/* Quiz hub — chapter picker */
.quiz-chapter-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: clamp(16px, 3vw, 28px);
  width: 100%;
}

.quiz-chapter-grid--compact {
  grid-template-columns: repeat(auto-fill, minmax(210px, 1fr));
  gap: clamp(12px, 2vw, 18px);
}

@media (min-width: 900px) {
  .quiz-chapter-grid--compact {
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  }
}

.quiz-chapter-card {
  display: flex;
  flex-direction: column;
  min-height: min(320px, 50vh);
  padding: 0;
  border: 1.5px solid rgba(193, 198, 213, 0.45);
  border-radius: 1.25rem;
  background: #fff;
  box-shadow: 0 4px 24px rgba(0, 78, 159, 0.06);
  cursor: pointer;
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
  overflow: hidden;
  text-align: left;
}

.quiz-chapter-card--compact {
  min-height: 0;
  border-radius: 1rem;
}

.quiz-chapter-card:hover,
.quiz-chapter-card:focus-visible {
  transform: translateY(-2px);
  border-color: rgba(0, 78, 159, 0.35);
  box-shadow: 0 8px 32px rgba(0, 78, 159, 0.12);
  outline: none;
}

.quiz-chapter-card--ch2:hover,
.quiz-chapter-card--ch2:focus-visible {
  border-color: rgba(0, 109, 55, 0.4);
  box-shadow: 0 8px 32px rgba(0, 109, 55, 0.1);
}

.quiz-chapter-card--ch4:hover,
.quiz-chapter-card--ch4:focus-visible {
  border-color: rgba(0, 109, 55, 0.4);
  box-shadow: 0 8px 32px rgba(0, 109, 55, 0.1);
}

.quiz-chapter-card--ch5:hover,
.quiz-chapter-card--ch5:focus-visible {
  border-color: rgba(165, 0, 24, 0.35);
  box-shadow: 0 8px 32px rgba(165, 0, 24, 0.1);
}

.quiz-chapter-preview {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 160px;
  padding: 1.5rem;
}

.quiz-chapter-preview--ch2 {
  background: linear-gradient(145deg, #eefaf2 0%, #d8f0e0 50%, #f7f9fb 100%);
}

.quiz-chapter-preview--ch3 {
  background: linear-gradient(145deg, #eef6ff 0%, #dceeff 50%, #f7f9fb 100%);
}

.quiz-chapter-preview--ch4 {
  background: linear-gradient(145deg, #eefaf2 0%, #d8f0e0 50%, #f7f9fb 100%);
}

.quiz-chapter-preview--ch5 {
  background: linear-gradient(145deg, #fff0f2 0%, #ffd8de 50%, #f7f9fb 100%);
}

/* Photo preview — replaces gradient + icon */
.quiz-chapter-preview--photo {
  position: relative;
  flex: 0 0 auto;
  min-height: 0;
  padding: 0;
  aspect-ratio: 16 / 10;
  overflow: hidden;
  background: #e8ecf2;
}

.quiz-chapter-preview-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  display: block;
}

.quiz-chapter-preview-label {
  position: absolute;
  left: 10px;
  bottom: 10px;
  z-index: 1;
  padding: 4px 10px;
  border-radius: 8px;
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.02em;
  background: rgba(255, 255, 255, 0.92);
  border: 1px solid rgba(0, 0, 0, 0.06);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.quiz-chapter-preview-label--ch2 { color: #006d37; }
.quiz-chapter-preview-label--ch3 { color: #004e9f; }
.quiz-chapter-preview-label--ch4 { color: #006d37; }
.quiz-chapter-preview-label--ch5 { color: #a50018; }

.quiz-chapter-card--compact .quiz-chapter-info {
  padding: 0.85rem 1rem 1rem;
}

.quiz-chapter-card--compact .quiz-chapter-name {
  font-size: 1rem;
}

.quiz-chapter-card--compact .quiz-chapter-desc {
  font-size: 0.8rem;
  margin-bottom: 0.55rem;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.bio-slides-hub .chem-tools-title,
.bio-notes-hub .chem-tools-title,
.bio-quiz-hub .chem-tools-title,
.bio-flashcards-hub .chem-tools-title,
.bio-tools-hub .chem-tools-title {
  font-size: clamp(1.35rem, 3vh, 1.85rem);
  margin-bottom: clamp(4px, 0.8vh, 8px);
}

.bio-slides-hub .chem-tools-subtitle,
.bio-notes-hub .chem-tools-subtitle,
.bio-quiz-hub .chem-tools-subtitle,
.bio-flashcards-hub .chem-tools-subtitle,
.bio-tools-hub .chem-tools-subtitle {
  margin-bottom: clamp(12px, 2vh, 20px);
  font-size: clamp(0.78rem, 1.4vh, 0.9rem);
}

/* Interactive tools hub — same bordered cards as other tabs */
.bio-tools-hub .quiz-chapter-card--tool-ch3 .quiz-chapter-cta { color: #004e9f; }
.bio-tools-hub .quiz-chapter-card--tool-ch4 .quiz-chapter-cta { color: #006d37; }
.bio-tools-hub .quiz-chapter-card--tool-ch5 .quiz-chapter-cta { color: #a50018; }
.bio-tools-hub .quiz-chapter-card--tool-ch2 .quiz-chapter-cta { color: #006d37; }

.bio-tools-hub .quiz-chapter-card--tool-ch3:hover,
.bio-tools-hub .quiz-chapter-card--tool-ch3:focus-visible {
  border-color: rgba(0, 78, 159, 0.35);
  box-shadow: 0 8px 32px rgba(0, 78, 159, 0.12);
}

.bio-tools-hub .quiz-chapter-card--tool-ch4:hover,
.bio-tools-hub .quiz-chapter-card--tool-ch4:focus-visible,
.bio-tools-hub .quiz-chapter-card--tool-ch2:hover,
.bio-tools-hub .quiz-chapter-card--tool-ch2:focus-visible {
  border-color: rgba(0, 109, 55, 0.4);
  box-shadow: 0 8px 32px rgba(0, 109, 55, 0.1);
}

.bio-tools-hub .quiz-chapter-card--tool-ch5:hover,
.bio-tools-hub .quiz-chapter-card--tool-ch5:focus-visible {
  border-color: rgba(165, 0, 24, 0.35);
  box-shadow: 0 8px 32px rgba(165, 0, 24, 0.1);
}

.quiz-chapter-icon {
  width: 4.5rem;
  height: 4.5rem;
  border-radius: 1.25rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.quiz-chapter-icon--ch2 {
  background: rgba(0, 109, 55, 0.14);
  color: #006d37;
}

.quiz-chapter-icon--ch3 {
  background: rgba(0, 78, 159, 0.14);
  color: #004e9f;
}

.quiz-chapter-icon--ch4 {
  background: rgba(0, 109, 55, 0.14);
  color: #006d37;
}

.quiz-chapter-icon--ch5 {
  background: rgba(165, 0, 24, 0.12);
  color: #a50018;
}

.quiz-chapter-info {
  padding: 1.25rem 1.5rem 1.5rem;
  border-top: 1px solid rgba(193, 198, 213, 0.25);
}

.quiz-chapter-name {
  margin: 0 0 0.35rem;
  font-size: 1.15rem;
  font-weight: 700;
  color: #191c1e;
}

.quiz-chapter-desc {
  margin: 0 0 0.75rem;
  font-size: 0.875rem;
  line-height: 1.45;
  color: #414753;
}

.quiz-chapter-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
}

.quiz-chapter-badge {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  background: rgba(0, 78, 159, 0.1);
  color: #004e9f;
}

.quiz-chapter-badge--ch2 {
  background: rgba(0, 109, 55, 0.1);
  color: #006d37;
}

.quiz-chapter-badge--ch4 {
  background: rgba(0, 109, 55, 0.12);
  color: #006d37;
}

.quiz-chapter-badge--ch5 {
  background: rgba(165, 0, 24, 0.1);
  color: #a50018;
}

.quiz-chapter-cta {
  font-size: 0.875rem;
  font-weight: 700;
  color: #004e9f;
}

.quiz-chapter-card--ch4 .quiz-chapter-cta {
  color: #006d37;
}

.quiz-chapter-card--ch5 .quiz-chapter-cta {
  color: #a50018;
}

html.bio-embed .quiz-chapter-card {
  min-height: min(280px, 45vh);
}