.page-about {
  --about-ink-soft: #3D3D50;
  font-family: var(--font-body);
  color: var(--ink);
  background-color: var(--paper);
  line-height: 1.5;
  overflow-x: hidden;
}

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

.page-about .page-shell {
  max-width: 1280px;
  margin-inline: auto;
  padding-inline: 1rem;
}

.page-about .section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: .4rem 1rem;
  margin-bottom: 1.5rem;
}

.page-about .section-eyebrow {
  font-family: var(--font-num);
  font-weight: 700;
  letter-spacing: .1em;
  font-size: .78rem;
  text-transform: uppercase;
  color: var(--blue-ink);
}

.page-about .section-title {
  font-size: 1.8rem;
  font-weight: 900;
  margin: 0;
  line-height: 1.2;
}

.page-about .section-note {
  font-size: .85rem;
  color: var(--magenta-ink);
  font-weight: 700;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: 2.25rem 0 2rem;
}

.page-about .hero-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

.page-about .breadcrumb {
  margin-bottom: 1rem;
}

.page-about .hero-title {
  font-size: clamp(1.85rem, 5vw, 3.2rem);
  font-weight: 900;
  line-height: 1.15;
  border-left: 10px solid var(--yellow);
  padding-left: 1rem;
}

.page-about .hero-title-sub {
  display: block;
  font-size: clamp(1rem, 2vw, 1.4rem);
  color: var(--magenta-ink);
  margin-top: .6rem;
}

.page-about .hero-desc {
  max-width: 42rem;
  color: var(--about-ink-soft);
  margin-top: 1.1rem;
  font-size: .95rem;
}

.page-about .hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
  margin-top: 1.25rem;
}

.page-about .hero-index {
  display: grid;
  gap: 1rem;
}

.page-about .hero-tiles {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: .8rem;
}

.page-about .hero-tile {
  border: 3px solid var(--ink);
  box-shadow: 5px 5px 0 var(--ink);
  padding: 1rem .9rem .8rem;
  display: flex;
  flex-direction: column;
}

.page-about .hero-tile .ht-num {
  font-family: var(--font-num);
  font-weight: 900;
  font-size: 1.9rem;
  line-height: 1;
}

.page-about .hero-tile .ht-name {
  margin-top: .4rem;
  font-weight: 900;
  font-size: .85rem;
}

.page-about .hero-tile.tile-orange { background-color: var(--orange); }
.page-about .hero-tile.tile-cyan { background-color: var(--cyan); }
.page-about .hero-tile.tile-yellow { background-color: var(--yellow); }
.page-about .hero-tile.tile-magenta { background-color: var(--magenta); }
.page-about .hero-tile.tile-blue { background-color: var(--blue); }
.page-about .hero-tile.tile-violet { background-color: var(--violet); }

.page-about .hero-version {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
}

.page-about .hv-block {
  border: 2px solid var(--ink);
  background: var(--yellow);
  box-shadow: 3px 3px 0 var(--ink);
  padding: .4rem .7rem;
  display: flex;
  gap: .45rem;
  align-items: baseline;
  font-size: .78rem;
}

.page-about .hv-block strong {
  font-family: var(--font-num);
  font-size: 1rem;
}

.page-about .hv-label {
  opacity: .7;
}

/* ---------- 收录范围 ---------- */
.page-about .scope-band {
  background: var(--dg-green);
  padding: 3rem 0;
  color: var(--white);
}

.page-about .scope-band .section-title { color: var(--white); }
.page-about .scope-band .section-eyebrow { color: var(--cyan); }
.page-about .scope-band .section-note { color: var(--yellow); }

.page-about .scope-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

.page-about .scope-item {
  background: var(--white);
  color: var(--ink);
  border: 3px solid var(--ink);
  padding: 1rem 1.1rem;
  display: grid;
  grid-template-columns: auto 1fr auto;
  grid-template-areas:
    "idx name count"
    "desc desc desc";
  gap: .2rem .8rem;
}

.page-about .scope-item-cyan { box-shadow: 6px 6px 0 var(--cyan); }
.page-about .scope-item-orange { box-shadow: 6px 6px 0 var(--orange); }
.page-about .scope-item-magenta { box-shadow: 6px 6px 0 var(--magenta); }
.page-about .scope-item-violet { box-shadow: 6px 6px 0 var(--violet); }
.page-about .scope-item-blue { box-shadow: 6px 6px 0 var(--blue); }
.page-about .scope-item-yellow { box-shadow: 6px 6px 0 var(--yellow); }

.page-about .scope-index {
  grid-area: idx;
  font-family: var(--font-num);
  font-weight: 900;
  font-size: 1.15rem;
  color: var(--cyan-ink);
}

.page-about .scope-item-orange .scope-index { color: var(--change-ink); }
.page-about .scope-item-magenta .scope-index { color: var(--magenta-ink); }
.page-about .scope-item-violet .scope-index { color: var(--violet-ink); }
.page-about .scope-item-blue .scope-index { color: var(--blue-ink); }
.page-about .scope-item-yellow .scope-index { color: var(--change-ink); }

.page-about .scope-name {
  grid-area: name;
  font-weight: 900;
  font-size: 1.1rem;
}

.page-about .scope-count {
  grid-area: count;
  font-family: var(--font-num);
  font-weight: 900;
  font-size: 1.4rem;
  border: 2px solid var(--ink);
  background: var(--yellow);
  padding: .05rem .45rem;
  line-height: 1.3;
}

.page-about .scope-desc {
  grid-area: desc;
  margin-top: .5rem;
  font-size: .85rem;
  color: var(--about-ink-soft);
}

.page-about .scope-meter-row {
  margin-top: 2rem;
  display: grid;
  gap: 1rem;
}

.page-about .tier-ladder {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: .5rem;
}

.page-about .tier-step {
  background: var(--ink);
  border: 2px solid var(--white);
  padding: .5rem .75rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: .85rem;
  font-weight: 700;
}

.page-about .tier-step-free { background: var(--ok-ink); }
.page-about .tier-step-pay { background: var(--blue-ink); }
.page-about .tier-step-sub { background: var(--violet-ink); }
.page-about .tier-step-iap { background: var(--magenta-ink); }

.page-about .tier-val {
  font-family: var(--font-num);
  font-weight: 900;
  font-size: 1.2rem;
}

.page-about .status-legend {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  align-items: center;
}

/* ---------- 目录结构与更新机制 ---------- */
.page-about .structure-band {
  background: var(--paper);
  padding: 3rem 0;
}

.page-about .info-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

.page-about .info-col {
  min-width: 0;
}

.page-about .col-title {
  font-size: 1.4rem;
  font-weight: 900;
  margin: 0 0 1rem;
  padding-left: .8rem;
  border-left: 8px solid var(--magenta);
}

.page-about .catalog-tree {
  background: var(--white);
  border: 3px solid var(--ink);
  box-shadow: 8px 8px 0 var(--cyan);
  padding: 1.25rem;
}

.page-about .tree-top {
  display: flex;
  align-items: center;
  gap: .75rem;
  background: var(--db-blue);
  padding: .75rem;
  color: var(--white);
  margin-bottom: 1.25rem;
  border: 2px solid var(--ink);
}

.page-about .tree-root-icon {
  flex-shrink: 0;
  width: 2.6rem;
  height: 2.6rem;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--yellow);
  color: var(--ink);
  border: 2px solid var(--ink);
  font-weight: 900;
  font-size: 1.4rem;
}

.page-about .tree-top-name {
  font-weight: 900;
  font-size: 1.05rem;
  display: block;
}

.page-about .tree-top-note {
  font-size: .78rem;
  color: rgba(255, 255, 255, .7);
  display: block;
  margin-top: .2rem;
}

.page-about .tree-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .tree-list > li {
  margin-bottom: .45rem;
}

.page-about .tree-node {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .5rem;
  padding: .6rem .75rem;
  border: 2px solid var(--ink);
  background: var(--paper);
  font-weight: 900;
  cursor: pointer;
  list-style: none;
}

.page-about .tree-node::-webkit-details-marker {
  display: none;
}

.page-about .tree-node::before {
  content: "▾";
  font-family: var(--font-num);
  font-size: .85rem;
  color: var(--blue-ink);
  flex-shrink: 0;
  transition: transform .2s ease;
}

.page-about details[open] > .tree-node::before {
  transform: rotate(180deg);
}

.page-about .tree-node-c1 { border-left: 10px solid var(--orange); }
.page-about .tree-node-c2 { border-left: 10px solid var(--cyan); }
.page-about .tree-node-c3 { border-left: 10px solid var(--yellow); }
.page-about .tree-node-c4 { border-left: 10px solid var(--magenta); }
.page-about .tree-node-c5 { border-left: 10px solid var(--violet); }
.page-about .tree-node-c6 { border-left: 10px solid var(--blue); }

.page-about .tree-node-title {
  font-size: .95rem;
  margin-right: auto;
  padding-left: .25rem;
}

.page-about .tree-count {
  font-family: var(--font-num);
  font-weight: 700;
  font-size: .78rem;
  background: var(--ink);
  color: var(--white);
  padding: .1rem .4rem;
}

.page-about .tree-sublist {
  list-style: none;
  margin: .4rem 0 .8rem 1.5rem;
  padding: 0 .5rem 0 1rem;
  border-left: 3px solid var(--cyan);
}

.page-about .tree-leaf {
  font-size: .9rem;
  padding: .35rem 0;
  display: flex;
  gap: .5rem;
  align-items: center;
}

.page-about .tl-price-tag {
  font-family: var(--font-num);
  font-weight: 900;
  font-size: .78rem;
  border: 1px solid var(--ink);
  background: var(--yellow);
  padding: .05rem .35rem;
}

.page-about .catalog-figure {
  border: 3px solid var(--ink);
  box-shadow: 6px 6px 0 var(--magenta);
  background: var(--white);
  margin: 1.25rem 0 0;
  padding: .5rem;
}

.page-about .catalog-figure figcaption {
  font-family: var(--font-num);
  font-size: .78rem;
  font-weight: 700;
  padding: .5rem .25rem 0;
}

.page-about .tree-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: .5rem;
  margin-top: .75rem;
}

.page-about .tree-stat {
  background: var(--yellow);
  border: 2px solid var(--ink);
  padding: .5rem .25rem;
  text-align: center;
  font-size: .75rem;
  font-weight: 700;
}

.page-about .tree-stat strong {
  display: block;
  font-family: var(--font-num);
  font-size: 1.35rem;
  line-height: 1;
}

/* ---------- 更新机制时间轴 ---------- */
.page-about .update-timeline {
  position: relative;
}

.page-about .tl-entry {
  display: flex;
  gap: .75rem;
  position: relative;
  padding-bottom: 1.6rem;
}

.page-about .tl-entry::before {
  content: "";
  position: absolute;
  left: 14px;
  top: 30px;
  bottom: 0;
  width: 3px;
  background: rgba(26, 26, 46, .18);
}

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

.page-about .tl-axis {
  flex-shrink: 0;
  width: 30px;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.page-about .tl-dot {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  border: 3px solid var(--ink);
  background: var(--change);
  z-index: 1;
}

.page-about .tl-dot-change { background: var(--change); }
.page-about .tl-dot-stop { background: var(--stop); }

.page-about .tl-code {
  font-family: var(--font-num);
  font-size: .7rem;
  font-weight: 900;
  color: var(--blue-ink);
  margin-top: .4rem;
  text-align: center;
  white-space: nowrap;
}

.page-about .tl-card {
  flex: 1;
  background: var(--white);
  color: var(--ink);
  border: 3px solid var(--ink);
  box-shadow: 5px 5px 0 var(--yellow);
  padding: 1rem;
  min-width: 0;
}

.page-about .tl-title {
  font-size: 1.05rem;
  font-weight: 900;
  margin: 0 0 .45rem;
}

.page-about .tl-summary {
  font-size: .85rem;
  color: var(--about-ink-soft);
  margin: 0 0 .75rem;
}

.page-about .tl-batch-list {
  list-style: none;
  margin: 0 0 .6rem;
  padding: 0;
}

.page-about .tl-batch-list li {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .5rem;
  border-bottom: 1px dashed var(--ink);
  padding: .4rem 0;
  font-size: .85rem;
}

.page-about .batch-tag {
  font-family: var(--font-num);
  font-weight: 900;
  font-size: .75rem;
  background: var(--cyan);
  border: 1px solid var(--ink);
  padding: .05rem .35rem;
}

.page-about .tl-status {
  display: inline-block;
  margin-top: .25rem;
}

.page-about .timeline-figure {
  margin: 0 0 1rem;
  background: var(--ink);
  border: 3px solid var(--ink);
  box-shadow: 6px 6px 0 var(--change);
  padding: .4rem;
}

.page-about .timeline-figure figcaption {
  font-family: var(--font-num);
  font-size: .78rem;
  font-weight: 700;
  color: var(--white);
  padding: .5rem .25rem 0;
}

.page-about .update-rules {
  background: var(--dg-green);
  border: 3px solid var(--ink);
  box-shadow: 6px 6px 0 var(--cyan);
  padding: 1rem;
  color: var(--white);
}

.page-about .rule-row {
  display: flex;
  justify-content: space-between;
  padding: .55rem 0;
  border-bottom: 1px solid rgba(255, 255, 255, .22);
  font-size: .85rem;
}

.page-about .rule-row:last-child {
  border-bottom: 0;
}

.page-about .rule-key {
  color: var(--yellow);
  font-weight: 700;
}

.page-about .rule-val {
  font-family: var(--font-num);
  font-weight: 900;
  font-size: 1.1rem;
}

/* ---------- 检索与筛选 ---------- */
.page-about .searchway-band {
  background: var(--db-blue);
  color: var(--white);
  padding: 3rem 0;
}

.page-about .searchway-band .section-title { color: var(--white); }
.page-about .searchway-band .section-eyebrow { color: var(--yellow); }
.page-about .searchway-band .section-note { color: var(--cyan); }

.page-about .searchway-head-wrap {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
}

.page-about .search-figure {
  margin: 0;
  border: 3px solid var(--ink);
  box-shadow: 6px 6px 0 var(--violet);
  background: var(--yellow);
  padding: .25rem;
  flex-shrink: 0;
}

.page-about .method-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
  margin-top: 2rem;
}

.page-about .method-card {
  background: var(--white);
  color: var(--ink);
  border: 3px solid var(--ink);
  padding: 1.1rem 1rem;
}

.page-about .method-card:nth-child(1) { box-shadow: 6px 6px 0 var(--cyan); }
.page-about .method-card:nth-child(2) { box-shadow: 6px 6px 0 var(--yellow); }
.page-about .method-card:nth-child(3) { box-shadow: 6px 6px 0 var(--orange); }
.page-about .method-card:nth-child(4) { box-shadow: 6px 6px 0 var(--magenta); }
.page-about .method-card:nth-child(5) { box-shadow: 6px 6px 0 var(--violet); }
.page-about .method-card:nth-child(6) { box-shadow: 6px 6px 0 var(--blue); }

.page-about .method-icon {
  width: 3.2rem;
  height: 3.2rem;
  border: 2px solid var(--ink);
  background: var(--yellow);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: .75rem;
}

.page-about .method-card:nth-child(1) .method-icon { background: var(--cyan); }
.page-about .method-card:nth-child(2) .method-icon { background: var(--yellow); }
.page-about .method-card:nth-child(3) .method-icon { background: var(--orange); }
.page-about .method-card:nth-child(4) .method-icon { background: var(--magenta); }
.page-about .method-card:nth-child(5) .method-icon { background: var(--violet); }
.page-about .method-card:nth-child(6) .method-icon { background: var(--blue); }

.page-about .method-icon svg {
  width: 1.6rem;
  height: 1.6rem;
  fill: none;
  stroke: var(--ink);
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.page-about .method-card:nth-child(5) .method-icon svg,
.page-about .method-card:nth-child(6) .method-icon svg {
  stroke: var(--white);
}

.page-about .method-card h3 {
  font-size: 1rem;
  font-weight: 900;
  margin: 0 0 .4rem;
}

.page-about .method-card p {
  font-size: .85rem;
  color: var(--about-ink-soft);
  margin: 0 0 .8rem;
  line-height: 1.5;
}

.page-about .method-card .btn {
  font-size: .82rem;
  padding: .45rem .7rem;
  text-decoration: none;
}

/* ---------- 栏目快速跳转 ---------- */
.page-about .linkout-band {
  background: var(--ink);
  padding: 3rem 0 2.5rem;
}

.page-about .linkout-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
  margin-bottom: 2rem;
}

.page-about .linkout-card {
  display: block;
  background: var(--paper);
  color: var(--ink);
  border: 3px solid var(--ink);
  padding: 1.1rem 1.25rem;
  text-decoration: none;
  transition: transform .15s ease, box-shadow .15s ease;
}

.page-about .linkout-card:nth-child(1) { box-shadow: 6px 6px 0 var(--cyan); }
.page-about .linkout-card:nth-child(2) { box-shadow: 6px 6px 0 var(--magenta); }
.page-about .linkout-card:nth-child(3) { box-shadow: 6px 6px 0 var(--yellow); }

.page-about .linkout-card:hover {
  transform: translate(-2px, -2px);
  box-shadow: 8px 8px 0 var(--violet);
}

.page-about .linkout-index {
  font-family: var(--font-num);
  font-weight: 900;
  font-size: .85rem;
  color: var(--blue-ink);
}

.page-about .linkout-title {
  display: block;
  font-weight: 900;
  font-size: 1.25rem;
  margin-top: .25rem;
}

.page-about .linkout-note {
  display: block;
  font-size: .82rem;
  color: var(--about-ink-soft);
  margin-top: .3rem;
}

.page-about .pagination-dummy {
  display: flex;
  flex-wrap: wrap;
  gap: .4rem;
  justify-content: center;
}

.page-about .pagination-dummy .page-num {
  text-decoration: none;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .scope-list {
    grid-template-columns: 1fr 1fr;
  }

  .page-about .tier-ladder {
    grid-template-columns: repeat(4, 1fr);
  }

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

@media (min-width: 960px) {
  .page-about .page-shell {
    padding-inline: 1.5rem;
  }

  .page-about .hero-layout {
    grid-template-columns: minmax(0, 7fr) minmax(0, 6fr);
    align-items: center;
    gap: 2.5rem;
  }

  .page-about .info-split {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
    align-items: start;
    gap: 2.5rem;
  }

  .page-about .scope-meter-row {
    grid-template-columns: 1.3fr 1fr;
    align-items: start;
  }

  .page-about .method-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 1.3rem;
  }

  .page-about .linkout-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 1.3rem;
  }
}