/* Neft Math Brain UI — additive, scoped under .nb- classes. */
.nb-head {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  margin: 0 0 0.6rem;
}
.nb-head .nb-sub {
  font-size: 0.85rem;
  opacity: 0.7;
}
.nb-loading,
.nb-empty {
  opacity: 0.7;
  font-style: italic;
}

.nb-reclist {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 0.75rem;
}
.nb-rec {
  display: grid;
  gap: 0.25rem;
  padding: 0.85rem 1rem;
  border-radius: 12px;
  text-decoration: none;
  color: inherit;
  background: var(--nb-card-bg, #fff);
  border: 1px solid rgba(0, 0, 0, 0.1);
  border-left: 6px solid var(--nb-accent, #4f6ef7);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
  transition:
    transform 0.12s ease,
    box-shadow 0.12s ease;
}
.nb-rec:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.14);
}
.nb-rec-title {
  font-weight: 600;
}
.nb-rec-std {
  font-size: 0.72rem;
  letter-spacing: 0.03em;
  opacity: 0.65;
  text-transform: uppercase;
}
.nb-rec-why {
  font-size: 0.85rem;
  opacity: 0.85;
}
.nb-l0 {
  --nb-accent: #d9534f;
} /* most-supported */
.nb-l1 {
  --nb-accent: #4f6ef7;
} /* on-level */
.nb-l2 {
  --nb-accent: #2e9e5b;
} /* enrichment */

.nb-heatmap {
  border-collapse: collapse;
  font-size: 0.8rem;
  width: 100%;
}
.nb-heatmap th,
.nb-heatmap td {
  border: 1px solid rgba(0, 0, 0, 0.08);
  padding: 0.3rem 0.4rem;
  text-align: center;
}
.nb-heatmap th {
  writing-mode: vertical-rl;
  transform: rotate(180deg);
  font-weight: 600;
  white-space: nowrap;
}
.nb-heatmap th:first-child {
  writing-mode: horizontal-tb;
  transform: none;
}
.nb-name {
  text-align: left;
  font-weight: 600;
  white-space: nowrap;
}
.nb-cell {
  color: #1a1a1a;
  font-variant-numeric: tabular-nums;
}
.nb-struggling {
  background: #f8c9c5;
}
.nb-developing {
  background: #fde9b0;
}
.nb-proficient {
  background: #bfe6c9;
}
.nb-none {
  background: repeating-linear-gradient(
    45deg,
    #f3f3f3,
    #f3f3f3 4px,
    #ececec 4px,
    #ececec 8px
  );
}

@media (prefers-color-scheme: dark) {
  .nb-rec {
    --nb-card-bg: #1e2230;
    border-color: rgba(255, 255, 255, 0.12);
  }
  .nb-cell {
    color: #0c0c0c;
  }
}