.page-about {
  --about-border: rgba(255, 255, 255, 0.16);
  --about-line: rgba(255, 255, 255, 0.35);
  --about-shadow: rgba(17, 17, 17, 0.55);
  padding: 0 0 80px;
}

/* ===== 页面 Hero ===== */
.page-about .about-hero {
  margin: clamp(16px, 4vw, 32px) 0 clamp(40px, 6vw, 64px);
  padding: clamp(28px, 5vw, 56px);
  background: linear-gradient(135deg, rgba(74, 35, 90, 0.75) 0%, rgba(26, 37, 47, 0.92) 60%, rgba(26, 37, 47, 0.65) 100%);
  border: 3px solid var(--color-ink);
  border-radius: 16px;
  box-shadow: 8px 8px 0 var(--color-ink);
  position: relative;
  overflow: hidden;
}

.page-about .about-hero::after {
  content: '';
  position: absolute;
  right: -40px;
  top: -40px;
  width: 180px;
  height: 180px;
  background: repeating-linear-gradient(45deg, var(--color-accent) 0 8px, transparent 8px 16px);
  opacity: 0.12;
  border-radius: 24px;
  transform: rotate(8deg);
  pointer-events: none;
}

.page-about .about-kicker {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.18em;
  color: var(--color-accent);
  text-transform: uppercase;
  margin: 0 0 10px;
  font-weight: 700;
}

.page-about .about-hero h1 {
  font-family: var(--font-head);
  font-size: clamp(30px, 5vw, 52px);
  font-weight: 900;
  color: var(--color-text);
  line-height: 1.15;
  margin: 0 0 16px;
}

.page-about .about-hero-lead {
  color: var(--color-muted);
  font-size: 15px;
  line-height: 1.8;
  max-width: 780px;
  margin: 0 0 28px;
  border-left: 3px solid var(--color-accent);
  padding-left: 16px;
}

.page-about .about-hero-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-stat {
  flex: 1 1 calc(50% - 6px);
  min-width: 130px;
  background: rgba(17, 17, 17, 0.42);
  border: 1px solid var(--about-border);
  border-radius: 10px;
  padding: 14px 16px;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.page-about .about-stat:nth-child(5) {
  flex: 1 1 100%;
}

.page-about .about-stat-num {
  font-family: var(--font-mono);
  font-size: 28px;
  font-weight: 800;
  color: var(--color-text);
  line-height: 1.1;
}

.page-about .about-stat-label {
  font-size: 12px;
  color: var(--color-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

/* ===== 区块通用 ===== */
.page-about .section-head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin: 0 0 12px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--about-border);
}

.page-about .section-index {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 800;
  color: var(--color-accent);
  letter-spacing: 0.12em;
}

.page-about .section-title {
  font-family: var(--font-head);
  font-size: clamp(32px, 8vw, 56px);
  font-weight: 900;
  color: var(--color-text);
  line-height: 1.05;
  margin: 0;
}

.page-about .section-intro {
  color: var(--color-muted);
  font-size: 15px;
  line-height: 1.75;
  max-width: 760px;
  margin: 0 0 28px;
  padding-left: 14px;
  border-left: 3px solid var(--color-accent);
}

/* ===== 01 收录范围 ===== */
.page-about .about-scope {
  padding: clamp(24px, 4vw, 40px) 0;
}

.page-about .scope-grid {
  display: grid;
  gap: 24px;
}

.page-about .scope-card {
  border: 3px solid var(--color-ink);
  border-radius: 14px;
  padding: 28px 24px;
  color: var(--color-ink);
  position: relative;
  box-shadow: 7px 7px 0 var(--color-ink);
  display: flex;
  flex-direction: column;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  overflow: hidden;
}

.page-about .scope-card:hover {
  transform: translate(-2px, -2px);
  box-shadow: 9px 9px 0 var(--color-ink);
}

.page-about .scope-card::after {
  content: '';
  position: absolute;
  right: 0;
  bottom: 0;
  width: 64px;
  height: 64px;
  background: repeating-linear-gradient(45deg, rgba(17, 17, 17, 0.16) 0 1px, transparent 1px 6px);
  pointer-events: none;
}

.page-about .scope-card--orange {
  background: var(--color-orange);
}

.page-about .scope-card--yellow {
  background: var(--color-yellow);
}

.page-about .scope-card--teal {
  background: var(--color-teal);
}

.page-about .scope-card-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.page-about .scope-card-num {
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 800;
  background: var(--color-ink);
  color: #fff;
  padding: 4px 10px;
  border-radius: 6px;
  letter-spacing: 0.08em;
}

.page-about .scope-card h3 {
  font-family: var(--font-head);
  font-size: 28px;
  font-weight: 900;
  margin: 4px 0 12px;
  letter-spacing: 0.02em;
}

.page-about .scope-card p {
  font-size: 14px;
  line-height: 1.75;
  margin: 0 0 16px;
  font-weight: 500;
}

.page-about .scope-sub-list {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: auto;
  padding: 0;
}

.page-about .scope-sub-list li {
  background: rgba(255, 255, 255, 0.35);
  border: 2px solid var(--color-ink);
  border-radius: 999px;
  padding: 4px 12px;
  font-size: 13px;
  font-weight: 700;
}

/* ===== 02 分类层级 ===== */
.page-about .about-hierarchy {
  margin: clamp(24px, 5vw, 48px) 0;
  padding: clamp(24px, 4vw, 40px);
  background: var(--color-band-purple);
  border: 3px solid var(--color-ink);
  border-radius: 16px;
  box-shadow: 8px 8px 0 rgba(17, 17, 17, 0.5);
}

.page-about .hierarchy-tree-wrap {
  background: rgba(0, 0, 0, 0.25);
  border: 2px solid var(--color-ink);
  border-radius: 12px;
  padding: clamp(12px, 3vw, 24px);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .hierarchy-tree {
  display: block;
  width: 100%;
  height: auto;
  min-width: 760px;
}

.page-about .hierarchy-tree .tree-links {
  stroke: rgba(255, 255, 255, 0.28);
  stroke-width: 2;
}

.page-about .hierarchy-tree .tree-root rect {
  fill: var(--color-accent);
  stroke: var(--color-ink);
  stroke-width: 2.5;
}

.page-about .hierarchy-tree .tree-root .tree-text-root {
  fill: var(--color-ink);
  font-size: 16px;
  font-weight: 900;
  font-family: var(--font-head);
}

.page-about .hierarchy-tree .tree-branch rect {
  stroke-width: 2.5;
}

.page-about .hierarchy-tree .tree-branch--local rect {
  fill: rgba(230, 126, 34, 0.18);
  stroke: var(--color-orange);
}

.page-about .hierarchy-tree .tree-branch--v3 rect {
  fill: rgba(241, 196, 15, 0.18);
  stroke: var(--color-yellow);
}

.page-about .hierarchy-tree .tree-branch--media rect {
  fill: rgba(26, 188, 156, 0.18);
  stroke: var(--color-teal);
}

.page-about .hierarchy-tree .tree-branch text {
  fill: var(--color-text);
  font-size: 18px;
  font-weight: 900;
  font-family: var(--font-head);
}

.page-about .hierarchy-tree .tree-leaf rect {
  fill: rgba(255, 255, 255, 0.06);
  stroke: rgba(255, 255, 255, 0.28);
  stroke-width: 1.5;
}

.page-about .hierarchy-tree .tree-leaf text {
  fill: var(--color-muted);
  font-size: 14px;
  font-weight: 600;
  font-family: var(--font-body);
}

.page-about .tree-details-group {
  display: grid;
  gap: 12px;
  margin-top: 16px;
}

.page-about .tree-details {
  background: rgba(0, 0, 0, 0.2);
  border: 2px solid var(--color-ink);
  border-radius: 10px;
  padding: 12px 16px;
}

.page-about .tree-details summary {
  cursor: pointer;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 15px;
  color: var(--color-text);
  list-style: none;
  display: flex;
  align-items: center;
  gap: 8px;
}

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

.page-about .tree-details summary::before {
  content: '+';
  font-family: var(--font-mono);
  font-weight: 800;
  color: var(--color-accent);
  font-size: 18px;
  line-height: 1;
}

.page-about .tree-details[open] summary::before {
  content: '–';
}

.page-about .tree-details ul {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 12px 0 0;
  padding: 10px 0 0;
  border-top: 1px solid var(--about-border);
  list-style: none;
}

.page-about .tree-details ul li {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid var(--about-border);
  border-radius: 999px;
  padding: 4px 12px;
  font-size: 13px;
  color: var(--color-muted);
}

.page-about .hierarchy-bottom {
  display: grid;
  gap: 24px;
  margin-top: 28px;
}

.page-about .tag-hierarchy {
  display: grid;
  gap: 12px;
}

.page-about .tag-tier {
  background: rgba(0, 0, 0, 0.2);
  border: 2px solid var(--color-ink);
  border-radius: 12px;
  padding: 18px 20px;
  border-left: 6px solid var(--color-accent);
}

.page-about .tag-tier-count {
  font-family: var(--font-mono);
  font-size: 30px;
  font-weight: 800;
  color: var(--color-accent);
  display: block;
  line-height: 1.1;
}

.page-about .tag-tier h3 {
  font-family: var(--font-head);
  font-size: 18px;
  color: var(--color-text);
  font-weight: 900;
  margin: 6px 0 8px;
}

.page-about .tag-tier p {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.75;
  margin: 0;
}

.page-about .hierarchy-figure img {
  width: 100%;
  max-width: 600px;
  height: auto;
  border: 2px solid var(--color-ink);
  border-radius: 12px;
  box-shadow: 6px 6px 0 rgba(17, 17, 17, 0.4);
  display: block;
}

.page-about .hierarchy-figure figcaption {
  color: var(--color-muted);
  font-size: 13px;
  margin-top: 10px;
  text-align: center;
}

/* ===== 03 版本演进 ===== */
.page-about .about-versions {
  padding: clamp(24px, 4vw, 40px) 0;
}

.page-about .version-image img {
  width: 100%;
  height: auto;
  max-width: 800px;
  border: 2px solid var(--color-ink);
  border-radius: 12px;
  box-shadow: 6px 6px 0 rgba(17, 17, 17, 0.4);
  display: block;
  margin: 0 auto;
}

.page-about .version-timeline {
  display: grid;
  gap: 24px;
  margin-top: 32px;
  position: relative;
}

.page-about .version-node {
  background: rgba(255, 255, 255, 0.05);
  border: 2px solid var(--color-ink);
  border-radius: 12px;
  padding: 22px 20px;
  position: relative;
  box-shadow: 4px 4px 0 rgba(17, 17, 17, 0.4);
}

.page-about .version-node::before {
  content: '';
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--color-accent);
  border: 3px solid var(--color-ink);
  position: absolute;
  top: -8px;
  left: 24px;
}

.page-about .version-tag {
  position: absolute;
  top: 14px;
  right: 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 999px;
  border: 2px solid var(--color-ink);
  background: #95A5A6;
  color: #111;
}

.page-about .version-node--new .version-tag {
  background: var(--color-accent);
}

.page-about .version-node--current .version-tag {
  background: var(--color-teal);
}

.page-about .version-node h3 {
  font-family: var(--font-mono);
  font-size: 28px;
  font-weight: 800;
  color: var(--color-text);
  margin: 0 0 10px;
}

.page-about .version-node p {
  color: var(--color-muted);
  font-size: 14px;
  line-height: 1.75;
  margin: 0 84px 0 0;
}

/* ===== 04 检索与筛选 ===== */
.page-about .about-search {
  margin: clamp(24px, 5vw, 48px) 0;
  padding: clamp(24px, 4vw, 40px);
  background: var(--color-band-dark);
  border: 3px solid var(--color-ink);
  border-radius: 16px;
  box-shadow: 8px 8px 0 rgba(17, 17, 17, 0.5);
}

.page-about .search-steps {
  display: grid;
  gap: 16px;
}

.page-about .search-step {
  background: rgba(255, 255, 255, 0.05);
  border: 2px solid var(--color-ink);
  border-radius: 12px;
  padding: 20px;
  display: grid;
  gap: 14px;
  align-content: start;
}

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

.page-about .search-step-num {
  font-family: var(--font-mono);
  font-size: 28px;
  font-weight: 800;
  color: var(--color-accent);
  line-height: 1;
}

.page-about .search-step-top h3 {
  font-family: var(--font-head);
  font-size: 18px;
  color: var(--color-text);
  margin: 0;
  font-weight: 900;
}

.page-about .search-step p {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.7;
  margin: 0;
}

/* UI 模拟 */
.page-about .ui-block {
  background: rgba(0, 0, 0, 0.35);
  border: 2px solid var(--color-ink);
  border-radius: 10px;
  padding: 10px;
  min-height: 96px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  justify-content: center;
}

.page-about .ui-window-bar {
  display: flex;
  gap: 4px;
  margin-bottom: 6px;
}

.page-about .ui-window-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.4);
}

.page-about .ui-window-dot:nth-child(1) {
  background: var(--color-rose);
}

.page-about .ui-window-dot:nth-child(2) {
  background: var(--color-yellow);
}

.page-about .ui-window-dot:nth-child(3) {
  background: var(--color-teal);
}

.page-about .ui-search-field {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: 6px;
  padding: 6px 8px;
  font-size: 12px;
  color: var(--color-text);
  font-family: var(--font-mono);
  width: 80%;
}

.page-about .ui-search-field::after {
  content: '|';
  color: var(--color-accent);
}

.page-about .ui-result-row {
  height: 8px;
  border-radius: 99px;
  background: rgba(255, 255, 255, 0.12);
  width: 100%;
}

.page-about .ui-result-row + .ui-result-row {
  width: 72%;
}

.page-about .ui-tab-row {
  display: flex;
  gap: 4px;
  margin-bottom: 8px;
  flex-wrap: wrap;
}

.page-about .ui-tab-pill {
  font-size: 10px;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: var(--color-muted);
  border-radius: 999px;
  padding: 3px 8px;
}

.page-about .ui-tab-pill.is-on {
  background: var(--color-orange);
  color: #111;
  border-color: var(--color-ink);
  font-weight: 700;
}

.page-about .ui-check-row {
  padding: 5px 8px;
  font-size: 12px;
  color: var(--color-muted);
  border-left: 2px solid rgba(255, 255, 255, 0.2);
  margin-bottom: 2px;
}

.page-about .ui-check-row::before {
  content: '▦';
  margin-right: 6px;
  color: var(--color-accent);
}

.page-about .ui-sort-opt {
  padding: 5px 8px;
  font-size: 12px;
  color: var(--color-muted);
  border-radius: 4px;
}

.page-about .ui-sort-opt.is-on {
  background: rgba(46, 204, 113, 0.15);
  color: var(--color-accent);
  font-family: var(--font-mono);
  border-left: 2px solid var(--color-accent);
}

.page-about .ui-tag-pill {
  display: inline-block;
  font-size: 10px;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.18);
  color: var(--color-muted);
  border-radius: 4px;
  padding: 3px 6px;
  margin: 2px;
}

.page-about .ui-tag-pill.is-lg {
  font-size: 13px;
  background: rgba(230, 126, 34, 0.25);
  color: var(--color-text);
  border-color: var(--color-orange);
}

.page-about .ui-alpha-row,
.page-about .ui-year-row {
  display: flex;
  flex-wrap: wrap;
  gap: 3px;
}

.page-about .ui-alpha-row span,
.page-about .ui-year-row span {
  font-family: var(--font-mono);
  font-size: 10px;
  padding: 2px 5px;
  border-radius: 3px;
  background: rgba(255, 255, 255, 0.06);
  color: var(--color-muted);
}

.page-about .ui-alpha-row span.is-on,
.page-about .ui-year-row span.is-on {
  background: var(--color-accent);
  color: #111;
  font-weight: 700;
}

.page-about .search-route {
  margin-top: 28px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.page-about .search-route img {
  width: 100%;
  max-width: 500px;
  height: auto;
  border: 2px solid var(--color-ink);
  border-radius: 12px;
  box-shadow: 6px 6px 0 rgba(17, 17, 17, 0.4);
}

/* ===== 05 更新机制 ===== */
.page-about .about-schedule {
  padding: clamp(24px, 4vw, 40px) 0;
}

.page-about .schedule-grid {
  display: grid;
  gap: 20px;
}

.page-about .schedule-block {
  border: 3px solid var(--color-ink);
  border-radius: 14px;
  padding: 24px;
  position: relative;
  overflow: hidden;
}

.page-about .schedule-block--daily {
  background: rgba(46, 204, 113, 0.12);
  border-left: 6px solid var(--color-accent);
}

.page-about .schedule-block--weekly {
  background: rgba(241, 196, 15, 0.12);
  border-left: 6px solid var(--color-yellow);
}

.page-about .schedule-block--format {
  background: rgba(52, 152, 219, 0.12);
  border-left: 6px solid var(--color-read);
}

.page-about .schedule-block h3 {
  font-family: var(--font-head);
  font-size: 20px;
  font-weight: 900;
  color: var(--color-text);
  margin: 0 0 10px;
}

.page-about .schedule-block p {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.7;
  margin: 0 0 18px;
}

.page-about .schedule-times,
.page-about .schedule-batches {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.page-about .schedule-times span,
.page-about .schedule-batches span {
  font-family: var(--font-mono);
  font-weight: 700;
  padding: 6px 14px;
  border-radius: 999px;
  border: 2px solid var(--color-ink);
  background: #111;
  color: var(--color-accent);
  font-size: 14px;
}

.page-about .schedule-code {
  font-family: var(--font-mono);
  font-size: 28px;
  font-weight: 800;
  background: #111;
  color: var(--color-accent);
  display: inline-block;
  border-radius: 10px;
  padding: 10px 18px;
  border: 2px solid var(--color-ink);
  letter-spacing: 0.06em;
}

.page-about .week-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
}

.page-about .week-day {
  flex: 1 1 calc(33.333% - 10px);
  min-width: 90px;
  background: rgba(255, 255, 255, 0.06);
  border: 2px solid var(--color-ink);
  border-radius: 10px;
  padding: 12px;
  text-align: center;
}

.page-about .week-day--batch {
  background: rgba(46, 204, 113, 0.12);
  border-color: var(--color-accent);
}

.page-about .week-day-name {
  display: block;
  font-family: var(--font-head);
  font-size: 17px;
  font-weight: 900;
  color: var(--color-text);
  margin-bottom: 6px;
}

.page-about .week-day-time {
  display: flex;
  justify-content: center;
  gap: 4px;
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--color-muted);
  flex-wrap: wrap;
}

.page-about .week-day-time span {
  background: rgba(255, 255, 255, 0.08);
  border-radius: 4px;
  padding: 2px 6px;
}

.page-about .week-day-badge {
  display: inline-block;
  margin-top: 6px;
  font-size: 10px;
  font-weight: 700;
  color: var(--color-ink);
  background: var(--color-accent);
  border-radius: 99px;
  padding: 2px 8px;
  border: 1px solid var(--color-ink);
}

.page-about .schedule-links {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 28px;
}

/* ===== 响应式增强 ===== */
@media (min-width: 720px) {
  .page-about .about-stat {
    flex: 1 1 auto;
  }

  .page-about .about-stat:nth-child(5) {
    flex: 1 1 auto;
  }

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

  .page-about .tree-details-group {
    grid-template-columns: repeat(3, 1fr);
  }

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

  .page-about .hierarchy-bottom {
    grid-template-columns: 1.2fr 0.8fr;
    align-items: start;
  }
}

@media (min-width: 900px) {
  .page-about .scope-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
  }

  .page-about .version-timeline {
    grid-template-columns: repeat(3, 1fr);
    gap: 0;
  }

  .page-about .version-timeline::before {
    content: '';
    position: absolute;
    top: 18px;
    left: 8%;
    right: 8%;
    height: 3px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 2px;
  }

  .page-about .version-node {
    margin: 0 10px;
  }

  .page-about .version-node::before {
    left: 50%;
    top: 10px;
    transform: translateX(-50%);
    width: 16px;
    height: 16px;
  }

  .page-about .version-tag {
    position: static;
    display: inline-block;
    margin-bottom: 10px;
  }

  .page-about .version-node p {
    margin: 0;
  }

  .page-about .schedule-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .page-about .week-day {
    flex: 1 1 0;
  }
}

@media (min-width: 1100px) {
  .page-about .search-steps {
    grid-template-columns: repeat(3, 1fr);
  }
}