.page-about {
  --about-rule: rgba(11, 59, 46, .16);
  --about-rule-soft: rgba(11, 59, 46, .09);
  --about-signal-soft: rgba(245, 197, 24, .14);
  overflow-x: clip;
}

/* ---------- 首屏 ---------- */
.page-about .about-head {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  padding: clamp(1.75rem, 4.5vw, 3rem) 0 clamp(2rem, 5vw, 3rem);
}

.page-about .about-head__lead {
  max-width: 46rem;
}

.page-about .about-head h1 {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(1.95rem, 6.2vw, 3.5rem);
  line-height: 1.06;
  letter-spacing: .01em;
  color: var(--pitch);
  margin: .6rem 0 0;
  text-wrap: balance;
}

.page-about .about-head .lede {
  margin-top: 1.1rem;
  max-width: 34em;
  color: var(--ink);
}

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

.page-about .about-head__facts > div {
  background: var(--chrome);
  padding: .85rem 1rem;
}

.page-about .about-head__facts dt {
  margin: 0 0 .3rem;
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--pitch-2);
}

.page-about .about-head__facts dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(1.05rem, 3vw, 1.35rem);
  font-weight: 700;
  color: var(--ink);
}

/* ---------- 锚点目录 ---------- */
.page-about .about-index {
  border-top: 3px solid var(--pitch);
  border-bottom: 1px solid var(--about-rule);
  padding: .85rem 0;
  background: var(--chrome);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0 0 .15rem;
  display: flex;
  gap: .5rem;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-index__list li {
  flex: none;
}

.page-about .about-index__list a {
  display: inline-flex;
  align-items: baseline;
  gap: .55rem;
  padding: .45rem .85rem;
  border: 1px solid var(--chalk);
  background: #fff;
  color: var(--pitch);
  font-size: .9rem;
  text-decoration: none;
  white-space: nowrap;
  transition: border-color 160ms var(--ease), background-color 160ms var(--ease), color 160ms var(--ease);
}

.page-about .about-index__list a .mono {
  font-size: .72rem;
  color: var(--pitch-2);
  transition: color 160ms var(--ease);
}

.page-about .about-index__list a:hover,
.page-about .about-index__list a:focus-visible {
  border-color: var(--pitch);
  background: var(--signal);
  color: var(--pitch);
}

.page-about .about-index__list a:hover .mono,
.page-about .about-index__list a:focus-visible .mono {
  color: var(--pitch);
}

.page-about .about-index__list a:focus-visible {
  outline: 3px solid var(--varblue);
  outline-offset: 2px;
}

/* ---------- 分区底色 ---------- */
.page-about .about-band {
  padding: clamp(2.25rem, 6vw, 4.5rem) 0;
}

.page-about .about-band--chalk {
  background: var(--chalk);
}

.page-about .about-band--cream {
  background: var(--cream);
}

.page-about .about-band--deep {
  background: linear-gradient(140deg, var(--pitch) 0%, var(--night) 100%);
  color: var(--chrome);
}

/* ---------- 章节骨架 ---------- */
.page-about .about-sec__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

.page-about .about-sec__index {
  display: flex;
  align-items: center;
  gap: .6rem;
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--pitch-2);
}

.page-about .about-sec__index .index-num {
  display: inline-grid;
  place-items: center;
  min-width: 2.1rem;
  height: 2.1rem;
  padding: 0 .35rem;
  background: var(--pitch);
  color: var(--signal);
  font-size: .8rem;
  font-weight: 700;
  letter-spacing: .04em;
}

.page-about .about-sec__body h2 {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(1.4rem, 4.2vw, 2.1rem);
  line-height: 1.18;
  letter-spacing: .01em;
  color: var(--pitch);
  margin: 0 0 1rem;
  max-width: 22ch;
}

.page-about .about-sec__body .prose {
  max-width: 33em;
}

.page-about .about-sec__body .prose p + p {
  margin-top: .9rem;
}

.page-about .about-sec__body .prose a {
  color: var(--pitch);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
  transition: color 140ms var(--ease), text-decoration-color 140ms var(--ease);
}

.page-about .about-sec__body .prose a:hover,
.page-about .about-sec__body .prose a:focus-visible {
  color: var(--red);
}

.page-about .media-frame {
  margin: 0;
}

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

/* ---------- 强调引用 ---------- */
.page-about .about-callout {
  margin-top: 1.6rem;
  border: 3px solid var(--pitch);
  border-left-width: 12px;
  background: var(--chrome);
  padding: 1.1rem 1.2rem 1.15rem 1.35rem;
  box-shadow: var(--shadow-hard);
}

.page-about .about-callout p {
  margin: .35rem 0 0;
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 700;
  color: var(--ink);
  line-height: 1.6;
}

/* ---------- 深色区块内部 ---------- */
.page-about .about-band--deep .about-sec__index {
  color: rgba(244, 247, 245, .72);
}

.page-about .about-band--deep .about-sec__index .index-num {
  background: var(--signal);
  color: var(--pitch);
}

.page-about .about-band--deep h2 {
  color: var(--chrome);
}

.page-about .about-band--deep .prose {
  color: rgba(244, 247, 245, .84);
}

.page-about .about-band--deep .prose a {
  color: var(--signal);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

/* ---------- 差异标记列表 ---------- */
.page-about .about-list {
  list-style: none;
  margin: 1.75rem 0 0;
  padding: 0;
  max-width: 33em;
}

.page-about .about-list li {
  display: grid;
  gap: .35rem;
  padding: .9rem 0;
  border-top: 1px solid rgba(244, 247, 245, .26);
}

.page-about .about-list li:last-child {
  border-bottom: 1px solid rgba(244, 247, 245, .26);
}

.page-about .about-list .mono {
  font-size: .78rem;
  letter-spacing: .14em;
  color: var(--signal);
  text-transform: uppercase;
}

.page-about .about-list p {
  margin: 0;
  color: rgba(244, 247, 245, .84);
}

/* ---------- 表格 ---------- */
.page-about .about-tablewrap {
  margin: 1.5rem 0 1.6rem;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border-top: 3px solid var(--pitch);
}

.page-about .about-codes,
.page-about .about-roster {
  width: 100%;
  border-collapse: collapse;
  font-size: .95rem;
  background: transparent;
}

.page-about .about-codes caption,
.page-about .about-roster caption {
  text-align: left;
  padding: .7rem 0 .55rem;
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--pitch-2);
}

.page-about .about-codes th,
.page-about .about-codes td,
.page-about .about-roster th,
.page-about .about-roster td {
  padding: .62rem .55rem;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--about-rule);
}

.page-about .about-codes thead th,
.page-about .about-roster thead th {
  background: var(--pitch);
  color: var(--chrome);
  font-family: var(--font-mono);
  font-size: .68rem;
  font-weight: 500;
  letter-spacing: .12em;
  text-transform: uppercase;
  border-bottom: none;
  white-space: nowrap;
}

.page-about .about-codes tbody td.mono {
  font-size: .88rem;
  font-weight: 700;
  color: var(--pitch);
  white-space: nowrap;
}

.page-about .about-roster td.num,
.page-about .about-roster th.num {
  text-align: right;
  white-space: nowrap;
}

.page-about .about-roster td.num {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--pitch);
}

.page-about .about-roster tbody tr:hover {
  background: var(--about-signal-soft);
}

/* ---------- 审核流程 details ---------- */
.page-about .about-flow {
  margin-top: 1.75rem;
  border: 2px solid var(--pitch);
  background: var(--chrome);
  max-width: 40em;
}

.page-about .about-flow > summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: .7rem;
  padding: .9rem 1rem;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1rem;
  line-height: 1.4;
  color: var(--pitch);
  transition: background-color 160ms var(--ease);
}

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

.page-about .about-flow > summary::before {
  content: "+";
  flex: none;
  display: grid;
  place-items: center;
  width: 1.6rem;
  height: 1.6rem;
  background: var(--signal);
  color: var(--pitch);
  font-family: var(--font-mono);
  font-size: 1.1rem;
  font-weight: 700;
}

.page-about .about-flow[open] > summary::before {
  content: "\2013";
}

.page-about .about-flow > summary:hover,
.page-about .about-flow > summary:focus-visible {
  background: var(--about-signal-soft);
}

.page-about .about-flow > summary:focus-visible {
  outline: 3px solid var(--varblue);
  outline-offset: -3px;
}

.page-about .about-flow__list {
  margin: 0;
  padding: .35rem 1rem 1.1rem;
  list-style: none;
  display: grid;
  gap: .7rem;
  border-top: 1px dashed var(--about-rule);
}

.page-about .about-flow__list li {
  position: relative;
  padding-left: 1.15rem;
  color: var(--ink);
  font-size: .95rem;
  line-height: 1.65;
}

.page-about .about-flow__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .62em;
  width: .5rem;
  height: .5rem;
  background: var(--chalk);
  border: 1px solid var(--pitch);
}

.page-about .about-flow__list .mono {
  display: block;
  font-size: .74rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--pitch-2);
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: 1.6rem 0 1.5rem;
  padding: 0;
  max-width: 40em;
}

.page-about .about-timeline li {
  position: relative;
  display: grid;
  gap: .25rem;
  padding: .85rem 0 .85rem 1.15rem;
  border-left: 2px solid var(--chalk);
  transition: border-color 160ms var(--ease), background-color 160ms var(--ease);
}

.page-about .about-timeline li::before {
  content: "";
  position: absolute;
  left: -6px;
  top: 1.28rem;
  width: 10px;
  height: 10px;
  background: var(--chrome);
  border: 2px solid var(--pitch);
  transition: background-color 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .about-timeline li:hover,
.page-about .about-timeline li:focus-within {
  border-left-color: var(--signal);
  background: var(--about-signal-soft);
}

.page-about .about-timeline li:hover::before,
.page-about .about-timeline li:focus-within::before {
  background: var(--signal);
  border-color: var(--pitch);
}

.page-about .about-timeline__year {
  font-size: .78rem;
  font-weight: 700;
  letter-spacing: .12em;
  color: var(--pitch-2);
}

.page-about .about-timeline__body h3 {
  margin: 0 0 .2rem;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.02rem;
  letter-spacing: .01em;
  color: var(--pitch);
}

.page-about .about-timeline__body p {
  margin: 0;
  font-size: .95rem;
  line-height: 1.65;
  color: var(--ink);
}

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

  .page-about .about-timeline {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: .35rem 1.75rem;
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 980px) {
  .page-about .about-head {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
    align-items: end;
    gap: 3.5rem;
  }

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

  .page-about .about-sec__grid {
    grid-template-columns: 5rem minmax(0, 1.4fr) minmax(0, 1fr);
    gap: 2.5rem;
    align-items: start;
  }

  .page-about .about-sec__index {
    flex-direction: column;
    align-items: flex-start;
    gap: .55rem;
    position: sticky;
    top: 7rem;
  }

  .page-about .about-sec__grid.about-sec--wide {
    grid-template-columns: 5rem minmax(0, 3fr);
  }

  .page-about .about-sec__aside {
    margin-top: .35rem;
  }

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

@media (prefers-reduced-motion: reduce) {
  .page-about .about-index__list a,
  .page-about .about-timeline li,
  .page-about .about-timeline li::before,
  .page-about .about-flow > summary,
  .page-about .about-sec__body .prose a {
    transition: none;
  }
}