.page-about {
  --about-dot: radial-gradient(circle, rgba(255, 255, 255, 0.07) 1px, transparent 1px);
  --about-dot-dark: radial-gradient(circle, rgba(26, 15, 46, 0.12) 1px, transparent 1px);
  --about-radius-lg: 24px;
  --about-radius-md: 16px;
  --about-gap: 18px;
  position: relative;
  color: var(--text-primary);
  font-family: var(--font-body);
}

.page-about .breadcrumb {
  max-width: 1280px;
  margin: 0 auto;
  padding: 28px 24px 0;
  color: var(--text-secondary);
  font-size: 14px;
}

.page-about .breadcrumb a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
}

.page-about .breadcrumb a:hover {
  text-shadow: 0 0 12px rgba(0, 207, 255, 0.55);
}

.page-about .breadcrumb__sep {
  margin: 0 10px;
  color: var(--border-subtle);
}

.page-about .breadcrumb__current {
  color: var(--card-b);
}

.page-about .about-section {
  max-width: 1280px;
  margin: 40px auto 0;
  border-radius: var(--about-radius-lg);
  padding: 30px 24px 36px;
  position: relative;
  border: 1px solid var(--border-subtle);
  box-shadow: 0 14px 36px rgba(0, 0, 0, 0.35);
}

.page-about .section-heading {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 22px;
}

.page-about .section-heading h2 {
  font-family: var(--font-display);
  font-size: clamp(26px, 4vw, 38px);
  letter-spacing: 0.5px;
  margin: 0;
  line-height: 1.2;
  text-transform: uppercase;
}

.page-about .heading-index {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  color: var(--accent);
  background: rgba(0, 207, 255, 0.12);
  border: 1px solid rgba(0, 207, 255, 0.4);
  border-radius: 999px;
  padding: 4px 12px;
  line-height: 1;
  min-width: 42px;
  text-align: center;
}

/* ===== 首屏 Hero ===== */
.page-about .about-hero {
  max-width: 1280px;
  margin: 26px auto 0;
  padding: 30px 24px 40px;
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
  background: linear-gradient(135deg, var(--bg-alt-1) 0%, var(--bg) 55%, var(--bg-alt-2) 100%);
  border: 1px solid var(--border-subtle);
  border-radius: var(--about-radius-lg);
  position: relative;
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: var(--about-dot);
  background-size: 18px 18px;
  pointer-events: none;
  opacity: 0.6;
}

.page-about .about-hero__left,
.page-about .about-hero__right {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__kicker {
  display: inline-block;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 2px;
  color: var(--card-b);
  border: 1px solid rgba(255, 210, 63, 0.5);
  border-radius: 999px;
  padding: 6px 14px;
  margin-bottom: 20px;
  background: rgba(255, 210, 63, 0.1);
}

.page-about .about-hero h1 {
  margin: 0 0 18px;
  font-size: clamp(28px, 4.6vw, 44px);
  font-family: var(--font-display);
  line-height: 1.25;
  letter-spacing: 1px;
  text-shadow: 0 0 30px rgba(0, 207, 255, 0.2);
  max-width: 680px;
}

.page-about .about-hero__lead {
  font-size: 16px;
  line-height: 1.75;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0;
}

.page-about .about-hero__right {
  display: flex;
  align-items: center;
  justify-content: center;
}

.page-about .about-hero__right img {
  width: 100%;
  max-width: 520px;
  height: auto;
  border-radius: 18px;
  object-fit: cover;
  border: 2px solid var(--border-subtle);
  box-shadow: 0 0 0 1px rgba(0, 207, 255, 0.2), 0 18px 48px rgba(0, 0, 0, 0.5);
}

/* ===== 01 本站定位 ===== */
.page-about .about-section--position {
  background: var(--bg-alt-1);
  background-image: var(--about-dot);
  background-size: 20px 20px;
}

.page-about .about-section--position .prose {
  font-size: 15px;
  line-height: 1.85;
  color: var(--text-primary);
  max-width: 920px;
}

.page-about .about-section--position .prose p {
  margin: 0 0 16px;
}

.page-about .position-badges {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin-top: 30px;
}

.page-about .position-badge {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 20px;
  border-radius: var(--about-radius-md);
  border: 2px solid transparent;
  position: relative;
  overflow: hidden;
}

.page-about .position-badge--a {
  background: var(--card-a);
  color: #1a0f2e;
  border-color: rgba(255, 255, 255, 0.45);
}

.page-about .position-badge--b {
  background: var(--card-b);
  color: #1a0f2e;
  border-color: rgba(255, 255, 255, 0.45);
}

.page-about .position-badge--c {
  background: var(--card-c);
  color: #1a0f2e;
  border-color: rgba(255, 255, 255, 0.45);
}

.page-about .position-badge__icon {
  position: absolute;
  right: 12px;
  top: 10px;
  font-size: 42px;
  opacity: 0.3;
  line-height: 1;
}

.page-about .position-badge strong {
  font-size: 14px;
  letter-spacing: 1px;
  text-transform: uppercase;
  opacity: 0.7;
}

.page-about .position-badge span:last-child {
  font-size: 18px;
  font-weight: 800;
}

/* ===== 02 收录范围与规模 ===== */
.page-about .about-section--stats {
  background: var(--bg-alt-2);
}

.page-about .stats-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--about-gap);
  margin-bottom: 22px;
}

.page-about .stat-card {
  padding: 24px 18px 26px;
  border-radius: var(--about-radius-md);
  display: flex;
  flex-direction: column;
  gap: 8px;
  position: relative;
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.3);
  border: 2px solid rgba(255, 255, 255, 0.4);
}

.page-about .stat-card--a {
  background: var(--card-a);
  color: #1a0f2e;
}

.page-about .stat-card--b {
  background: var(--card-b);
  color: #1a0f2e;
}

.page-about .stat-card--c {
  background: var(--card-c);
  color: #1a0f2e;
}

.page-about .stat-card--d {
  background: var(--card-d);
  color: #1a0f2e;
}

.page-about .stat-card__num {
  font-family: var(--font-mono);
  font-size: clamp(34px, 6vw, 52px);
  font-weight: 800;
  line-height: 1;
  letter-spacing: -1px;
}

.page-about .stat-card__label {
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.5px;
  opacity: 0.75;
}

.page-about .stats-note {
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-secondary);
  border-left: 4px solid var(--accent);
  background: rgba(0, 207, 255, 0.08);
  padding: 12px 16px;
  border-radius: 0 10px 10px 0;
  margin: 0;
}

/* ===== 03 分类与标签体系 ===== */
.page-about .about-section--taxonomy {
  background: var(--bg-light);
  color: var(--text-on-light);
  border-color: #d9c8f5;
}

.page-about .about-section--taxonomy .section-heading h2 {
  color: var(--text-on-light);
}

.page-about .about-section--taxonomy .heading-index {
  color: #fff;
  background: var(--text-on-light);
  border-color: var(--text-on-light);
}

.page-about .taxonomy-intro {
  font-size: 15px;
  line-height: 1.75;
  max-width: 720px;
  color: rgba(26, 15, 46, 0.75);
  margin: 0 0 28px;
}

.page-about .taxonomy-tree {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.page-about .taxonomy-branch {
  border-radius: var(--about-radius-md);
  overflow: hidden;
  background: rgba(255, 255, 255, 0.6);
  border: 2px solid rgba(26, 15, 46, 0.15);
  box-shadow: 0 8px 22px rgba(26, 15, 46, 0.08);
}

.page-about .taxonomy-branch__toggle {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 16px 18px;
  background: var(--text-on-light);
  border: none;
  cursor: pointer;
  color: #fff;
  font-family: var(--font-body);
  font-size: 15px;
  font-weight: 700;
  text-align: left;
}

.page-about .taxonomy-branch--shelf .taxonomy-branch__toggle {
  background: #2b1020;
}

.page-about .taxonomy-branch--genre .taxonomy-branch__toggle {
  background: #1a0f2e;
}

.page-about .taxonomy-branch--tag .taxonomy-branch__toggle {
  background: #0f0a1e;
}

.page-about .taxonomy-branch__label {
  flex: 1;
}

.page-about .taxonomy-branch__count {
  font-family: var(--font-mono);
  font-size: 14px;
  background: rgba(255, 255, 255, 0.2);
  border-radius: 999px;
  padding: 3px 10px;
  line-height: 1.4;
}

.page-about .taxonomy-branch__caret {
  font-size: 12px;
  color: var(--card-b);
}

.page-about .taxonomy-branch__content {
  padding: 18px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .shelf-block {
  display: inline-block;
  padding: 12px 18px;
  border-radius: 10px;
  font-weight: 800;
  font-size: 15px;
  color: #1a0f2e;
  border: 2px solid rgba(255, 255, 255, 0.5);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.12);
}

.page-about .shelf-block--a {
  background: var(--card-a);
}

.page-about .shelf-block--b {
  background: var(--card-b);
}

.page-about .shelf-block--c {
  background: var(--card-c);
}

.page-about .shelf-block--d {
  background: var(--card-d);
}

.page-about .genre-chip {
  display: inline-block;
  padding: 10px 16px;
  border-radius: 999px;
  font-weight: 700;
  font-size: 14px;
  color: #1a0f2e;
  border: 2px solid rgba(255, 255, 255, 0.5);
  box-shadow: 0 3px 10px rgba(0, 0, 0, 0.1);
}

.page-about .genre-chip[data-tone="a"] {
  background: var(--card-a);
}

.page-about .genre-chip[data-tone="b"] {
  background: var(--card-b);
}

.page-about .genre-chip[data-tone="c"] {
  background: var(--card-c);
}

.page-about .genre-chip[data-tone="d"] {
  background: var(--card-d);
}

.page-about .tag-chip {
  display: inline-block;
  padding: 7px 13px;
  border-radius: 8px;
  font-size: 13px;
  font-weight: 600;
  border: 1.5px solid rgba(26, 15, 46, 0.25);
  background: #fff;
  color: var(--text-on-light);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.page-about .tag-chip[data-tone="a"] {
  border-color: var(--card-a);
  color: #c33d0a;
}

.page-about .tag-chip[data-tone="b"] {
  border-color: #d9a800;
  color: #8a6d00;
}

.page-about .tag-chip[data-tone="c"] {
  border-color: var(--card-c);
  color: #008c66;
}

.page-about .tag-chip[data-tone="d"] {
  border-color: var(--card-d);
  color: #b42bbd;
}

.page-about .tag-chip:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

/* ===== 04 更新机制与批次 ===== */
.page-about .about-section--update {
  background: var(--bg-alt-1);
  background-image: linear-gradient(rgba(0, 207, 255, 0.04) 1px, transparent 1px);
  background-size: 100% 32px;
}

.page-about .update-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
}

.page-about .update-timeline {
  position: relative;
  padding-left: 30px;
}

.page-about .update-timeline::before {
  content: "";
  position: absolute;
  left: 0;
  top: 4px;
  bottom: 4px;
  width: 3px;
  border-radius: 3px;
  background: linear-gradient(180deg, var(--card-a), var(--accent), var(--card-c));
}

.page-about .timeline-item {
  position: relative;
  display: flex;
  gap: 16px;
  align-items: flex-start;
  margin-bottom: 20px;
}

.page-about .timeline-item:last-child {
  margin-bottom: 0;
}

.page-about .timeline-item__step {
  position: absolute;
  left: -30px;
  top: 0;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--accent);
  color: #1a0f2e;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 3px solid var(--bg-alt-1);
  box-shadow: 0 0 0 2px rgba(0, 207, 255, 0.5);
}

.page-about .timeline-item:nth-child(2) .timeline-item__step {
  background: var(--card-a);
}

.page-about .timeline-item:nth-child(3) .timeline-item__step {
  background: var(--card-b);
}

.page-about .timeline-item:nth-child(4) .timeline-item__step {
  background: var(--card-c);
}

.page-about .timeline-item:nth-child(5) .timeline-item__step {
  background: var(--card-d);
}

.page-about .timeline-item__body {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border-subtle);
  border-radius: 14px;
  padding: 16px 18px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  flex: 1;
}

.page-about .timeline-item__body strong {
  font-size: 16px;
  color: var(--text-primary);
  letter-spacing: 0.3px;
}

.page-about .timeline-item__body span {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.6;
}

.page-about .update-visual {
  display: flex;
  align-items: center;
  justify-content: center;
}

.page-about .update-visual img {
  width: 100%;
  max-width: 460px;
  height: auto;
  border-radius: 18px;
  border: 2px solid var(--border-subtle);
  object-fit: cover;
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.45);
}

/* ===== 05 版本与适配说明 ===== */
.page-about .about-section--version {
  background: var(--bg);
}

.page-about .version-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
}

.page-about .version-table-wrap {
  overflow-x: auto;
  border: 1px solid var(--border-subtle);
  border-radius: var(--about-radius-md);
  background: rgba(255, 255, 255, 0.04);
}

.page-about .table-compare {
  width: 100%;
  border-collapse: collapse;
  min-width: 420px;
}

.page-about .table-compare th,
.page-about .table-compare td {
  padding: 14px 18px;
  text-align: left;
  border-bottom: 1px solid var(--border-subtle);
  font-size: 14px;
  line-height: 1.6;
}

.page-about .table-compare th {
  background: var(--bg-alt-2);
  color: var(--card-b);
  font-family: var(--font-mono);
  letter-spacing: 1px;
  font-size: 13px;
  text-transform: uppercase;
}

.page-about .table-compare td:first-child {
  white-space: nowrap;
  color: var(--text-secondary);
  font-weight: 600;
  width: 140px;
}

.page-about .table-compare td:last-child {
  color: var(--text-primary);
  font-weight: 500;
}

.page-about .table-compare tr:last-child td {
  border-bottom: none;
}

.page-about .version-note {
  display: inline-block;
  margin-left: 10px;
  font-size: 13px;
  color: var(--text-secondary);
  background: rgba(255, 255, 255, 0.06);
  border-radius: 999px;
  padding: 2px 10px;
}

.page-about .version-visual {
  display: flex;
  align-items: center;
  justify-content: center;
}

.page-about .version-visual img {
  width: 100%;
  max-width: 280px;
  height: auto;
  border-radius: 18px;
  object-fit: cover;
  border: 2px solid var(--border-subtle);
  box-shadow: 0 0 0 1px rgba(0, 207, 255, 0.25), 0 16px 40px rgba(0, 0, 0, 0.5);
}

/* ===== 底部导航卡片 ===== */
.page-about .about-nav-grid {
  max-width: 1280px;
  margin: 40px auto 0;
  padding: 0 0 48px;
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
}

.page-about .nav-card {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 24px 22px;
  border-radius: var(--about-radius-md);
  text-decoration: none;
  color: #1a0f2e;
  font-family: var(--font-body);
  position: relative;
  overflow: hidden;
  border: 2px solid rgba(255, 255, 255, 0.5);
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.3);
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}

.page-about .nav-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 16px 36px rgba(0, 0, 0, 0.4);
}

.page-about .nav-card::after {
  content: "→";
  position: absolute;
  right: 18px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 24px;
  font-weight: 800;
  opacity: 0.5;
}

.page-about .nav-card--a {
  background: var(--card-a);
}

.page-about .nav-card--b {
  background: var(--card-b);
}

.page-about .nav-card--c {
  background: var(--card-c);
}

.page-about .nav-card strong {
  font-size: 20px;
  font-family: var(--font-display);
  letter-spacing: 0.5px;
}

.page-about .nav-card span {
  font-size: 14px;
  font-weight: 500;
  opacity: 0.75;
  max-width: 90%;
}

/* ===== 桌面端自适应 ===== */
@media (min-width: 768px) {
  .page-about .about-section {
    padding: 44px 48px 48px;
    margin-top: 50px;
  }

  .page-about .about-hero {
    grid-template-columns: 1.3fr 1fr;
    gap: 40px;
    padding: 44px 48px 48px;
    margin-top: 30px;
    align-items: center;
  }

  .page-about .about-hero__left {
    padding-right: 20px;
  }

  .page-about .about-hero__right img {
    max-width: 560px;
  }

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

  .page-about .position-badge {
    padding-bottom: 24px;
  }

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

  .page-about .stat-card {
    padding: 30px 22px 32px;
  }

  .page-about .taxonomy-branch__content {
    padding: 22px 24px;
    gap: 14px;
  }

  .page-about .update-layout {
    grid-template-columns: 1.4fr 1fr;
    gap: 36px;
    align-items: center;
  }

  .page-about .version-layout {
    grid-template-columns: 1.5fr 1fr;
    gap: 40px;
    align-items: start;
  }

  .page-about .about-nav-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    padding-bottom: 60px;
  }

  .page-about .nav-card {
    padding: 30px 26px 32px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-hero {
    margin-top: 36px;
  }

  .page-about .about-hero h1 {
    font-size: 46px;
  }

  .page-about .about-hero__lead {
    font-size: 17px;
  }

  .page-about .about-section--position .prose {
    font-size: 16px;
  }
}