/* ======== ELECTRONIC ENGINEER STYLES ======== */
/* Dark blue/cyan circuit board theme */

/* ---- ANIMATIONS ---- */
@keyframes elec-glow {
  0%, 100% { box-shadow: 0 0 4px rgba(56, 189, 248, 0.3); }
  50%      { box-shadow: 0 0 16px rgba(56, 189, 248, 0.7); }
}

@keyframes elec-blink {
  0%, 100% { opacity: 1; }
  50%      { opacity: 0.15; }
}

@keyframes elec-flow {
  0%   { background-position: 0% 50%; }
  100% { background-position: 200% 50%; }
}

@keyframes elec-fadeIn {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ---- HOME SCREEN ---- */
.elec-home {
  max-width: 700px;
  margin: 0 auto;
  padding-bottom: var(--space-8);
}

.elec-header {
  margin-bottom: var(--space-4);
}

.elec-home h1 {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  margin: var(--space-2) 0 var(--space-1);
}

/* Stats bar */
.elec-stats-bar {
  display: flex;
  gap: var(--space-3);
  flex-wrap: wrap;
  margin-bottom: var(--space-5);
}

.elec-stat-item {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  background: var(--color-surface-2);
  border-radius: var(--radius-full, 50px);
  font-size: var(--text-sm);
  font-weight: 600;
}

/* ---- SECTION HEADERS ---- */
.elec-section-title {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 700;
  margin: var(--space-5) 0 var(--space-3);
  padding-bottom: var(--space-2);
  border-bottom: 2px solid #38bdf8;
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

/* ---- LESSON BUTTONS ---- */
.elec-tier-group {
  margin-bottom: var(--space-3);
}
.elec-tier-label {
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: var(--space-2);
}
.elec-lesson-row {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: var(--space-2);
}
.elec-lesson-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: var(--space-3);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-lg, 16px);
  background: var(--color-surface, #fff);
  cursor: pointer;
  transition: all 0.2s;
  text-align: center;
}
.elec-lesson-btn:hover {
  border-color: #38bdf8;
  box-shadow: 0 0 8px rgba(56, 189, 248, 0.2);
  transform: translateY(-2px);
}
.elec-lesson-btn.completed {
  border-color: #22c55e;
  background: var(--feedback-completed-bg);
}
.elec-lesson-btn.locked {
  opacity: 0.45;
  cursor: not-allowed;
  filter: grayscale(0.5);
  background: #f1f5f9;
}
.elec-lesson-emoji {
  font-size: 1.8rem;
}
.elec-lesson-name {
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--color-text);
}
.elec-tier-badge {
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  color: #38bdf8;
  background: var(--color-surface-2);
  padding: 2px 8px;
  border-radius: 10px;
}
.elec-completed-badge {
  color: #22c55e;
  font-weight: bold;
  font-size: 1.1rem;
}
.elec-subtitle {
  color: var(--color-text-faint);
  margin-bottom: var(--space-4);
}

/* ---- CARD GRID ---- */
.elec-card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-4);
}

.elec-card,
.elec-activity-card {
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg, 16px);
  padding: var(--space-4) var(--space-5);
  cursor: pointer;
  transition: transform 0.15s, border-color 0.15s, box-shadow 0.15s;
  display: flex;
  align-items: flex-start;
  gap: var(--space-4);
  position: relative;
  overflow: hidden;
}

.elec-card:hover,
.elec-activity-card:hover:not(.locked) {
  transform: translateY(-3px);
  border-color: #38bdf8;
  box-shadow: 0 0 20px rgba(56, 189, 248, 0.25), 0 6px 20px rgba(0, 0, 0, 0.08);
}

.elec-activity-card.locked {
  opacity: 0.5;
  cursor: not-allowed;
}

.elec-lock-overlay {
  position: absolute;
  top: 8px;
  right: 12px;
  font-size: 1.2rem;
  background: rgba(0,0,0,0.6);
  color: #fff;
  border-radius: 8px;
  padding: 2px 8px;
  font-weight: 600;
}

.elec-card-emoji {
  font-size: 2.5rem;
  flex-shrink: 0;
  line-height: 1;
}

.elec-card-body {
  flex: 1;
  min-width: 0;
}

.elec-card-title {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 700;
  margin: 0 0 var(--space-1);
}

.elec-card-desc {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin: 0 0 var(--space-2);
}

.elec-card-progress {
  font-size: var(--text-xs);
  color: #38bdf8;
  font-weight: 600;
}

.elec-card-tier {
  display: inline-block;
  font-size: var(--text-xs);
  font-weight: 700;
  padding: 2px var(--space-2);
  border-radius: var(--radius-full, 50px);
  background: rgba(56, 189, 248, 0.15);
  color: #38bdf8;
  margin-top: var(--space-1);
}

/* ---- LESSON VIEWER ---- */
.elec-lesson-wrap {
  max-width: 600px;
  margin: 0 auto;
  padding-bottom: var(--space-8);
  animation: elec-fadeIn 0.35s ease;
}

.elec-lesson-card {
  background: #1e293b;
  border: 2px solid #334155;
  border-radius: var(--radius-lg, 16px);
  padding: var(--space-5);
  margin-bottom: var(--space-4);
  color: #f1f5f9;
  box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}

.elec-lesson-heading {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 700;
  margin: 0 0 var(--space-3);
  color: #38bdf8;
}

.elec-lesson-body {
  font-size: var(--text-base);
  line-height: 1.7;
  color: #e2e8f0;
}
.elec-lesson-body strong {
  color: #38bdf8;
}

.elec-lesson-visual {
  text-align: center;
  margin: var(--space-4) 0;
  line-height: 1;
  padding: var(--space-4);
  background: #0f172a;
  border-radius: 12px;
  border: 1px solid #334155;
}

.elec-lesson-nav,
.elec-nav-buttons {
  display: flex;
  gap: var(--space-3);
  justify-content: space-between;
  margin-top: var(--space-4);
}
.elec-lesson-nav .elec-btn,
.elec-nav-buttons .elec-btn {
  flex: 1;
  text-align: center;
}
.elec-lesson-nav .elec-btn.primary,
.elec-nav-buttons .elec-btn.primary {
  background: #38bdf8;
  border-color: #38bdf8;
}
.elec-lesson-nav .elec-btn:disabled,
.elec-nav-buttons .elec-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

/* Lesson page counter */
.elec-page-counter {
  color: var(--color-text-faint);
  font-size: 0.85rem;
  margin-bottom: var(--space-2);
}

/* Lesson title in dark theme */
.elec-lesson-wrap h2 {
  color: var(--color-text);
  font-family: var(--font-display);
}

.elec-lesson-nav button {
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-full, 50px);
  font-weight: 700;
  font-size: var(--text-base);
  cursor: pointer;
  border: 2px solid var(--color-border);
  background: var(--color-surface);
  font-family: inherit;
  transition: all 0.15s;
}

.elec-lesson-nav button:hover { transform: translateY(-1px); }
.elec-lesson-nav button:disabled { opacity: 0.4; cursor: default; }

.elec-lesson-nav button.primary {
  background: #38bdf8;
  color: #fff;
  border-color: #38bdf8;
}

/* Lesson progress pips */
.elec-lesson-progress {
  display: flex;
  justify-content: center;
  gap: var(--space-2);
  margin-bottom: var(--space-3);
}

.elec-lesson-progress span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--color-surface-2);
  transition: background 0.2s;
}

.elec-lesson-progress span.active {
  background: #38bdf8;
}

.elec-lesson-progress span.done {
  background: #22c55e;
}

/* ---- QUIZ ---- */
.elec-quiz-box,
.elec-question-card {
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg, 16px);
  padding: var(--space-5);
  margin-bottom: var(--space-4);
}

.elec-quiz-question,
.elec-q-prompt {
  font-size: var(--text-lg);
  font-weight: 600;
  text-align: center;
  margin-bottom: var(--space-4);
}

.elec-q-badge {
  display: inline-block;
  background: var(--color-surface-2);
  color: #0284c7;
  font-weight: 700;
  font-size: 0.8rem;
  padding: 4px 12px;
  border-radius: 10px;
  margin-bottom: var(--space-3);
}

.elec-quiz-opts,
.elec-options {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.elec-quiz-opt,
.elec-option-btn {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md, 12px);
  font-size: var(--text-base);
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s;
  font-family: inherit;
  text-align: left;
  width: 100%;
}

.elec-quiz-opt:hover:not(:disabled),
.elec-option-btn:hover:not(:disabled) {
  border-color: #38bdf8;
  background: rgba(56, 189, 248, 0.08);
}

.elec-quiz-opt.correct,
.elec-option-btn.correct {
  border-color: #22c55e !important;
  background: var(--feedback-correct-bg) !important;
  color: var(--feedback-correct-text);
}

.elec-quiz-opt.wrong,
.elec-option-btn.wrong {
  border-color: #ef4444 !important;
  background: var(--feedback-wrong-bg) !important;
  color: #991b1b;
}

.elec-quiz-opt:disabled,
.elec-option-btn:disabled { cursor: default; opacity: 0.7; }

.elec-opt-letter {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--color-surface-2);
  color: #0284c7;
  font-weight: 700;
  font-size: 0.8rem;
  flex-shrink: 0;
}

.elec-progress-bar {
  flex: 1;
  height: 8px;
  background: var(--color-border);
  border-radius: 4px;
  overflow: hidden;
}
.elec-progress-fill {
  height: 100%;
  background: #38bdf8;
  border-radius: 4px;
  transition: width 0.3s;
}
.elec-score-display {
  font-weight: 700;
  color: #38bdf8;
  font-size: 0.9rem;
}
.elec-activity-screen {
  max-width: 600px;
  margin: 0 auto;
  padding-bottom: var(--space-8);
}
.elec-activity-top {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
}
.elec-activity-title {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  margin: 0;
}
.elec-study-counter {
  color: var(--color-text-faint);
  font-size: 0.85rem;
  margin-bottom: var(--space-2);
}

.elec-quiz-explain,
.elec-explain-box {
  margin-top: var(--space-4);
  padding: var(--space-4);
  border-radius: var(--radius-md, 12px);
  background: rgba(56, 189, 248, 0.08);
  border: 1px solid rgba(56, 189, 248, 0.2);
  font-size: var(--text-sm);
  line-height: 1.6;
}

.elec-quiz-next {
  margin-top: var(--space-4);
  padding: var(--space-3) var(--space-6);
  background: #38bdf8;
  color: #fff;
  border: none;
  border-radius: var(--radius-full, 50px);
  font-weight: 700;
  font-size: var(--text-base);
  cursor: pointer;
  font-family: inherit;
  display: block;
  margin-left: auto;
  margin-right: auto;
  transition: background 0.15s;
}

.elec-quiz-next:hover { filter: brightness(1.1); }

.elec-quiz-result {
  text-align: center;
  padding: var(--space-6);
}

.elec-quiz-result h2 {
  font-family: var(--font-display);
  margin: 0 0 var(--space-2);
}

/* ---- CIRCUIT BUILDER (Beginner Lab) ---- */
.elec-circuit-wrap {
  max-width: 600px;
  margin: 0 auto;
  padding-bottom: var(--space-8);
}

.elec-circuit-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(60px, 1fr));
  gap: 4px;
  margin-bottom: var(--space-4);
  padding: var(--space-3);
  background: #1e293b;
  border-radius: var(--radius-lg, 16px);
  border: 2px solid rgba(56, 189, 248, 0.2);
}

.elec-circuit-cell {
  width: 100%;
  aspect-ratio: 1;
  min-height: 60px;
  background: rgba(56, 189, 248, 0.05);
  border: 1px dashed rgba(56, 189, 248, 0.2);
  border-radius: var(--radius-md, 12px);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  cursor: pointer;
  transition: all 0.15s;
}

.elec-circuit-cell:hover {
  background: rgba(56, 189, 248, 0.12);
  border-color: rgba(56, 189, 248, 0.4);
}

.elec-circuit-cell.filled {
  background: rgba(56, 189, 248, 0.15);
  border: 1px solid rgba(56, 189, 248, 0.5);
  animation: elec-glow 2s ease-in-out infinite;
}

/* Toolbar */
.elec-circuit-toolbar {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
  margin-bottom: var(--space-4);
  padding: var(--space-3);
  background: var(--color-surface-2);
  border-radius: var(--radius-md, 12px);
}

.elec-circuit-tool {
  padding: var(--space-2) var(--space-3);
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md, 12px);
  font-size: var(--text-sm);
  font-weight: 600;
  cursor: pointer;
  font-family: inherit;
  transition: all 0.15s;
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.elec-circuit-tool:hover {
  border-color: #38bdf8;
}

.elec-circuit-tool.selected {
  border-color: #38bdf8;
  background: rgba(56, 189, 248, 0.15);
  color: #38bdf8;
  box-shadow: 0 0 10px rgba(56, 189, 248, 0.2);
}

/* Challenge card */
.elec-circuit-challenge {
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg, 16px);
  padding: var(--space-4);
  margin-bottom: var(--space-4);
}

.elec-circuit-challenge h3 {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  margin: 0 0 var(--space-2);
}

.elec-circuit-hint {
  padding: var(--space-3) var(--space-4);
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid rgba(245, 158, 11, 0.25);
  border-radius: var(--radius-md, 12px);
  font-size: var(--text-sm);
  color: #f59e0b;
  margin-top: var(--space-3);
}

.elec-circuit-result {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.6);
  z-index: 100;
  animation: elec-fadeIn 0.3s ease;
}

.elec-circuit-result > div {
  background: var(--color-surface);
  border-radius: var(--radius-lg, 16px);
  padding: var(--space-6);
  text-align: center;
  max-width: 400px;
  width: 90%;
}

/* ---- BUTTONS ---- */
.elec-btn {
  padding: 10px 20px;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-lg, 16px);
  background: var(--color-surface, #fff);
  cursor: pointer;
  font-weight: 600;
  font-size: 0.85rem;
  transition: all 0.2s;
}
.elec-btn:hover {
  border-color: #38bdf8;
  background: var(--color-surface-2);
}
.elec-btn.primary {
  background: #38bdf8;
  color: white;
  border-color: #38bdf8;
}
.elec-btn.primary:hover {
  background: #0284c7;
}
.elec-circuit-actions {
  display: flex;
  gap: var(--space-2);
  justify-content: center;
  flex-wrap: wrap;
  margin-top: var(--space-3);
}

/* ---- SENSOR SIMULATOR (Intermediate Lab) ---- */
.elec-sensor-wrap {
  max-width: 600px;
  margin: 0 auto;
  padding-bottom: var(--space-8);
}

.elec-sensor-build {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: var(--space-3);
  margin-bottom: var(--space-4);
}

.elec-sensor-card {
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md, 12px);
  padding: var(--space-4);
  text-align: center;
  cursor: pointer;
  transition: all 0.15s;
}

.elec-sensor-card:hover {
  border-color: #06b6d4;
  transform: translateY(-2px);
}

.elec-sensor-card.selected {
  border-color: #06b6d4;
  background: rgba(6, 182, 212, 0.1);
  box-shadow: 0 0 12px rgba(6, 182, 212, 0.25);
}

.elec-sensor-card .emoji {
  font-size: 2rem;
  margin-bottom: var(--space-2);
}

.elec-sensor-card .label {
  font-weight: 700;
  font-size: var(--text-sm);
}

/* Threshold slider */
.elec-sensor-threshold {
  padding: var(--space-4);
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md, 12px);
  margin-bottom: var(--space-4);
}

.elec-sensor-threshold input[type="range"] {
  width: 100%;
  accent-color: #06b6d4;
}

/* Test phase */
.elec-sensor-test {
  max-width: 600px;
  margin: 0 auto;
}

.elec-sensor-scenario {
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg, 16px);
  padding: var(--space-5);
  margin-bottom: var(--space-4);
  text-align: center;
}

.elec-sensor-scenario .scene-emoji {
  font-size: 3rem;
  margin-bottom: var(--space-2);
}

.elec-sensor-predict {
  display: flex;
  gap: var(--space-3);
  justify-content: center;
  margin-top: var(--space-4);
}

.elec-sensor-predict button {
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-full, 50px);
  font-weight: 700;
  font-size: var(--text-base);
  cursor: pointer;
  border: 2px solid var(--color-border);
  background: var(--color-surface);
  font-family: inherit;
  transition: all 0.15s;
  min-width: 100px;
}

.elec-sensor-predict button:hover { transform: translateY(-1px); }

.elec-sensor-predict button.on-btn {
  border-color: #22c55e;
  color: #22c55e;
}
.elec-sensor-predict button.on-btn:hover {
  background: rgba(34, 197, 94, 0.1);
}

.elec-sensor-predict button.off-btn {
  border-color: #ef4444;
  color: #ef4444;
}
.elec-sensor-predict button.off-btn:hover {
  background: rgba(239, 68, 68, 0.1);
}

.elec-sensor-result {
  text-align: center;
  padding: var(--space-6);
}

.elec-sensor-result h2 {
  font-family: var(--font-display);
  margin: 0 0 var(--space-2);
}

/* ---- CODE LAB (Advanced Lab) ---- */
.elec-code-wrap {
  max-width: 650px;
  margin: 0 auto;
  padding-bottom: var(--space-8);
}

.elec-code-blocks {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
}

.elec-code-block {
  padding: var(--space-3) var(--space-4);
  background: #1e293b;
  border: 2px solid rgba(129, 140, 248, 0.3);
  border-radius: var(--radius-md, 12px);
  font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  font-size: var(--text-sm);
  color: #f1f5f9;
  cursor: grab;
  transition: all 0.15s;
  user-select: none;
}

.elec-code-block:hover {
  border-color: #818cf8;
  background: #253049;
}

.elec-code-block:active {
  cursor: grabbing;
}

.elec-code-block.placed {
  opacity: 0.4;
  cursor: default;
  border-style: dashed;
}

/* Drop slots */
.elec-code-slot {
  min-height: 48px;
  padding: var(--space-3) var(--space-4);
  background: rgba(129, 140, 248, 0.06);
  border: 2px dashed rgba(129, 140, 248, 0.3);
  border-radius: var(--radius-md, 12px);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  font-size: var(--text-sm);
  color: rgba(129, 140, 248, 0.5);
  transition: all 0.15s;
  margin-bottom: var(--space-2);
}

.elec-code-slot:hover {
  border-color: #818cf8;
  background: rgba(129, 140, 248, 0.1);
}

.elec-code-slot.filled {
  background: #1e293b;
  border: 2px solid #818cf8;
  color: #f1f5f9;
}

/* Output / simulation */
.elec-code-output {
  padding: var(--space-4);
  background: #0f172a;
  border: 1px solid rgba(56, 189, 248, 0.2);
  border-radius: var(--radius-md, 12px);
  font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  font-size: var(--text-sm);
  color: #38bdf8;
  min-height: 80px;
  margin-bottom: var(--space-4);
  white-space: pre-wrap;
}

.elec-code-led {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: #374151;
  display: inline-block;
  transition: background 0.2s;
  box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.4);
}

.elec-code-led.on {
  background: #22c55e;
  box-shadow: 0 0 12px rgba(34, 197, 94, 0.6), inset 0 1px 3px rgba(255, 255, 255, 0.2);
  animation: elec-blink 1.2s ease-in-out infinite;
}

.elec-code-led.on-red {
  background: #ef4444;
  box-shadow: 0 0 12px rgba(239, 68, 68, 0.6), inset 0 1px 3px rgba(255, 255, 255, 0.2);
  animation: elec-blink 1.2s ease-in-out infinite;
}

.elec-code-led.on-blue {
  background: #38bdf8;
  box-shadow: 0 0 12px rgba(56, 189, 248, 0.6), inset 0 1px 3px rgba(255, 255, 255, 0.2);
  animation: elec-blink 1.2s ease-in-out infinite;
}

.elec-code-run {
  padding: var(--space-3) var(--space-6);
  background: linear-gradient(135deg, #818cf8, #6366f1);
  color: #fff;
  border: none;
  border-radius: var(--radius-full, 50px);
  font-weight: 700;
  font-size: var(--text-base);
  cursor: pointer;
  font-family: inherit;
  display: block;
  margin: var(--space-4) auto;
  transition: all 0.15s;
}

.elec-code-run:hover {
  filter: brightness(1.1);
  transform: translateY(-1px);
}

.elec-code-sim {
  padding: var(--space-4);
  background: #1e293b;
  border: 2px solid rgba(56, 189, 248, 0.2);
  border-radius: var(--radius-lg, 16px);
  text-align: center;
  margin-bottom: var(--space-4);
}

/* Code Lab: section wrappers for setup()/loop() */
.elec-code-section {
  background: #0d0e18;
  border-radius: 12px;
  border: 2px solid #1e1f2e;
  padding: 14px;
  margin-bottom: 12px;
}

.elec-code-section.error-border {
  border-color: #f87171;
}

.elec-code-section.compact {
  padding: 10px;
  margin-bottom: 10px;
}

.elec-code-header {
  font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  font-size: 13px;
  color: #c084fc;
  margin-bottom: 4px;
}

.elec-code-footer {
  font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  font-size: 13px;
  color: #e2e8f0;
}

.elec-code-slots {
  padding-left: 12px;
  min-height: 32px;
  border-left: 2px solid rgba(129, 140, 248, 0.2);
  margin-bottom: 4px;
}

.elec-code-slots.loop-slots {
  border-left-color: rgba(52, 211, 153, 0.2);
}

.elec-code-slot.empty {
  color: #64748b;
  font-size: 12px;
  font-style: italic;
  padding: 4px 0;
  border: none;
  background: none;
  min-height: auto;
  justify-content: flex-start;
}

.elec-code-block.available {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 7px 10px;
  background: #0d0e18;
  border-radius: 8px;
  border: 1px solid #1e1f2e;
  font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  font-size: 13px;
  color: #e2e8f0;
  cursor: pointer;
  transition: all 0.15s;
  opacity: 1;
  border-style: solid;
  width: 100%;
  text-align: left;
}

.elec-code-block.available:hover {
  border-color: #818cf8;
  background: #12131f;
}

.elec-code-block.available.selected {
  border-color: #818cf8;
  background: rgba(129, 140, 248, 0.15);
  box-shadow: 0 0 8px rgba(129, 140, 248, 0.3);
}

.elec-code-block.placed-slot {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 7px 10px;
  background: #0d0e18;
  border-radius: 8px;
  border: 1px solid #1e1f2e;
  font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  font-size: 13px;
  color: #e2e8f0;
  cursor: pointer;
  opacity: 1;
  border-style: solid;
  margin-bottom: 3px;
}

.elec-code-block.placed-slot:hover {
  border-color: #f87171;
}

.elec-code-block.placed-slot .elec-block-remove {
  color: #f87171;
  opacity: 0.7;
  margin-left: 4px;
  font-size: 14px;
}

.elec-code-block.placed-slot.correct-block {
  border-color: #34d399;
  background: rgba(52, 211, 153, 0.1);
}

.elec-code-block.placed-slot.wrong-block {
  border-color: #f87171;
  background: rgba(248, 113, 113, 0.1);
}

.elec-block-desc {
  color: #64748b;
  font-size: 10px;
  white-space: nowrap;
}

.elec-block-num {
  color: #3b3c50;
  font-size: 11px;
  min-width: 16px;
}

.elec-place-buttons {
  display: flex;
  gap: 8px;
  margin: 10px 0;
  flex-wrap: wrap;
}

/* Code Lab: simulation output */
.elec-sim-section {
  padding: 20px;
  background: #0d0e18;
  border-radius: 14px;
  border: 2px solid rgba(52, 211, 153, 0.25);
  margin-bottom: 14px;
}

.elec-sim-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 14px;
}

.elec-sim-status {
  color: #34d399;
  font-weight: bold;
  font-size: 14px;
}

.elec-sim-step-label {
  color: #64748b;
  font-size: 12px;
}

.elec-sim-outputs {
  display: flex;
  gap: 16px;
  justify-content: center;
  margin-bottom: 14px;
  flex-wrap: wrap;
}

.elec-sim-output-card {
  padding: 14px 20px;
  border-radius: 12px;
  text-align: center;
  min-width: 80px;
  transition: all 0.3s;
}

.elec-sim-output-card.off {
  background: #12131f;
  border: 2px solid #1e1f2e;
}

.elec-sim-output-icon {
  font-size: 32px;
  transition: all 0.3s;
}

.elec-sim-output-pin {
  font-size: 12px;
  font-weight: bold;
  margin-top: 4px;
}

.elec-sim-output-state {
  font-size: 11px;
  margin-top: 2px;
}

.elec-sim-label {
  text-align: center;
  padding: 8px 14px;
  border-radius: 8px;
  background: rgba(129, 140, 248, 0.1);
  color: #e2e8f0;
  font-size: 15px;
  font-weight: bold;
  margin-bottom: 10px;
}

.elec-sim-progress-bar {
  height: 6px;
  border-radius: 3px;
  background: #1e1f2e;
  overflow: hidden;
}

.elec-sim-progress-fill {
  height: 100%;
  border-radius: 3px;
  background: linear-gradient(90deg, #818cf8, #34d399);
  transition: width 0.4s ease;
}

/* Code Lab: code editor view (dark, syntax-highlighted) */
.elec-code-editor {
  background: #0d0e18;
  border-radius: 10px;
  padding: 14px;
  margin-bottom: 14px;
  border: 1px solid #1e1f2e;
  font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  font-size: 12px;
  line-height: 1.6;
  overflow-x: auto;
}

.elec-code-editor .code-line {
  display: flex;
  align-items: center;
  padding: 1px 0;
}

.elec-code-editor .code-line.active-line {
  background: rgba(129, 140, 248, 0.12);
  border-radius: 3px;
}

.elec-code-editor .line-num {
  color: #3b3c50;
  min-width: 28px;
  text-align: right;
  margin-right: 12px;
  user-select: none;
}

/* Syntax colors */
.elec-syn-keyword { color: #c084fc; }
.elec-syn-func { color: #67e8f9; }
.elec-syn-string { color: #86efac; }
.elec-syn-number { color: #fcd34d; }
.elec-syn-comment { color: #4b5563; }
.elec-syn-teal { color: #2dd4bf; }

/* Code Lab: result phase */
.elec-code-result {
  padding: 16px;
  border-radius: 12px;
  margin-bottom: 14px;
  text-align: center;
  background: linear-gradient(135deg, rgba(52, 211, 153, 0.08), rgba(129, 140, 248, 0.08));
  border: 1px solid rgba(52, 211, 153, 0.25);
}

.elec-code-result h3 {
  color: #34d399;
  font-weight: bold;
  font-size: 17px;
  margin: 8px 0 4px;
}

.elec-code-result p {
  color: #e2e8f0;
  font-size: 13px;
  margin-top: 4px;
}

.elec-code-stars {
  font-size: 28px;
  margin: 8px 0;
}

.elec-code-xp {
  color: #818cf8;
  font-size: 14px;
  font-weight: bold;
  margin-bottom: 8px;
}

/* Hint box */
.elec-code-hint {
  margin-top: 10px;
  padding: 10px 14px;
  background: rgba(251, 191, 36, 0.08);
  border-radius: 10px;
  color: #fbbf24;
  font-size: 13px;
  border-left: 3px solid #fbbf24;
}

/* Error feedback */
.elec-code-error {
  margin-top: 10px;
  padding: 10px 14px;
  background: rgba(248, 113, 113, 0.08);
  border-radius: 10px;
  color: #f87171;
  font-size: 14px;
  border-left: 3px solid #f87171;
}

/* Story and concept display */
.elec-code-story {
  padding: 12px 16px;
  background: rgba(129, 140, 248, 0.06);
  border-radius: 10px;
  border-left: 3px solid #818cf8;
  margin-bottom: 10px;
  font-size: 14px;
  color: #e2e8f0;
  line-height: 1.6;
}

.elec-code-concept {
  padding: 6px 12px;
  background: #0d0e18;
  border-radius: 6px;
  margin-bottom: 14px;
  font-size: 12px;
  color: #64748b;
}

/* Available blocks label */
.elec-available-label {
  color: #fbbf24;
  font-weight: bold;
  font-size: 13px;
  margin-bottom: 6px;
}

.elec-available-sublabel {
  color: #64748b;
  font-weight: normal;
}

.elec-available-blocks {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin-bottom: 12px;
}

/* ---- RESPONSIVE ---- */
@media (max-width: 600px) {
  .elec-card-grid {
    grid-template-columns: 1fr;
  }

  .elec-circuit-grid {
    grid-template-columns: repeat(auto-fill, minmax(48px, 1fr));
  }

  .elec-circuit-cell {
    min-height: 48px;
    font-size: 1.2rem;
  }

  .elec-sensor-build {
    grid-template-columns: repeat(2, 1fr);
  }

  .elec-code-block,
  .elec-code-slot {
    font-size: var(--text-xs);
    padding: var(--space-2) var(--space-3);
  }

  .elec-lesson-heading {
    font-size: var(--text-lg);
  }

  .elec-quiz-question {
    font-size: var(--text-base);
  }

  .elec-lesson-nav {
    flex-direction: column;
  }

  .elec-lesson-nav button {
    width: 100%;
  }

  .elec-sensor-predict {
    flex-direction: column;
  }

  .elec-sensor-predict button {
    width: 100%;
  }
}