.topic-hero {
  padding: clamp(3rem, 7vw, 6rem) 0;
  background: linear-gradient(135deg, var(--paper) 35%, #eef2ff);
  border-bottom: 1px solid var(--line);
}

.masthead nav [aria-current="page"] {
  color: var(--blue-dark);
  text-decoration: underline;
  text-underline-offset: 0.24em;
}

.topic-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
  align-items: center;
  gap: clamp(2rem, 6vw, 5rem);
}

.topic-hero-copy h1 {
  margin-block: 0.65rem 1rem;
  font-size: clamp(2.6rem, 7.4vw, 5.4rem);
  line-height: 1.12;
  letter-spacing: -0.055em;
}

.topic-intro {
  max-width: 31rem;
  color: var(--soft-ink);
  font-size: clamp(1rem, 2vw, 1.2rem);
}

.topic-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
  margin-top: 1.45rem;
}

.topic-signal-card {
  padding: clamp(1.25rem, 3.4vw, 2.3rem);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 1.25rem;
}

.topic-signal-path {
  display: grid;
  gap: 0.7rem;
  margin: 1rem 0;
  padding: 0;
  list-style: none;
}

.topic-signal-path li {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  padding: 0.7rem 0.9rem;
  background: #eef2ff;
  border-radius: 0.55rem;
}

.topic-signal-path li span {
  color: var(--blue-dark);
  font: 0.8rem var(--mono);
}

.topic-signal-card figcaption {
  color: var(--soft-ink);
  font-size: 0.9rem;
}

.topic-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.95rem;
}

.topic-panel {
  padding: clamp(1.1rem, 3vw, 1.8rem);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 1rem;
}

.topic-grid .topic-panel {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.55rem;
}

.topic-panel h3 {
  font-size: clamp(1.1rem, 2.4vw, 1.4rem);
  line-height: 1.35;
}

.topic-panel p,
.topic-findings dd,
.topic-next p {
  color: var(--soft-ink);
}

.topic-grid .topic-panel a {
  margin-top: auto;
  padding-top: 0.5rem;
  color: var(--blue-dark);
  font-weight: 650;
  text-decoration: underline;
  text-underline-offset: 0.18em;
}

.topic-evidence {
  background: #edf1fc;
  border-block: 1px solid var(--line);
}

.topic-evidence-card {
  max-width: 54rem;
}

.topic-card-top {
  display: grid;
  justify-items: start;
  gap: 0.6rem;
}

.topic-facts,
.topic-findings {
  display: grid;
  margin: 1.3rem 0;
}

.topic-facts {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.55rem;
}

.topic-facts div {
  padding: 0.7rem 0.85rem;
  background: #f4f6fd;
  border-radius: 0.55rem;
}

.topic-facts dt {
  color: var(--soft-ink);
  font-size: 0.82rem;
}

.topic-facts dd,
.topic-findings dd {
  margin-inline-start: 0;
}

.topic-facts dd,
.topic-findings dt {
  font-weight: 700;
}

.topic-findings {
  gap: 0.85rem;
}

.topic-findings div {
  padding-block-start: 0.85rem;
  border-top: 1px solid var(--line);
}

.topic-findings dd {
  margin-block-start: 0.25rem;
}

.topic-exercise {
  max-width: 54rem;
}

.topic-exercise ol {
  margin: 0 0 1rem;
  padding-inline-start: 1.5rem;
}

.topic-exercise li + li {
  margin-top: 0.4rem;
}

.topic-exercise details {
  padding-top: 0.85rem;
  border-top: 1px solid var(--line);
}

.topic-exercise summary {
  color: var(--blue-dark);
  font-weight: 700;
  cursor: pointer;
}

.topic-exercise details p {
  margin-top: 0.55rem;
}

.topic-next {
  padding-block: clamp(2rem, 5vw, 4rem);
  background: #eef2ff;
  border-top: 1px solid var(--line);
}

.topic-next-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1.2rem;
}

.topic-next-inner h2 {
  margin-block: 0.5rem 0.4rem;
  font-size: clamp(1.5rem, 3.8vw, 2.15rem);
  line-height: 1.3;
}

.topic-next-inner .topic-actions {
  margin-top: 0;
}

.topic-footer .back-top {
  grid-column: -2;
}

@media (max-width: 760px) {
  .topic-hero-grid,
  .topic-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 460px) {
  .topic-facts {
    grid-template-columns: 1fr;
  }
}