.page-topics {
  --topics-slant: 21deg;
  --topics-num-size: 60px;
  --topics-cell: 44px;
  background: var(--color-surface);
  color: var(--color-ink);
  overflow-x: clip;
}

.page-topics [id] {
  scroll-margin-top: var(--space-8);
}

/* ---------- 首屏：斜线对切 ---------- */

.page-topics .topics-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-bottom: var(--border-thick) solid var(--color-contrast-line);
}

.page-topics .topics-hero__split {
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

.page-topics .topics-hero__panel {
  position: absolute;
  inset: 0;
  display: block;
}

.page-topics .topics-hero__panel--primary {
  background: var(--color-primary);
  clip-path: polygon(0 0, 62% 0, 40% 100%, 0 100%);
}

.page-topics .topics-hero__panel--deep {
  background: var(--color-contrast-surface);
  clip-path: polygon(62% 0, 100% 0, 100% 100%, 40% 100%);
}

.page-topics .topics-hero__slant {
  position: absolute;
  left: 51%;
  top: 50%;
  width: 6px;
  height: 180%;
  background: var(--color-contrast-accent);
  transform: translate(-50%, -50%) rotate(var(--topics-slant));
}

.page-topics .topics-hero__texture {
  position: absolute;
  inset: 0;
  z-index: 1;
  margin: 0;
  opacity: 0.16;
  mix-blend-mode: screen;
  pointer-events: none;
}

.page-topics .topics-hero__texture img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.page-topics .topics-hero__inner {
  position: relative;
  z-index: 2;
  display: grid;
  gap: var(--space-6);
  padding-block: calc(var(--space-8) * 1.4) var(--space-8);
}

.page-topics .topics-hero__crumbs {
  margin: 0;
}

.page-topics .topics-hero__crumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
}

.page-topics .topics-hero__crumbs a {
  color: var(--color-contrast-ink);
  text-decoration: none;
  border-bottom: var(--border-thin) solid var(--color-contrast-line);
}

.page-topics .topics-hero__crumbs span[aria-current="page"] {
  color: var(--color-contrast-accent);
}

.page-topics .topics-hero__eyebrow {
  color: var(--color-contrast-accent);
  margin-bottom: var(--space-3);
}

.page-topics .topics-hero__title {
  margin: 0 0 var(--space-4);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-display);
  line-height: 0.96;
  letter-spacing: var(--tracking-heading);
  color: var(--color-primary-ink);
}

.page-topics .topics-hero__lead {
  margin: 0;
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-contrast-ink);
}

.page-topics .topics-hero__figures {
  margin: 0;
  display: grid;
  gap: 0;
  border-top: var(--border-thick) solid var(--color-contrast-accent);
  padding-top: var(--space-2);
}

.page-topics .topics-hero__figures > div {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: baseline;
  gap: var(--space-3);
  padding-block: var(--space-3);
  border-bottom: var(--border-thick) solid var(--color-contrast-line);
}

.page-topics .topics-hero__figures dt {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-contrast-ink);
  opacity: 0.75;
}

.page-topics .topics-hero__figures dd {
  margin: 0;
  font-family: var(--font-mono);
  font-weight: var(--weight-heading);
  font-size: var(--text-2xl);
  line-height: 1;
  color: var(--color-contrast-accent);
  font-variant-numeric: tabular-nums;
}

/* ---------- 区块骨架 ---------- */

.page-topics .topics-section {
  padding-block: var(--section-y);
  border-bottom: var(--border-thick) solid var(--color-line);
}

.page-topics .topics-section--alt {
  background: var(--color-surface-alt);
}

.page-topics .topics-head {
  display: grid;
  gap: var(--space-3);
  margin-bottom: var(--space-6);
  border-top: var(--border-thick) solid var(--color-ink);
  padding-top: var(--space-3);
}

.page-topics .topics-head__title {
  margin: var(--space-2) 0 var(--space-3);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xl);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
}

.page-topics .topics-head__note {
  margin: 0;
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

.page-topics .topics-num {
  display: grid;
  place-items: center;
  width: var(--topics-num-size);
  height: var(--topics-num-size);
  border-radius: var(--radius-md);
  background: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-mono);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
}

.page-topics .topics-num--square {
  border-radius: 0;
  background: var(--color-accent);
}

.page-topics .topics-num--half {
  border-radius: var(--radius-md) var(--radius-md) 0 0;
  background: var(--color-contrast-surface);
  color: var(--color-contrast-accent);
}

.page-topics .topics-num--outline {
  background: transparent;
  border: var(--border-thick) solid var(--color-ink);
  color: var(--color-ink);
}

/* ---------- 专题一：案例列表 ---------- */

.page-topics .topics-cases__figure {
  margin: 0 0 var(--space-6);
}

.page-topics .topics-cases__figure .figure__media img,
.page-topics .topics-diff__figure .figure__media img,
.page-topics .topics-review__figure .figure__media img,
.page-topics .topics-index__figure .figure__media img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-topics .topics-cases__figure .figure__media,
.page-topics .topics-diff__figure .figure__media,
.page-topics .topics-review__figure .figure__media,
.page-topics .topics-index__figure .figure__media {
  border-radius: 0;
  overflow: hidden;
  border: var(--border-thick) solid var(--color-ink);
}

.page-topics .case-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-topics .case {
  border-top: var(--border-thick) solid var(--color-line);
}

.page-topics .case:last-child {
  border-bottom: var(--border-thick) solid var(--color-line);
}

.page-topics .case__head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: center;
  gap: var(--space-2) var(--space-3);
  padding-block: var(--space-3);
  cursor: pointer;
  list-style: none;
}

.page-topics .case__head::-webkit-details-marker {
  display: none;
}

.page-topics .case__head::marker {
  content: "";
}

.page-topics .case__head:hover .case__title {
  color: var(--color-primary);
}

.page-topics .case__head:focus-visible {
  outline: var(--border-thick) solid var(--color-focus);
  outline-offset: 4px;
}

.page-topics .case__num {
  display: grid;
  place-items: center;
  width: var(--topics-cell);
  height: var(--topics-cell);
  border-radius: var(--radius-md);
  background: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-mono);
  font-weight: var(--weight-heading);
  font-size: var(--text-sm);
}

.page-topics .case__title {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
  transition: color 120ms linear;
}

.page-topics .case__state {
  grid-column: 2;
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  justify-self: start;
}

.page-topics .case__toggle {
  position: relative;
  width: 16px;
  height: 16px;
  flex: none;
}

.page-topics .case__toggle::before,
.page-topics .case__toggle::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  height: 2px;
  background: var(--color-primary);
  transform: translateY(-50%);
}

.page-topics .case__toggle::after {
  transform: translateY(-50%) rotate(90deg);
  transition: transform 130ms linear;
}

.page-topics .case[open] .case__toggle::after {
  transform: translateY(-50%) rotate(0deg);
}

.page-topics .case__fields {
  margin: 0;
  padding: 0 0 var(--space-4);
  display: grid;
  gap: var(--space-3);
}

.page-topics .case__fields > div {
  display: grid;
  gap: var(--space-1);
}

.page-topics .case__fields dt {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  color: var(--color-ink-muted);
}

.page-topics .case__fields dd {
  margin: 0;
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

/* ---------- 专题二：对照表 ---------- */

.page-topics .topics-diff .filter-bar {
  margin-bottom: var(--space-4);
}

.page-topics .topics-diff__scroll {
  overflow-x: auto;
  border-top: var(--border-thick) solid var(--color-ink);
}

.page-topics .topics-diff__table {
  width: 100%;
  min-width: 720px;
  border-collapse: collapse;
  font-size: var(--text-base);
  background: transparent;
}

.page-topics .topics-diff__table caption {
  caption-side: top;
  text-align: left;
  padding: var(--space-2) 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
}

.page-topics .topics-diff__table th,
.page-topics .topics-diff__table td {
  text-align: left;
  padding: var(--space-2) var(--space-3) var(--space-2) 0;
  vertical-align: top;
  font-weight: var(--weight-body);
  color: var(--color-ink-soft);
}

.page-topics .topics-diff__table thead th {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
  border-bottom: var(--border-thick) solid var(--color-ink);
  padding-bottom: var(--space-2);
}

.page-topics .topics-diff__table tbody tr {
  border-bottom: var(--border-thin) solid var(--color-line);
}

.page-topics .topics-diff__table tbody th[scope="row"] {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
  white-space: nowrap;
}

.page-topics .topics-diff__table tbody tr.is-group-end td {
  border-bottom: 4px double var(--color-ink);
  padding-bottom: var(--space-3);
}

.page-topics .topics-diff__figure {
  margin: var(--space-6) 0 0;
}

/* ---------- 专题三：阶段复盘 ---------- */

.page-topics .review-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--space-6);
}

.page-topics .review {
  display: grid;
  gap: var(--space-2);
  border-top: var(--border-thick) solid var(--color-line);
  padding-top: var(--space-4);
}

.page-topics .review__mark {
  width: 88px;
  height: 44px;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
  background: var(--color-primary);
}

.page-topics .review__mark--accent {
  background: var(--color-accent);
}

.page-topics .review__mark--deep {
  background: var(--color-contrast-surface);
}

.page-topics .review__mark--half {
  background: var(--color-highlight);
  border: var(--border-thick) solid var(--color-ink);
  border-bottom: 0;
}

.page-topics .review__stage {
  margin: var(--space-2) 0 0;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
}

.page-topics .review__lead {
  margin: 0;
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

.page-topics .review__points {
  margin: var(--space-2) 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: var(--space-1);
}

.page-topics .review__points li {
  display: grid;
  grid-template-columns: 10px minmax(0, 1fr);
  gap: var(--space-2);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

.page-topics .review__points li::before {
  content: "";
  width: 8px;
  height: 8px;
  margin-top: calc(var(--space-2) * 0.6);
  background: var(--color-accent);
}

.page-topics .review__meta {
  margin: var(--space-2) 0 0;
  padding-top: var(--space-2);
  border-top: var(--border-thin) solid var(--color-line);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
}

.page-topics .topics-review__figure {
  margin: var(--space-8) 0 0;
}

/* ---------- 专题四：索引与延伸 ---------- */

.page-topics .index-grid {
  display: grid;
  gap: var(--space-6);
}

.page-topics .index-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: var(--border-thick) solid var(--color-ink);
}

.page-topics .index-item {
  border-bottom: var(--border-thick) solid var(--color-line);
}

.page-topics .index-item__link {
  display: grid;
  grid-template-columns: 48px minmax(0, 1fr);
  gap: var(--space-1) var(--space-3);
  padding-block: var(--space-3);
  color: inherit;
  text-decoration: none;
}

.page-topics .index-item__num {
  grid-column: 1;
  grid-row: 1;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  color: var(--color-primary);
}

.page-topics .index-item__name {
  grid-column: 2;
  grid-row: 1;
  font-size: var(--text-base);
  line-height: var(--leading-heading);
  color: var(--color-ink);
}

.page-topics .index-item__tags {
  grid-column: 2;
  grid-row: 2;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
}

.page-topics .index-item__link:hover .index-item__name {
  color: var(--color-primary);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.page-topics .index-item__link:focus-visible {
  outline: var(--border-thick) solid var(--color-focus);
  outline-offset: 2px;
}

.page-topics .topics-index__figure {
  margin: 0;
}

.page-topics .topics-next {
  margin-top: var(--space-8);
  padding-top: var(--space-4);
  border-top: 4px double var(--color-ink);
  display: grid;
  gap: 0;
}

.page-topics .topics-next__item {
  display: grid;
  gap: var(--space-1);
  padding-block: var(--space-3);
  border-bottom: var(--border-thin) solid var(--color-line);
  color: inherit;
  text-decoration: none;
}

.page-topics .topics-next__item:hover {
  background: color-mix(in srgb, var(--color-primary) 6%, transparent);
}

.page-topics .topics-next__item:focus-visible {
  outline: var(--border-thick) solid var(--color-focus);
  outline-offset: 2px;
}

.page-topics .topics-next__zone {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-base);
  color: var(--color-ink);
}

.page-topics .topics-next__desc {
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

.page-topics .topics-meta {
  margin: var(--space-6) 0 0;
  padding-top: var(--space-2);
  border-top: var(--border-thin) solid var(--color-line);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
}

/* ---------- 响应式 ---------- */

@media (max-width: 899px) {
  .page-topics .topics-hero__panel--primary {
    clip-path: inset(0 0 54% 0);
  }

  .page-topics .topics-hero__panel--deep {
    clip-path: inset(46% 0 0 0);
  }

  .page-topics .topics-hero__slant {
    left: 50%;
    top: 46%;
    width: 140%;
    height: 6px;
    transform: translate(-50%, -50%) rotate(-4deg);
  }
}

@media (min-width: 760px) {
  .page-topics .topics-head {
    grid-template-columns: var(--topics-num-size) minmax(0, 1fr);
    gap: var(--space-4);
    align-items: start;
  }

  .page-topics .topics-head__title {
    font-size: var(--text-2xl);
  }

  .page-topics .case__head {
    grid-template-columns: auto minmax(0, 1fr) auto;
    gap: var(--space-3);
  }

  .page-topics .case__state {
    grid-column: 3;
    justify-self: end;
  }

  .page-topics .case__fields {
    padding-left: var(--space-8);
  }

  .page-topics .case__fields > div {
    grid-template-columns: 108px minmax(0, 1fr);
    gap: var(--space-3);
    align-items: baseline;
  }

  .page-topics .review-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--space-8) var(--space-6);
  }

  .page-topics .topics-next {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: var(--space-6);
  }
}

@media (min-width: 900px) {
  .page-topics .topics-hero__inner {
    grid-template-columns: minmax(0, 1.4fr) minmax(280px, 0.6fr);
    align-items: end;
    gap: var(--space-8);
    padding-block: calc(var(--space-8) * 2) var(--space-8);
  }

  .page-topics .topics-hero__crumbs {
    grid-column: 1 / -1;
  }

  .page-topics .topics-section {
    padding-block: var(--section-y-lg);
  }

  .page-topics .index-grid {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 0.65fr);
    gap: var(--space-8);
    align-items: start;
  }

  .page-topics .topics-next {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-topics .case__title,
  .page-topics .case__toggle::after {
    transition: none;
  }
}