/* ==========================================================================
   DESIGN SYSTEM & CUSTOM PROPERTIES
   ========================================================================== */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Outfit:wght@400;500;600;700;800&display=swap');

:root {
  /* Colors */
  --bg-primary: #040914;
  --bg-secondary: #0a1424;
  --bg-card: rgba(13, 27, 42, 0.45);
  --bg-card-hover: rgba(16, 37, 66, 0.6);
  --border-color: rgba(0, 245, 212, 0.15);
  --border-color-hover: rgba(0, 245, 212, 0.35);
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  
  /* Accent Colors (Water Theme) */
  --accent-cyan: #00f5d4;
  --accent-blue: #00bbf9;
  --accent-purple: #7b2cbf;
  --accent-mercury: #e2e8f0;
  --accent-danger: #ff477e;
  --accent-success: #38b000;
  
  /* Gradients */
  --grad-primary: linear-gradient(135deg, var(--bg-primary) 0%, #0d1b2a 100%);
  --grad-water: linear-gradient(180deg, rgba(0, 245, 212, 0.8) 0%, rgba(0, 187, 249, 0.9) 100%);
  --grad-mercury: linear-gradient(180deg, #94a3b8 0%, #475569 100%);
  --grad-accent: linear-gradient(90deg, var(--accent-cyan), var(--accent-blue));
  
  /* Shadows & Effects */
  --glow-cyan: 0 0 15px rgba(0, 245, 212, 0.4);
  --glow-blue: 0 0 15px rgba(0, 187, 249, 0.4);
  --shadow-card: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
  --glass-blur: blur(12px);
  
  /* Layout */
  --border-radius-sm: 8px;
  --border-radius-md: 16px;
  --border-radius-lg: 24px;
  --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ==========================================================================
   RESET & BASE STYLES
   ========================================================================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Inter', sans-serif;
  background: var(--bg-primary);
  background-image: var(--grad-primary);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
  overflow-x: hidden;
}

h1, h2, h3, h4 {
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  letter-spacing: -0.02em;
}

/* Scrollbar styling */
::-webkit-scrollbar {
  width: 8px;
}
::-webkit-scrollbar-track {
  background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
  background: var(--bg-secondary);
  border-radius: 4px;
  border: 1px solid var(--border-color);
}
::-webkit-scrollbar-thumb:hover {
  background: rgba(0, 245, 212, 0.3);
}

/* ==========================================================================
   LAYOUT STRUCTURE
   ========================================================================== */
.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 2rem;
}

header {
  text-align: center;
  margin-bottom: 3rem;
  position: relative;
}

header h1 {
  font-size: 3rem;
  font-weight: 800;
  background: linear-gradient(135deg, #fff 30%, var(--accent-cyan) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 0.5rem;
  text-transform: tracking-tight;
}

header p {
  color: var(--text-secondary);
  font-size: 1.1rem;
  max-width: 600px;
  margin: 0 auto;
}

.badge {
  background: rgba(0, 245, 212, 0.1);
  border: 1px solid var(--border-color);
  color: var(--accent-cyan);
  padding: 0.3rem 0.8rem;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  display: inline-block;
  margin-bottom: 1rem;
}

.main-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 2rem;
  align-items: start;
}

@media (max-width: 1024px) {
  .main-grid {
    grid-template-columns: 1fr;
  }
}

/* ==========================================================================
   GLASSMOPHISM CARDS
   ========================================================================== */
.glass-card {
  background: var(--bg-card);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-md);
  padding: 2rem;
  box-shadow: var(--shadow-card);
  transition: var(--transition-smooth);
}

.glass-card:hover {
  border-color: var(--border-color-hover);
  background: var(--bg-card-hover);
  box-shadow: 0 12px 40px 0 rgba(0, 0, 0, 0.45);
}

.glass-card h2 {
  font-size: 1.8rem;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.75rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  padding-bottom: 0.75rem;
}

.glass-card h2 svg {
  color: var(--accent-cyan);
}

/* ==========================================================================
   SIMULATOR STYLING
   ========================================================================== */
.simulator-wrapper {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.canvas-container {
  position: relative;
  background: #020617;
  border-radius: var(--border-radius-md);
  border: 1px solid rgba(255, 255, 255, 0.05);
  overflow: hidden;
  box-shadow: inset 0 4px 30px rgba(0,0,0,0.8);
  aspect-ratio: 16 / 10;
  display: flex;
  justify-content: center;
  align-items: center;
}

canvas {
  display: block;
  width: 100%;
  height: 100%;
}

.controls-panel {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.preset-container {
  display: flex;
  gap: 0.75rem;
}

.btn-preset {
  flex: 1;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--text-secondary);
  padding: 0.75rem 1rem;
  border-radius: var(--border-radius-sm);
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-smooth);
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 0.5rem;
}

.btn-preset:hover {
  background: rgba(255, 255, 255, 0.08);
  color: var(--text-primary);
  border-color: rgba(255, 255, 255, 0.2);
}

.btn-preset.active[data-preset="water"] {
  background: rgba(0, 245, 212, 0.15);
  color: var(--accent-cyan);
  border-color: var(--accent-cyan);
  box-shadow: var(--glow-cyan);
}

.btn-preset.active[data-preset="mercury"] {
  background: rgba(148, 163, 184, 0.15);
  color: var(--accent-mercury);
  border-color: var(--accent-mercury);
  box-shadow: 0 0 15px rgba(148, 163, 184, 0.3);
}

.btn-preset.active[data-preset="custom"] {
  background: rgba(0, 187, 249, 0.15);
  color: var(--accent-blue);
  border-color: var(--accent-blue);
  box-shadow: var(--glow-blue);
}

.slider-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.slider-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.9rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.slider-value {
  color: var(--accent-cyan);
  font-weight: 700;
}

/* Custom Slider Styling */
.range-slider {
  -webkit-appearance: none;
  width: 100%;
  height: 6px;
  border-radius: 3px;
  background: #0d1b2a;
  outline: none;
  transition: var(--transition-smooth);
  border: 1px solid rgba(255,255,255,0.05);
}

.range-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--accent-cyan);
  cursor: pointer;
  box-shadow: 0 0 8px rgba(0, 245, 212, 0.8);
  transition: var(--transition-smooth);
}

.range-slider::-webkit-slider-thumb:hover {
  transform: scale(1.2);
  background: #fff;
  box-shadow: 0 0 12px rgba(255, 255, 255, 1);
}

/* ==========================================================================
   BIOLOGY 101 EXPLANATIONS SECTION
   ========================================================================== */
.tabs-header {
  display: flex;
  border-bottom: 2px solid rgba(255, 255, 255, 0.05);
  margin-bottom: 1.5rem;
}

.tab-btn {
  flex: 1;
  background: none;
  border: none;
  color: var(--text-secondary);
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  font-size: 1.05rem;
  padding: 0.75rem;
  cursor: pointer;
  transition: var(--transition-smooth);
  position: relative;
}

.tab-btn:hover {
  color: var(--text-primary);
}

.tab-btn.active {
  color: var(--accent-cyan);
}

.tab-btn.active::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--accent-cyan);
  box-shadow: var(--glow-cyan);
}

.tab-content {
  display: none;
  animation: fadeIn 0.4s ease forwards;
}

.tab-content.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.concept-card {
  background: rgba(255,255,255,0.02);
  border: 1px solid rgba(255,255,255,0.05);
  border-radius: var(--border-radius-sm);
  padding: 1.25rem;
  margin-bottom: 1.25rem;
  transition: var(--transition-smooth);
}

.concept-card:hover {
  background: rgba(255,255,255,0.04);
  border-color: rgba(255,255,255,0.1);
}

.concept-card h3 {
  font-size: 1.25rem;
  color: var(--accent-cyan);
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.biology-infotip {
  background: rgba(0, 187, 249, 0.08);
  border-left: 4px solid var(--accent-blue);
  padding: 1rem;
  border-radius: 0 var(--border-radius-sm) var(--border-radius-sm) 0;
  margin-top: 1rem;
  font-size: 0.95rem;
}

.biology-infotip p strong {
  color: var(--accent-blue);
}

/* ==========================================================================
   QUIZ COMPONENT
   ========================================================================== */
.quiz-container {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.question-text {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.options-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.option-btn {
  background: rgba(255,255,255,0.02);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: var(--border-radius-sm);
  padding: 1rem;
  text-align: left;
  color: var(--text-primary);
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition-smooth);
  position: relative;
  overflow: hidden;
}

.option-btn:hover {
  background: rgba(255,255,255,0.05);
  border-color: rgba(255,255,255,0.15);
}

.option-btn.correct {
  background: rgba(56, 176, 0, 0.15) !important;
  border-color: var(--accent-success) !important;
  color: #fff !important;
}

.option-btn.incorrect {
  background: rgba(255, 71, 126, 0.15) !important;
  border-color: var(--accent-danger) !important;
  color: #fff !important;
}

.quiz-feedback {
  padding: 1rem;
  border-radius: var(--border-radius-sm);
  font-size: 0.95rem;
  display: none;
  font-weight: 500;
  animation: fadeIn 0.3s ease;
}

.quiz-feedback.correct {
  display: block;
  background: rgba(56, 176, 0, 0.1);
  border: 1px solid rgba(56, 176, 0, 0.3);
  color: #a7f3d0;
}

.quiz-feedback.incorrect {
  display: block;
  background: rgba(255, 71, 126, 0.1);
  border: 1px solid rgba(255, 71, 126, 0.3);
  color: #fecdd3;
}

.quiz-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 1rem;
}

.btn-next {
  background: var(--grad-accent);
  border: none;
  color: #040914;
  padding: 0.75rem 1.5rem;
  border-radius: var(--border-radius-sm);
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition-smooth);
  box-shadow: var(--glow-blue);
}

.btn-next:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 20px rgba(0, 245, 212, 0.6);
}

.btn-next:disabled {
  background: rgba(255,255,255,0.05);
  color: var(--text-secondary);
  box-shadow: none;
  cursor: not-allowed;
  transform: none;
}

.score-panel {
  text-align: center;
  padding: 2rem 1rem;
}

.score-circle {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  border: 4px solid var(--accent-cyan);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  margin: 0 auto 1.5rem auto;
  box-shadow: var(--glow-cyan);
}

.score-num {
  font-size: 2.2rem;
  font-weight: 800;
  font-family: 'Outfit', sans-serif;
}

.score-total {
  font-size: 0.9rem;
  color: var(--text-secondary);
  border-top: 1px solid rgba(255,255,255,0.1);
  width: 60%;
  padding-top: 2px;
}

.btn-reset-quiz {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255,255,255,0.1);
  color: var(--text-primary);
  padding: 0.75rem 1.5rem;
  border-radius: var(--border-radius-sm);
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-smooth);
  margin-top: 1rem;
}

.btn-reset-quiz:hover {
  background: rgba(255, 255, 255, 0.1);
}

/* ==========================================================================
   MOLECULAR VIEW PANEL TOGGLE
   ========================================================================== */
.view-toggle-container {
  display: flex;
  background: rgba(255,255,255,0.03);
  border: 1px solid rgba(255,255,255,0.05);
  border-radius: var(--border-radius-sm);
  padding: 0.25rem;
}

.btn-view-toggle {
  flex: 1;
  background: none;
  border: none;
  color: var(--text-secondary);
  padding: 0.5rem;
  border-radius: 4px;
  cursor: pointer;
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  font-size: 0.9rem;
  transition: var(--transition-smooth);
}

.btn-view-toggle.active {
  background: rgba(0, 245, 212, 0.1);
  color: var(--accent-cyan);
  border: 1px solid rgba(0, 245, 212, 0.2);
}

.interactive-hint {
  font-size: 0.85rem;
  color: var(--text-secondary);
  text-align: center;
  margin-top: 0.5rem;
  font-style: italic;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.25rem;
}

.interactive-hint svg {
  color: var(--accent-blue);
}

/* ==========================================================================
   GLOSSARY & DETAILS LIST
   ========================================================================== */
.bullet-list {
  list-style: none;
}

.bullet-list li {
  position: relative;
  padding-left: 1.5rem;
  margin-bottom: 0.75rem;
}

.bullet-list li::before {
  content: '✦';
  position: absolute;
  left: 0;
  color: var(--accent-cyan);
}

.highlight {
  color: var(--accent-cyan);
  font-weight: 600;
}

.water-highlight {
  color: var(--accent-blue);
  font-weight: 600;
}

footer {
  text-align: center;
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid rgba(255,255,255,0.05);
  color: var(--text-secondary);
  font-size: 0.9rem;
}

footer a {
  color: var(--accent-cyan);
  text-decoration: none;
  transition: var(--transition-smooth);
}

footer a:hover {
  text-decoration: underline;
  color: #fff;
}