.page-topics-index {
  --ti-rail-width: 296px;
  --ti-rule-gap: var(--space-4);
  padding-bottom: var(--space-8);
}

/* ---------- 页头 ---------- */

.page-topics-index .ti-head {
  padding-top: var(--space-6);
  padding-bottom: var(--space-6);
}

.page-topics-index .ti-title {
  margin: var(--space-2) 0 var(--space-3);
  font-family: var(--font-heading);
  font-size: var(--text-2xl);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
  max-width: 22ch;
}

@media (min-width: 720px) {
  .page-topics-index .ti-title {
    font-size: var(--text-3xl);
  }
}

.page-topics-index .ti-lede {
  max-width: 62ch;
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

/* ---------- 编号段标尺 ---------- */

.page-topics-index .ti-scale {
  margin-top: var(--space-6);
  padding: var(--space-4) var(--space-3);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-lg);
  background:
    linear-gradient(135deg,
      color-mix(in srgb, var(--color-primary) 12%, transparent) 0%,
      color-mix(in srgb, var(--color-primary-soft) 60%, transparent) 42%,
      color-mix(in srgb, var(--color-highlight) 44%, transparent) 100%);
  box-shadow: var(--shadow-1);
}

.page-topics-index .ti-scale__row {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.page-topics-index .ti-scale__tag {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-primary);
  padding: 3px 10px;
  border-radius: var(--radius-pill);
  background: color-mix(in srgb, var(--color-primary-ink) 72%, transparent);
}

.page-topics-index .ti-scale__num {
  font-family: var(--font-mono);
  font-size: var(--text-xl);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--color-ink);
}

.page-topics-index .ti-scale__line {
  flex: 1 1 60px;
  min-width: 40px;
  height: 0;
  border-top: 2px dotted var(--color-primary);
  opacity: 0.6;
}

.page-topics-index .ti-scale__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-2) var(--space-3);
  margin: var(--space-4) 0 0;
  padding: 0;
  list-style: none;
}

@media (min-width: 640px) {
  .page-topics-index .ti-scale__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-topics-index .ti-scale__facts li {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding-left: var(--space-2);
  border-left: 2px solid color-mix(in srgb, var(--color-accent) 55%, transparent);
}

.page-topics-index .ti-scale__facts b {
  font-family: var(--font-mono);
  font-size: var(--text-xl);
  font-weight: 700;
  line-height: 1.1;
  color: var(--color-accent);
}

.page-topics-index .ti-scale__facts span {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
}

/* ---------- 双栏骨架 ---------- */

.page-topics-index .ti-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-6);
  align-items: start;
}

@media (min-width: 960px) {
  .page-topics-index .ti-layout {
    grid-template-columns: minmax(0, 1fr) var(--ti-rail-width);
    gap: var(--space-8);
  }
}

.page-topics-index .ti-main {
  min-width: 0;
}

/* ---------- 正文区块 ---------- */

.page-topics-index .ti-section {
  padding-top: var(--space-6);
}

.page-topics-index .ti-section + .ti-section {
  margin-top: var(--space-4);
  border-top: 1px dashed var(--color-line);
}

.page-topics-index .ti-prose {
  max-width: 68ch;
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink);
}

.page-topics-index .ti-prose p + p {
  margin-top: var(--space-3);
}

.page-topics-index .section-lede {
  max-width: 62ch;
  margin-bottom: var(--space-4);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

/* ---------- 规则列表 ---------- */

.page-topics-index .ti-rules {
  margin: var(--space-4) 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: var(--space-2);
  counter-reset: ti-rule;
}

.page-topics-index .ti-rule {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: var(--space-2);
  align-items: start;
  padding: var(--space-3);
  border-radius: var(--radius-md);
  background: var(--color-surface-alt);
  border-left: 3px solid var(--color-primary);
}

.page-topics-index .ti-rule__index {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: 0.08em;
  padding-top: 2px;
}

.page-topics-index .ti-rule__title {
  margin: 0 0 4px;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
}

.page-topics-index .ti-rule__body p {
  margin: 0;
  font-size: var(--text-sm);
  line-height: 1.7;
  color: var(--color-ink-soft);
}

/* ---------- 图片 ---------- */

.page-topics-index .ti-figure {
  margin-top: var(--space-6);
}

.page-topics-index .ti-figure .figure__media,
.page-topics-index .ti-figure .figure__frame {
  border-radius: var(--radius-lg);
}

.page-topics-index .ti-figure figcaption {
  margin-top: var(--space-2);
  font-size: var(--text-sm);
  line-height: 1.7;
  color: var(--color-ink-muted);
}

/* ---------- 六段索引条目 ---------- */

.page-topics-index .ti-entries {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-topics-index .ti-entry {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-2);
  padding: var(--space-4) 0;
  border-top: 1px dashed var(--color-line);
}

.page-topics-index .ti-entry:last-child {
  border-bottom: 1px dashed var(--color-line);
}

@media (min-width: 680px) {
  .page-topics-index .ti-entry {
    grid-template-columns: 148px minmax(0, 1fr);
    gap: var(--space-4);
  }
}

.page-topics-index .ti-entry__stamp {
  align-self: start;
  display: inline-block;
  padding: 6px 12px;
  border-radius: var(--radius-pill);
  background: color-mix(in srgb, var(--color-highlight) 72%, transparent);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-accent) 28%, transparent);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 700;
  letter-spacing: 0.04em;
  color: color-mix(in srgb, var(--color-accent) 82%, var(--color-ink));
  white-space: nowrap;
}

.page-topics-index .ti-entry__body {
  min-width: 0;
}

.page-topics-index .ti-entry__title {
  margin: 0 0 var(--space-2);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: 1.35;
  color: var(--color-ink);
}

.page-topics-index .ti-entry__desc {
  margin: 0 0 var(--space-2);
  max-width: 62ch;
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

.page-topics-index .ti-entry__sample {
  margin: 0 0 var(--space-3);
  padding: var(--space-2) var(--space-3);
  border-left: 3px solid var(--color-primary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  background: color-mix(in srgb, var(--color-primary-soft) 55%, transparent);
  font-size: var(--text-sm);
  line-height: 1.7;
  color: var(--color-ink);
}

.page-topics-index .ti-entry__sample-key {
  display: inline-block;
  margin-right: 6px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-primary);
}

.page-topics-index .ti-entry__fields {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1) var(--space-4);
  margin: 0;
  padding: var(--space-2) 0 0;
  border-top: 1px dotted var(--color-line);
}

.page-topics-index .ti-entry__fields > div {
  display: flex;
  align-items: baseline;
  gap: 6px;
}

.page-topics-index .ti-entry__fields dt {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.page-topics-index .ti-entry__fields dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-ink);
}

/* ---------- 核对步骤 ---------- */

.page-topics-index .ti-steps {
  margin: 0 0 var(--space-4);
  padding: 0;
  list-style: none;
  display: grid;
  gap: var(--space-2);
}

.page-topics-index .ti-step {
  display: grid;
  grid-template-columns: 76px minmax(0, 1fr);
  gap: var(--space-3);
  align-items: baseline;
  padding: var(--space-3) var(--space-3) var(--space-3) 0;
  border-bottom: 1px dotted var(--color-line);
}

.page-topics-index .ti-step__no {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  color: var(--color-accent);
  padding-top: 3px;
}

.page-topics-index .ti-step p {
  margin: 0;
  font-size: var(--text-base);
  line-height: 1.75;
  color: var(--color-ink);
}

/* ---------- 说明块 ---------- */

.page-topics-index .ti-callout {
  margin-top: var(--space-4);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-lg);
  background: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
}

.page-topics-index .ti-callout p {
  margin: 0;
  max-width: 66ch;
  font-size: var(--text-sm);
  line-height: 1.8;
  color: var(--color-ink-soft);
}

/* ---------- 相邻入口 ---------- */

.page-topics-index .ti-nearby {
  border-top: 1px dashed var(--color-line);
}

.page-topics-index .ti-nearby__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-2);
}

@media (min-width: 720px) {
  .page-topics-index .ti-nearby__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.page-topics-index .ti-nearby__item {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  border: var(--border-thin) solid var(--color-line);
  background: var(--color-surface);
  box-shadow: var(--shadow-1);
  text-decoration: none;
  transition: transform 240ms cubic-bezier(0.2, 0.7, 0.2, 1),
              box-shadow 240ms cubic-bezier(0.2, 0.7, 0.2, 1),
              border-color 240ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.page-topics-index .ti-nearby__item:hover,
.page-topics-index .ti-nearby__item:focus-visible {
  transform: translateY(-3px);
  box-shadow: var(--shadow-2);
  border-color: color-mix(in srgb, var(--color-primary) 45%, transparent);
}

.page-topics-index .ti-nearby__key {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.page-topics-index .ti-nearby__name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
}

.page-topics-index .ti-nearby__desc {
  font-size: var(--text-sm);
  line-height: 1.7;
  color: var(--color-ink-soft);
}

.page-topics-index .ti-nearby__item .link-arrow {
  margin-top: var(--space-1);
  font-family: var(--font-mono);
  color: var(--color-accent);
}

.page-topics-index .ti-backline {
  margin: var(--space-3) 0 0;
  font-size: var(--text-sm);
  line-height: 1.8;
  color: var(--color-ink-muted);
}

.page-topics-index .ti-inline-link {
  color: var(--color-accent);
  text-decoration: underline;
  text-decoration-style: dotted;
  text-underline-offset: 3px;
}

.page-topics-index .ti-inline-link:hover,
.page-topics-index .ti-inline-link:focus-visible {
  text-decoration-style: solid;
}

/* ---------- 侧栏速查 ---------- */

.page-topics-index .ti-rail {
  min-width: 0;
}

@media (min-width: 960px) {
  .page-topics-index .ti-rail__inner {
    position: sticky;
    top: 88px;
  }
}

.page-topics-index .ti-rail__inner {
  padding: var(--space-3);
  border-radius: var(--radius-lg);
  background: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
}

.page-topics-index .ti-rail__title {
  margin: 6px 0 var(--space-3);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
}

.page-topics-index .ti-lookup {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 2px;
}

.page-topics-index .ti-lookup__link {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  border-left: 3px solid transparent;
  text-decoration: none;
  transition: background-color 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              border-color 200ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.page-topics-index .ti-lookup__link:hover,
.page-topics-index .ti-lookup__link:focus-visible {
  background: color-mix(in srgb, var(--color-highlight) 70%, transparent);
  border-left-color: var(--color-accent);
}

.page-topics-index .ti-lookup__range {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 700;
  letter-spacing: 0.03em;
  color: var(--color-ink);
}

.page-topics-index .ti-lookup__cat {
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.page-topics-index .ti-rail__figure {
  margin: var(--space-3) 0 var(--space-2);
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: var(--border-thin) solid var(--color-line);
}

.page-topics-index .ti-rail__figure img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-topics-index .ti-rail__note {
  font-size: var(--text-xs);
  line-height: 1.8;
}

/* ---------- 图片通用约束 ---------- */

.page-topics-index .figure__frame img,
.page-topics-index .ti-rail__figure img {
  max-width: 100%;
  height: auto;
}

/* ---------- 动效降级 ---------- */

@media (prefers-reduced-motion: reduce) {
  .page-topics-index .ti-nearby__item,
  .page-topics-index .ti-lookup__link {
    transition: none;
  }
  .page-topics-index .ti-nearby__item:hover,
  .page-topics-index .ti-nearby__item:focus-visible {
    transform: none;
  }
}