/* Solar Inverters & Battery Storage EMF Lesson CSS */
#solar-lesson {
  margin-top: 1.5rem;
}

.lesson-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
  border-bottom: 1px solid var(--line);
  padding-bottom: 0.75rem;
}

.tab-btn {
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 0.5rem 0.9rem;
  border-radius: 6px;
  font-family: inherit;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--ink);
  cursor: pointer;
  transition: all 0.2s ease;
}

.tab-btn:hover {
  background: #e8ecf2;
}

.tab-btn.active {
  background: var(--blue);
  color: #fff;
  border-color: var(--blue);
}

.lesson-panel {
  display: none;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 1.75rem;
  margin-bottom: 1.5rem;
  box-shadow: 0 2px 8px rgba(21, 34, 57, 0.04);
}

.lesson-panel.active {
  display: block;
}

.lesson-panel h2 {
  font-size: 1.4rem;
  margin-top: 0;
  margin-bottom: 0.5rem;
  color: var(--ink);
}

.panel-subtitle {
  color: #556987;
  font-size: 0.95rem;
  margin-bottom: 1.5rem;
  line-height: 1.5;
}

/* Chapter 1: Solar Architecture Cards */
.solar-arch-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.solar-card {
  border: 2px solid var(--line);
  border-radius: 8px;
  padding: 1.25rem;
  background: var(--paper);
  cursor: pointer;
  transition: all 0.2s ease;
  text-align: left;
}

.solar-card:hover {
  border-color: #a0aec0;
}

.solar-card.active {
  border-color: var(--blue);
  background: #f0f5ff;
}

.solar-icon {
  font-size: 2rem;
  display: block;
  margin-bottom: 0.4rem;
}

.solar-card h3 {
  margin: 0.2rem 0 0.4rem 0;
  font-size: 1.05rem;
  color: var(--ink);
}

.solar-tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  background: #e2e8f0;
  color: #4a5568;
}

.solar-detail-box {
  background: #0b1320;
  border-radius: 8px;
  padding: 1.5rem;
  color: #fff;
  margin-bottom: 1.5rem;
}

.solar-stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}

.solar-stat-card {
  background: #152239;
  border: 1px solid #23395d;
  padding: 0.85rem;
  border-radius: 6px;
}

.readout-label {
  font-size: 0.75rem;
  color: #8da4c4;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.readout-value {
  font-size: 1.35rem;
  font-weight: 700;
  color: #a8f074;
  margin-top: 0.2rem;
}

/* Chapter 2: Oscilloscope Simulator */
.scope-container {
  background: #0b1320;
  border-radius: 8px;
  padding: 1.5rem;
  color: #fff;
  margin-bottom: 1.5rem;
}

.scope-screen {
  height: 160px;
  background: #070d17;
  border: 1px solid #1e3a5f;
  border-radius: 6px;
  position: relative;
  overflow: hidden;
  margin: 1rem 0;
}

.scope-grid-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-image: 
    linear-gradient(to right, rgba(30, 58, 95, 0.3) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(30, 58, 95, 0.3) 1px, transparent 1px);
  background-size: 25px 25px;
}

.scope-svg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

.solar-slider-row {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-top: 1rem;
}

/* Chapter 3: Filter Toggle */
.filter-compare-box {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}

.toggle-btn-group {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1.25rem;
}

.filter-toggle-btn {
  flex: 1;
  padding: 0.75rem 1rem;
  border: 2px solid var(--line);
  background: #fff;
  border-radius: 6px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.filter-toggle-btn.active {
  background: var(--blue);
  color: #fff;
  border-color: var(--blue);
}

.filter-results-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
}

/* Chapter 4: Placement */
.placement-diagram-box {
  background: #0f172a;
  border-radius: 8px;
  padding: 1.5rem;
  color: #fff;
  margin-bottom: 1.5rem;
}

.zone-selector {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.zone-btn {
  background: #1e293b;
  border: 1px solid #334155;
  color: #fff;
  padding: 0.75rem;
  border-radius: 6px;
  cursor: pointer;
  text-align: left;
  font-family: inherit;
  transition: all 0.2s;
}

.zone-btn:hover {
  background: #28374d;
}

.zone-btn.active {
  border-color: #a8f074;
  background: #172554;
}

/* Chapter 5: Quiz */
.quiz-item {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 1.25rem;
  margin-bottom: 1.25rem;
}

.quiz-question {
  font-weight: 600;
  font-size: 1rem;
  margin-bottom: 0.75rem;
  color: var(--ink);
}

.quiz-options {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.quiz-opt-btn {
  background: #fff;
  border: 1px solid var(--line);
  padding: 0.75rem 1rem;
  border-radius: 6px;
  text-align: left;
  font-family: inherit;
  font-size: 0.9rem;
  color: var(--ink);
  cursor: pointer;
  transition: all 0.2s ease;
}

.quiz-opt-btn:hover {
  background: #f1f5f9;
  border-color: #94a3b8;
}

.quiz-opt-btn.correct {
  background: #dcfce7;
  border-color: #16a34a;
  color: #15803d;
  font-weight: 600;
}

.quiz-opt-btn.incorrect {
  background: #fee2e2;
  border-color: #dc2626;
  color: #991b1b;
}

.quiz-feedback {
  margin-top: 0.75rem;
  padding: 0.75rem;
  border-radius: 6px;
  font-size: 0.88rem;
  line-height: 1.4;
  display: none;
}

.quiz-feedback.show {
  display: block;
}

.feedback-correct {
  background: #dcfce7;
  color: #166534;
}

.feedback-incorrect {
  background: #fee2e2;
  color: #991b1b;
}

/* Nav Controls */
.lesson-nav-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 2rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
}

.callout-box {
  background: #f8fafc;
  border-left: 4px solid var(--blue);
  padding: 1rem 1.25rem;
  border-radius: 0 6px 6px 0;
  margin: 1.25rem 0;
  font-size: 0.92rem;
}