-node:focus {
  border-color: var(--c-cyan);
  outline: none;
}

.page-about .about-node__ver {
  display: block;
  font-size: 22px;
  line-height: 1;
  color: var(--c-cyan);
  margin-bottom: 10px;
}

.page-about .about-node__title {
  font-family: var(--f-head);
  font-size: 16px;
  color: var(--c-bone);
  margin: 0 0 8px;
}

.page-about .about-node__sum {
  font-size: 13px;
  line-height: 1.55;
  color: var(--c-muted);
  margin: 0;
}

.page-about .about-node__more {
  font-size: 12px;
  line-height: 1.5;
  color: var(--c-amber);
  margin: 10px 0 0;
  padding-top: 8px;
  border-top: 1px dashed var(--c-line);
}

/* ---------- 团队表 ---------- */
.page-about .about-tablewrap {
  margin-top: 18px;
  overflow-x: auto;
}

.page-about .about-team {
  width: 100%;
  min-width: 540px;
  border-collapse: collapse;
  font-size: 14px;
}

.page-about .about-team caption {
  caption-side: top;
  text-align: left;
  font-size: 12px;
  color: var(--c-muted);
  padding-bottom: 8px;
}

.page-about .about-team th,
.page-about .about-team td {
  text-align: left;
  padding: 10px;
  border-bottom: 1px solid var(--c-line);
  vertical-align: top;
  line-height: 1.5;
}

.page-about .about-team thead th {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--c-muted);
  font-weight: 400;
}

.page-about .about-team tbody th {
  color: var(--c-bone);
  font-weight: 600;
  white-space: nowrap;
}

.page-about .about-team tbody td {
  color: var(--c-muted);
}

.page-about .about-team td.mono {
  color: var(--c-cyan);
  font-size: 16px;
  width: 72px;
}

.page-about .about-team .about-team__total th,
.page-about .about-team .about-team__total td {
  border-bottom: 0;
  border-top: 1px solid var(--c-cyan);
}

/* ---------- 口径注解块 ---------- */
.page-about .about-note {
  border-left: 2px solid var(--c-cyan);
  background: linear-gradient(90deg, rgba(53, 240, 200, 0.07), rgba(53, 240, 200, 0));
  padding: 12px 14px;
  margin: 0 0 10px;
}

.page-about .about-note summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  cursor: pointer;
  list-style: none;
  font-size: 14px;
  line-height: 1.5;
  color: var(--c-bone);
}

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

.page-about .about-note summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--f-mono);
  font-size: 15px;
  color: var(--c-cyan);
  transition: transform var(--t-base) var(--ease);
}

.page-about .about-note[open] summary::after {
  transform: rotate(45deg);
}

.page-about .about-note summary:focus-visible {
  outline: 1px solid var(--c-cyan);
  outline-offset: 3px;
}

.page-about .about-note__body {
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px dashed var(--c-line);
  font-size: 13px;
  line-height: 1.6;
  color: var(--c-muted);
}

/* ---------- 图与流程图 ---------- */
.page-about .about-figure {
  margin: 22px 0 0;
}

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

.page-about .about-figure figcaption {
  margin-top: 8px;
  font-size: 12px;
  line-height: 1.5;
  color: var(--c-muted);
}

.page-about .about-checkwrap {
  margin-top: 22px;
  border: 1px solid var(--c-line);
  background: var(--c-panel);
  padding: 14px;
}

.page-about .about-checkwrap__title {
  margin: 0 0 6px;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--c-cyan);
}

.page-about .about-check {
  display: block;
  width: 100%;
  height: auto;
  min-width: 0;
}

.page-about .about-checkwrap__cap {
  margin: 8px 0 0;
  font-size: 12px;
  line-height: 1.5;
  color: var(--c-muted);
}

/* ---------- 内容分区列表 ---------- */
.page-about .about-zones {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
  border-top: 1px solid var(--c-line);
}

.page-about .about-zone {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 10px;
  align-items: start;
  padding: 14px 0;
  border-bottom: 1px solid var(--c-line);
}

.page-about .about-zone__idx {
  font-size: 15px;
  color: var(--c-cyan);
  padding-top: 2px;
}

.page-about .about-zone__name {
  font-family: var(--f-head);
  font-size: 16px;
  margin: 0 0 6px;
  line-height: 1.35;
}

.page-about .about-zone__name a {
  color: var(--c-bone);
  text-decoration: none;
  border-bottom: 1px solid var(--c-line);
  transition: color var(--t-fast) linear, border-color var(--t-fast) linear;
}

.page-about .about-zone__name a:hover,
.page-about .about-zone__name a:focus-visible {
  color: var(--c-cyan-2);
  border-bottom-color: var(--c-cyan);
  outline: none;
}

.page-about .about-zone__desc {
  margin: 0;
  font-size: 13px;
  line-height: 1.58;
  color: var(--c-muted);
}

.page-about .about-zone__freq {
  grid-column: 2;
  justify-self: start;
  margin-top: 8px;
}

/* ---------- 边界清单 ---------- */
.page-about .about-limits {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-limits li {
  position: relative;
  padding: 11px 12px 11px 34px;
  border: 1px solid var(--c-line);
  background: var(--c-ink);
  font-size: 14px;
  line-height: 1.6;
  color: var(--c-bone);
}

.page-about .about-limits li::before {
  content: "";
  position: absolute;
  left: 12px;
  top: 18px;
  width: 10px;
  height: 10px;
  background: var(--c-flare);
}

.page-about .about-limits + .ab-p {
  margin-top: 16px;
}

/* ---------- 平板与桌面 ---------- */
@media (min-width: 720px) {
  .page-about .about-hero__title {
    font-size: 32px;
  }

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

  .page-about .about-node {
    flex: 0 0 258px;
  }

  .page-about .about-zone {
    grid-template-columns: 34px minmax(0, 1fr) auto;
    gap: 14px;
    align-items: center;
  }

  .page-about .about-zone__freq {
    grid-column: 3;
    margin-top: 0;
    justify-self: end;
  }

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

@media (min-width: 960px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    align-items: start;
    gap: 40px;
    padding-block: 30px 44px;
  }

  .page-about .about-hero__title {
    font-size: 34px;
    max-width: 22ch;
  }

  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 44px;
    padding-block: 44px 0;
  }

  .page-about .about-toc {
    position: sticky;
    top: 24px;
  }

  .page-about .about-flow > section {
    padding-block: 34px 42px;
  }

  .page-about .ab-h2 {
    font-size: 22px;
  }

  .page-about .about-checkwrap {
    padding: 18px 20px;
  }
}

@media (hover: hover) and (min-width: 960px) {
  .page-about .about-node__more {
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    margin-top: 0;
    padding-top: 0;
    border-top-color: transparent;
    transition: max-height var(--t-base) var(--ease),
      opacity var(--t-base) linear,
      margin-top var(--t-base) linear,
      padding-top var(--t-base) linear;
  }

  .page-about .about-node:hover .about-node__more,
  .page-about .about-node:focus .about-node__more,
  .page-about .about-node:focus-within .about-node__more {
    max-height: 8em;
    opacity: 1;
    margin-top: 10px;
    padding-top: 8px;
    border-top-color: var(--c-line);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-node,
  .page-about .about-toc a,
  .page-about .about-zone__name a,
  .page-about .about-note summary::after {
    transition: none;
  }
}