.page-topics {
  --topics-scrim: linear-gradient(
    180deg,
    color-mix(in srgb, var(--color-contrast-surface) 0%, transparent) 0%,
    color-mix(in srgb, var(--color-contrast-surface) 70%, transparent) 55%,
    color-mix(in srgb, var(--color-contrast-surface) 92%, transparent) 100%
  );
  --topics-hairline: color-mix(in srgb, var(--color-accent) 32%, transparent);
  --topics-link-line: color-mix(in srgb, var(--color-primary) 48%, transparent);
  display: block;
}

.page-topics .breadcrumb {
  margin-block: var(--space-4) var(--space-3);
}

/* ---------- 首屏 ---------- */

.page-topics .topics-hero {
  padding-bottom: var(--space-8);
}

.page-topics .topics-cover {
  position: relative;
  margin: 0;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--color-surface-alt);
}

.page-topics .topics-cover img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.page-topics .topics-cover::after {
  content: "";
  position: absolute;
  inset: 42% 0 0 0;
  background: var(--topics-scrim);
  pointer-events: none;
}

.page-topics .topics-figures {
  position: absolute;
  inset: auto 0 0 0;
  z-index: 1;
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: var(--space-2) var(--space-4);
  padding: var(--space-3);
  margin: 0;
}

.page-topics .figure-cell {
  display: flex;
  align-items: baseline;
  gap: var(--space-1);
  min-width: 0;
}

.page-topics .figure-num {
  font-size: var(--text-2xl);
  font-weight: var(--weight-heading);
  line-height: 0.9;
  letter-spacing: -0.03em;
  color: var(--color-contrast-ink);
}

.page-topics .figure-label {
  font-size: var(--text-xs);
  color: color-mix(in srgb, var(--color-contrast-ink) 76%, transparent);
}

.page-topics .topics-hero-text {
  margin-top: var(--space-4);
}

.page-topics .topics-hero-copy .sec-eyebrow {
  margin: 0 0 var(--space-2);
  color: var(--color-primary);
}

.page-topics .topics-title {
  margin: 0;
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
  text-wrap: balance;
}

.page-topics .topics-lead {
  margin: var(--space-3) 0 0;
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
  max-width: var(--measure);
}

.page-topics .topics-hero-aside .fav-btn {
  margin-top: var(--space-3);
}

/* ---------- 错位专题入口 ---------- */

.page-topics .topics-hooks {
  margin-top: var(--space-6);
  display: grid;
  gap: var(--space-2);
}

.page-topics .hook-card {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: var(--space-3);
  background: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  color: var(--color-ink);
  text-decoration: none;
  transition: border-color 0.25s ease, box-shadow 0.25s ease;
}

.page-topics .hook-card:hover,
.page-topics .hook-card:focus-visible {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-1);
}

.page-topics .hook-num {
  font-size: var(--text-xl);
  line-height: 1;
  color: var(--color-primary);
}

.page-topics .hook-name {
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
}

.page-topics .hook-note {
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

/* ---------- 筛选 ---------- */

.page-topics .topics-index {
  padding-bottom: var(--section-y);
}

.page-topics .topics-filter {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  padding-top: var(--space-3);
  border-top: var(--border-thick) solid var(--color-line);
  position: relative;
}

.page-topics .topics-filter::before {
  content: "";
  position: absolute;
  top: 5px;
  left: 0;
  right: 0;
  height: var(--border-thin);
  background: var(--color-line);
}

.page-topics .topics-filter .filter-count {
  margin-left: auto;
}

.page-topics .filter-note {
  margin: var(--space-2) 0 0;
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

/* ---------- 分组 ---------- */

.page-topics .topic-group {
  padding-top: var(--section-y);
  scroll-margin-top: var(--space-8);
}

.page-topics .group-head {
  position: relative;
  padding-top: var(--space-4);
  border-top: var(--border-thick) solid var(--color-line);
  margin-bottom: var(--space-4);
}

.page-topics .group-head::before {
  content: "";
  position: absolute;
  top: 5px;
  left: 0;
  right: 0;
  height: var(--border-thin);
  background: var(--color-line);
}

.page-topics .group-head-row {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
}

.page-topics .group-num {
  color: var(--color-primary);
}

.page-topics .group-head .sec-sub {
  margin: var(--space-1) 0 0;
  color: var(--color-ink-soft);
  max-width: var(--measure);
}

.page-topics .group-figure {
  margin: 0 0 var(--space-4);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--color-surface-alt);
}

.page-topics .group-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 8 / 5;
  object-fit: cover;
}

/* ---------- 专题条目 ---------- */

.page-topics .topic-list {
  display: grid;
  gap: var(--space-3);
}

.page-topics .topic-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding: var(--space-3);
  background: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  transition: border-color 0.25s ease;
}

.page-topics .topic-card:hover {
  border-color: var(--color-primary);
}

.page-topics .topic-num {
  margin: 0;
  font-size: var(--text-sm);
  letter-spacing: 0.1em;
  color: var(--color-accent);
}

.page-topics .topic-title {
  margin: 0;
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  color: var(--color-ink);
}

.page-topics .topic-lead {
  margin: 0;
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
  max-width: var(--measure);
}

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

.page-topics .topic-points li {
  padding: var(--space-1) 0;
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-ink-soft);
  border-bottom: var(--border-thin) solid var(--topics-hairline);
}

.page-topics .topic-points li:first-child {
  border-top: var(--border-thin) solid var(--topics-hairline);
}

.page-topics .topic-foot {
  margin-top: auto;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1) var(--space-3);
  padding-top: var(--space-1);
}

.page-topics .topic-link {
  font-size: var(--text-sm);
  color: var(--color-primary);
  text-decoration: none;
  border-bottom: var(--border-thin) solid var(--topics-link-line);
  padding-bottom: 2px;
}

.page-topics .topic-link::after {
  content: "→";
  display: inline-block;
  margin-left: 4px;
  color: var(--color-accent);
  transition: transform 0.2s ease;
}

.page-topics .topic-link:hover::after,
.page-topics .topic-link:focus-visible::after {
  transform: translateX(3px);
}

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

/* ---------- 桌面布局 ---------- */

@media (min-width: 720px) {
  .page-topics .topics-figures {
    padding: var(--space-4);
  }

  .page-topics .figure-num {
    font-size: var(--text-figure);
  }

  .page-topics .topics-hooks {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: var(--space-3);
    padding-bottom: var(--space-6);
  }

  .page-topics .hook-card:nth-child(2) {
    transform: translateY(var(--space-3));
  }

  .page-topics .hook-card:nth-child(3) {
    transform: translateY(calc(var(--space-3) * 2));
  }

  .page-topics .topic-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 960px) {
  .page-topics .topics-hero-text {
    display: grid;
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
    gap: var(--space-6);
    align-items: end;
    margin-top: var(--space-6);
  }

  .page-topics .topics-hero-aside {
    padding-bottom: var(--space-1);
  }

  .page-topics .group-figure {
    width: 70%;
  }

  .page-topics .topic-group:nth-child(even) .group-figure {
    margin-left: 0;
    margin-right: auto;
  }

  .page-topics .topic-group:nth-child(odd) .group-figure {
    margin-left: auto;
    margin-right: 0;
  }
}
</style>