/* ======== ENGINEERING LAB STYLES ======== */
/* Merged from Circuit Lab + Robotics Lab — theme: cyan/teal #06b6d4 */

.eng-lab-home { max-width: 700px; margin: 0 auto; padding-bottom: var(--space-8); }

/* Header */
.eng-lab-header {
  text-align: center;
  padding: var(--space-6) var(--space-4);
  background: linear-gradient(135deg, var(--color-surface-2), var(--color-primary-surface));
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-4);
  border: 1px solid var(--color-border);
}
.eng-lab-header-icon { font-size: 3.5rem; margin-bottom: var(--space-2); }
.eng-lab-header h1 { font-family: var(--font-display); font-size: var(--text-xl); margin: 0 0 var(--space-2); color: var(--color-text); }
.eng-lab-header p { color: var(--color-text-muted); margin: 0; font-size: var(--text-sm); }

/* Stats bar */
.eng-lab-stats-bar {
  display: flex; gap: var(--space-3); margin-bottom: var(--space-6);
}
.eng-lab-stat-item {
  flex: 1; text-align: center; padding: var(--space-3);
  background: var(--color-surface); border: 2px solid var(--color-border);
  border-radius: var(--radius-lg);
}
.eng-lab-stat-value { font-family: var(--font-display); font-size: var(--text-lg); font-weight: 700; color: var(--color-text); }
.eng-lab-stat-label { font-size: var(--text-xs); color: var(--color-text-muted); font-weight: 600; text-transform: uppercase; }

/* Section titles */
.eng-lab-section-title {
  font-family: var(--font-display); font-size: var(--text-lg);
  margin: var(--space-6) 0 var(--space-3); color: var(--color-text);
}

/* Tier cards grid */
.eng-lab-tier-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: var(--space-3); margin-bottom: var(--space-4);
}
.eng-lab-tier-card, .eng-lab-challenge-card {
  background: var(--color-surface); border: 2px solid var(--color-border);
  border-radius: var(--radius-lg); padding: var(--space-4);
  cursor: pointer; transition: all 0.2s; text-align: center;
}
.eng-lab-tier-card:hover, .eng-lab-challenge-card:hover {
  transform: translateY(-3px); border-color: #06b6d4;
  box-shadow: var(--shadow-md);
}
.eng-lab-tier-emoji { font-size: 2.5rem; margin-bottom: var(--space-2); }
.eng-lab-tier-name { font-family: var(--font-display); font-size: var(--text-base); font-weight: 700; color: var(--color-text); }
.eng-lab-tier-badge {
  display: inline-block; padding: 2px 10px; border-radius: var(--radius-full);
  font-size: 0.65rem; font-weight: 700; text-transform: uppercase;
  background: var(--color-success); color: white; margin: var(--space-1) 0;
}
.eng-lab-badge-inter { background: #06b6d4; }
.eng-lab-badge-adv { background: var(--color-error); }
.eng-lab-tier-desc { font-size: var(--text-xs); color: var(--color-text-muted); margin: var(--space-2) 0; }
.eng-lab-tier-progress { font-size: var(--text-xs); color: var(--color-text-muted); font-weight: 600; }
.eng-lab-tier-bar {
  height: 6px; background: var(--color-surface-offset); border-radius: 3px;
  overflow: hidden; margin-top: var(--space-2);
}
.eng-lab-tier-fill {
  height: 100%; background: #06b6d4; border-radius: 3px;
  transition: width 0.5s;
}

/* Quiz cards on home */
.eng-lab-quiz-card {
  background: var(--color-surface); border: 2px solid var(--color-border);
  border-radius: var(--radius-lg); padding: var(--space-3) var(--space-4);
  cursor: pointer; transition: all 0.2s;
  display: flex; align-items: center; gap: var(--space-3);
  font-weight: 600; font-size: var(--text-sm); color: var(--color-text);
}
.eng-lab-quiz-card:hover { transform: translateY(-2px); border-color: #06b6d4; }
.eng-lab-quiz-score { margin-left: auto; color: #06b6d4; font-weight: 700; }

/* ======== STUDY CARDS ======== */
.eng-lab-study { max-width: 700px; margin: 0 auto; }

.eng-lab-back-bar {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: var(--space-4);
}
.eng-lab-back-btn {
  display: flex; align-items: center; gap: var(--space-2);
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius-full); padding: var(--space-2) var(--space-4);
  color: #06b6d4; font-weight: 600; font-size: var(--text-sm);
  cursor: pointer; transition: all 0.2s;
}
.eng-lab-back-btn:hover { background: rgba(6,182,212,0.08); }
.eng-lab-back-btn svg { width: 16px; height: 16px; }
.eng-lab-progress-pill {
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius-full); padding: var(--space-1) var(--space-3);
  font-size: var(--text-sm); font-weight: 600; color: var(--color-text-muted);
}

.eng-lab-progress-bar-wrap { margin-bottom: var(--space-3); }
.eng-lab-progress-bar {
  height: 8px; background: var(--color-surface-offset); border-radius: 4px; overflow: hidden;
}
.eng-lab-progress-fill {
  height: 100%; background: #06b6d4; border-radius: 4px; transition: width 0.5s;
}

/* Dots */
.eng-lab-dots {
  display: flex; justify-content: center; gap: 8px;
  margin-bottom: var(--space-4); flex-wrap: wrap;
}
.eng-lab-dot {
  width: 12px; height: 12px; border-radius: 50%;
  background: var(--color-border); cursor: pointer; transition: all 0.2s;
}
.eng-lab-dot.active { background: #06b6d4; transform: scale(1.3); }
.eng-lab-dot.learned { background: var(--color-success); }
.eng-lab-dot.learned.active { background: var(--color-success); transform: scale(1.3); box-shadow: 0 0 6px rgba(91,184,122,0.4); }

/* Single card container */
.eng-lab-card-single { max-width: 460px; margin: 0 auto; overflow: hidden; }

/* Topic card */
.eng-lab-topic-card {
  background: var(--color-surface); border: 2px solid var(--color-border);
  border-radius: var(--radius-lg); padding: var(--space-4); transition: all 0.2s;
}
.eng-lab-topic-card.eng-lab-topic-learned { border-color: var(--color-success); }
.eng-lab-card-top { display: flex; justify-content: space-between; align-items: center; margin-bottom: var(--space-2); }
.eng-lab-card-number { font-size: var(--text-sm); color: var(--color-text-muted); font-weight: 600; }

.eng-lab-card-emoji { font-size: 2.5rem; margin-bottom: var(--space-2); }
.eng-lab-card-name { font-family: var(--font-display); font-size: var(--text-lg); font-weight: 700; color: var(--color-text); margin-bottom: var(--space-1); }
.eng-lab-card-desc { font-size: var(--text-sm); color: var(--color-text); line-height: 1.5; margin: 0 0 var(--space-3); }

.eng-lab-card-section { margin-bottom: var(--space-3); font-size: var(--text-sm); line-height: 1.5; color: var(--color-text); }
.eng-lab-card-section strong { display: block; margin-bottom: var(--space-1); }
.eng-lab-card-section p { margin: 0; color: var(--color-text-muted); }

.eng-lab-card-funfact {
  background: var(--feedback-info-bg); border-radius: var(--radius-md);
  padding: var(--space-3); border: 1px solid var(--feedback-info-border);
}
.eng-lab-card-funfact strong { color: var(--feedback-info-text); }
.eng-lab-card-funfact p { color: var(--feedback-info-text); }

.eng-lab-card-example {
  background: rgba(6,182,212,0.06); border-radius: var(--radius-md);
  padding: var(--space-3); border: 1px solid var(--color-border);
}
.eng-lab-card-example strong { color: #06b6d4; }

/* Learned badge */
.eng-lab-learned-badge {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 4px 12px; border-radius: var(--radius-full);
  background: var(--feedback-correct-bg); color: var(--feedback-correct-text);
  font-size: var(--text-xs); font-weight: 700;
  border: 1px solid var(--feedback-correct-border);
}

/* Check understanding button */
.eng-lab-check-btn {
  display: block; width: 100%; margin-top: var(--space-4);
  padding: var(--space-3); background: #06b6d4;
  color: white; border: none; border-radius: var(--radius-md);
  font-family: var(--font-display); font-size: var(--text-base);
  font-weight: 700; cursor: pointer; transition: all 0.2s;
}
.eng-lab-check-btn:hover { background: #0891b2; transform: translateY(-1px); }

/* Mini quiz */
.eng-lab-mini-quiz {
  margin-top: var(--space-4); padding-top: var(--space-4);
  border-top: 2px dashed var(--color-border);
}
.eng-lab-mini-quiz-q {
  font-family: var(--font-display); font-size: var(--text-base);
  font-weight: 700; color: var(--color-text); margin-bottom: var(--space-3);
  line-height: 1.4;
}
.eng-lab-mini-quiz-opts {
  display: flex; flex-direction: column; gap: var(--space-2);
}
.eng-lab-mini-opt {
  padding: var(--space-2) var(--space-3);
  background: var(--color-surface-2); border: 2px solid var(--color-border);
  border-radius: var(--radius-md); font-size: var(--text-sm);
  color: var(--color-text); cursor: pointer; transition: all 0.2s;
  text-align: left; font-weight: 500;
}
.eng-lab-mini-opt:hover:not(:disabled) { border-color: #06b6d4; background: rgba(6,182,212,0.08); }
.eng-lab-mini-opt.correct { background: var(--feedback-correct-bg); border-color: var(--feedback-correct-border); color: var(--feedback-correct-text); font-weight: 700; }
.eng-lab-mini-opt.wrong { background: var(--feedback-wrong-bg); border-color: var(--feedback-wrong-border); color: var(--feedback-wrong-text); }

.eng-lab-mini-result {
  margin-top: var(--space-3); padding: var(--space-3);
  border-radius: var(--radius-md); font-size: var(--text-sm);
  font-weight: 600; text-align: center;
}
.eng-lab-mini-result.correct { background: var(--feedback-correct-bg); color: var(--feedback-correct-text); border: 1px solid var(--feedback-correct-border); }
.eng-lab-mini-result.wrong { background: var(--feedback-wrong-bg); color: var(--feedback-wrong-text); border: 1px solid var(--feedback-wrong-border); }
.eng-lab-mini-retry {
  display: inline-block; margin-top: var(--space-2);
  padding: var(--space-1) var(--space-3); background: var(--color-surface);
  border: 1px solid var(--color-border); border-radius: var(--radius-full);
  font-size: var(--text-xs); font-weight: 700; cursor: pointer;
  color: var(--color-text);
}
.eng-lab-mini-retry:hover { border-color: #06b6d4; }

/* Nav buttons */
.eng-lab-nav {
  display: flex; align-items: center; justify-content: center;
  gap: var(--space-4); margin-top: var(--space-4); padding: var(--space-3) 0;
}
.eng-lab-nav-btn {
  display: flex; align-items: center; gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: var(--color-surface); border: 2px solid var(--color-border);
  border-radius: var(--radius-full); color: var(--color-text);
  font-weight: 700; font-size: var(--text-sm); cursor: pointer; transition: all 0.2s;
}
.eng-lab-nav-btn:hover { border-color: #06b6d4; color: #06b6d4; transform: translateY(-1px); }
.eng-lab-nav-btn svg { width: 18px; height: 18px; }
.eng-lab-nav-counter { font-family: var(--font-display); font-size: var(--text-base); font-weight: 700; color: var(--color-text-muted); min-width: 60px; text-align: center; }

/* Slide animations */
.eng-lab-slide-out-left { animation: engLabSlideOutLeft 0.15s ease forwards; }
.eng-lab-slide-out-right { animation: engLabSlideOutRight 0.15s ease forwards; }
@keyframes engLabSlideOutLeft { from { transform: translateX(0); opacity: 1; } to { transform: translateX(-40px); opacity: 0; } }
@keyframes engLabSlideOutRight { from { transform: translateX(0); opacity: 1; } to { transform: translateX(40px); opacity: 0; } }

/* ======== QUIZ ======== */
.eng-lab-quiz { max-width: 600px; margin: 0 auto; }
.eng-lab-quiz-progress { margin-bottom: var(--space-4); }
.eng-lab-quiz-progress-bar { height: 8px; background: var(--color-surface-offset); border-radius: 4px; overflow: hidden; margin-bottom: var(--space-2); }
.eng-lab-quiz-progress-fill { height: 100%; background: #06b6d4; border-radius: 4px; transition: width 0.3s; }
.eng-lab-quiz-counter { text-align: center; font-size: var(--text-sm); color: var(--color-text-muted); font-weight: 600; }

.eng-lab-quiz-card {
  background: var(--color-surface); border: 2px solid var(--color-border);
  border-radius: var(--radius-lg); padding: var(--space-5);
  display: flex; flex-direction: column;
}
.eng-lab-quiz-question {
  font-family: var(--font-display); font-size: var(--text-lg);
  color: var(--color-text); margin-bottom: var(--space-4); line-height: 1.4;
}
.eng-lab-quiz-options { display: flex; flex-direction: column; gap: var(--space-2); width: 100%; }
.eng-lab-quiz-opt {
  display: flex; align-items: center; gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  background: var(--color-surface-2); border: 2px solid var(--color-border);
  border-radius: var(--radius-md); font-size: var(--text-sm);
  color: var(--color-text); cursor: pointer; transition: all 0.2s;
  text-align: left; font-weight: 500;
}
.eng-lab-quiz-opt:hover:not(:disabled) { border-color: #06b6d4; background: rgba(6,182,212,0.08); }
.eng-lab-quiz-opt.correct { background: var(--feedback-correct-bg); border-color: var(--feedback-correct-border); color: var(--feedback-correct-text); }
.eng-lab-quiz-opt.wrong { background: var(--feedback-wrong-bg); border-color: var(--feedback-wrong-border); color: var(--feedback-wrong-text); }
.eng-lab-opt-letter {
  display: inline-flex; align-items: center; justify-content: center;
  width: 28px; height: 28px; border-radius: 50%;
  background: var(--color-border); font-weight: 700; font-size: var(--text-xs);
  color: var(--color-text); flex-shrink: 0;
}
.eng-lab-quiz-opt.correct .eng-lab-opt-letter { background: var(--feedback-correct-border); color: white; }
.eng-lab-quiz-opt.wrong .eng-lab-opt-letter { background: var(--feedback-wrong-border); color: white; }

.eng-lab-quiz-explanation {
  margin-top: var(--space-3); padding: var(--space-3);
  border-radius: var(--radius-md); font-size: var(--text-sm); line-height: 1.5;
}
.eng-lab-quiz-explanation.correct { background: var(--feedback-correct-bg); color: var(--feedback-correct-text); }
.eng-lab-quiz-explanation.wrong { background: var(--feedback-wrong-bg); color: var(--feedback-wrong-text); }

.eng-lab-quiz-next-btn {
  display: block; width: 100%; margin-top: var(--space-3);
  padding: var(--space-3); background: #06b6d4;
  color: white; border: none; border-radius: var(--radius-md);
  font-weight: 700; font-size: var(--text-sm); cursor: pointer; transition: all 0.2s;
}
.eng-lab-quiz-next-btn:hover { background: #0891b2; }

/* Quiz results */
.eng-lab-quiz-results {
  max-width: 400px; margin: var(--space-8) auto; text-align: center;
  background: var(--color-surface); border: 2px solid var(--color-border);
  border-radius: var(--radius-lg); padding: var(--space-6);
}
.eng-lab-results-emoji { font-size: 4rem; margin-bottom: var(--space-3); }
.eng-lab-quiz-results h2 { font-family: var(--font-display); font-size: var(--text-xl); color: var(--color-text); margin: 0 0 var(--space-3); }
.eng-lab-results-score { font-family: var(--font-display); font-size: var(--text-2xl); color: #06b6d4; font-weight: 700; }
.eng-lab-results-stars { font-size: 2rem; margin: var(--space-2) 0; }
.eng-lab-results-msg { color: var(--color-text-muted); font-size: var(--text-sm); margin-bottom: var(--space-4); }
.eng-lab-results-btns { display: flex; gap: var(--space-3); justify-content: center; flex-wrap: wrap; }

.eng-lab-btn-primary {
  padding: var(--space-3) var(--space-5); background: #06b6d4;
  color: white; border: none; border-radius: var(--radius-full);
  font-weight: 700; font-size: var(--text-sm); cursor: pointer; transition: all 0.2s;
}
.eng-lab-btn-primary:hover { background: #0891b2; transform: translateY(-1px); }
.eng-lab-btn-secondary {
  padding: var(--space-3) var(--space-5); background: var(--color-surface);
  color: var(--color-text); border: 2px solid var(--color-border);
  border-radius: var(--radius-full); font-weight: 700; font-size: var(--text-sm);
  cursor: pointer; transition: all 0.2s;
}
.eng-lab-btn-secondary:hover { border-color: #06b6d4; }

/* ======== CHALLENGES ======== */
.eng-lab-challenge { max-width: 600px; margin: 0 auto; }

/* Build Robot */
.eng-lab-build-layout {
  display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-4);
  margin-top: var(--space-4);
}
@media (max-width: 600px) { .eng-lab-build-layout { grid-template-columns: 1fr; } }

.eng-lab-build-robot {
  display: flex; flex-direction: column; align-items: center; gap: var(--space-2);
  padding: var(--space-4);
  background: var(--color-surface); border: 2px dashed var(--color-border);
  border-radius: var(--radius-lg);
}
.eng-lab-build-slot {
  width: 100%; max-width: 200px; padding: var(--space-3);
  background: var(--color-surface-2); border: 2px dashed var(--color-border);
  border-radius: var(--radius-md); text-align: center;
  font-size: var(--text-sm); font-weight: 600; cursor: pointer;
  transition: all 0.2s; color: var(--color-text);
}
.eng-lab-build-slot.correct { border-color: var(--feedback-correct-border); background: var(--feedback-correct-bg); border-style: solid; }
.eng-lab-build-slot.wrong { border-color: var(--feedback-wrong-border); background: var(--feedback-wrong-bg); border-style: solid; }
.eng-lab-slot-label { color: var(--color-text-faint); font-size: var(--text-xs); text-transform: uppercase; }

.eng-lab-build-parts { padding: var(--space-3); }
.eng-lab-build-parts h3 { font-family: var(--font-display); font-size: var(--text-base); margin: 0 0 var(--space-3); color: var(--color-text); }
.eng-lab-build-part-btn {
  display: block; width: 100%; margin-bottom: var(--space-2);
  padding: var(--space-2) var(--space-3);
  background: rgba(6,182,212,0.08); border: 2px solid #06b6d4;
  border-radius: var(--radius-md); font-weight: 600; font-size: var(--text-sm);
  color: var(--color-text); cursor: pointer; transition: all 0.2s; text-align: left;
}
.eng-lab-build-part-btn:hover { background: #06b6d4; color: white; }

.eng-lab-build-result {
  margin-top: var(--space-4); padding: var(--space-4);
  border-radius: var(--radius-md); text-align: center;
  font-weight: 600; font-size: var(--text-sm);
}
.eng-lab-build-result.correct { background: var(--feedback-correct-bg); color: var(--feedback-correct-text); border: 1px solid var(--feedback-correct-border); }
.eng-lab-build-result.wrong { background: var(--feedback-wrong-bg); color: var(--feedback-wrong-text); border: 1px solid var(--feedback-wrong-border); }

/* Sequence Challenge */
.eng-lab-sequence-placed, .eng-lab-sequence-available {
  margin-top: var(--space-4);
}
.eng-lab-sequence-placed h3, .eng-lab-sequence-available h3 {
  font-family: var(--font-display); font-size: var(--text-base);
  margin: 0 0 var(--space-3); color: var(--color-text);
}
.eng-lab-empty-hint { color: var(--color-text-faint); font-style: italic; font-size: var(--text-sm); }

.eng-lab-seq-block {
  display: flex; align-items: center; gap: var(--space-2);
  padding: var(--space-3) var(--space-4); margin-bottom: var(--space-2);
  background: var(--color-surface); border: 2px solid var(--color-border);
  border-radius: var(--radius-md); font-size: var(--text-sm); font-weight: 600;
  color: var(--color-text); cursor: pointer; transition: all 0.2s;
}
.eng-lab-seq-block.available { background: rgba(6,182,212,0.08); border-color: #06b6d4; }
.eng-lab-seq-block.available:hover { background: #06b6d4; color: white; }
.eng-lab-seq-block.correct { background: var(--feedback-correct-bg); border-color: var(--feedback-correct-border); }
.eng-lab-seq-block.wrong { background: var(--feedback-wrong-bg); border-color: var(--feedback-wrong-border); }
.eng-lab-seq-num {
  display: inline-flex; align-items: center; justify-content: center;
  width: 24px; height: 24px; border-radius: 50%;
  background: var(--color-border); font-size: var(--text-xs); font-weight: 700;
  flex-shrink: 0;
}

/* Debug Challenge */
.eng-lab-debug-code {
  margin-top: var(--space-4);
  background: var(--color-surface); border: 2px solid var(--color-border);
  border-radius: var(--radius-lg); overflow: hidden;
  font-family: 'Courier New', monospace;
}
.eng-lab-code-line {
  display: flex; align-items: center; gap: var(--space-3);
  padding: var(--space-2) var(--space-3);
  border-bottom: 1px solid var(--color-divider);
  transition: all 0.2s; font-size: var(--text-sm); color: var(--color-text);
}
.eng-lab-code-line:last-child { border-bottom: none; }
.eng-lab-code-line.buggy { background: var(--feedback-wrong-bg); cursor: pointer; }
.eng-lab-code-line.buggy:hover { background: var(--feedback-wrong-light); }
.eng-lab-code-line.fixed { background: var(--feedback-correct-bg); }
.eng-lab-line-num {
  color: var(--color-text-faint); font-size: var(--text-xs);
  min-width: 20px; text-align: right; user-select: none;
}
.eng-lab-code-line code { flex: 1; white-space: pre-wrap; }

/* ======== HOME PAGE — compact layout ======== */

/* Stat pills */
.eng-lab-pill {
  padding: 5px 12px;
  border-radius: 12px;
  font-size: .74rem;
  font-weight: 700;
  background: rgba(6,182,212,0.08);
  border: 1px solid rgba(6,182,212,0.2);
  color: var(--color-text);
}

/* Lesson grid items */
.eng-lab-lesson-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 12px;
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.2s;
  min-height: 44px;
}
.eng-lab-lesson-item:hover {
  border-color: #06b6d4;
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}
.eng-lab-lesson-emoji {
  font-size: 1.3rem;
  flex-shrink: 0;
}
.eng-lab-lesson-name {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-text);
  flex: 1;
  line-height: 1.2;
}
.eng-lab-lesson-check {
  font-size: 0.85rem;
  flex-shrink: 0;
}

/* Action cards (Build / Challenge / Quiz) */
.eng-lab-action-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: 12px 8px;
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.2s;
  text-align: center;
}
.eng-lab-action-card:hover {
  border-color: #06b6d4;
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}
.eng-lab-action-emoji {
  font-size: 1.4rem;
}
.eng-lab-action-name {
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--color-text);
}

/* Responsive */
@media (max-width: 500px) {
  .eng-lab-tier-grid { grid-template-columns: 1fr; }
  .eng-lab-stats-bar { flex-direction: column; }
}