* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --primary-color: #3b82f6;
  --secondary-color: #1e40af;
  --accent-color: #f59e0b;
  --success-color: #10b981;
  --danger-color: #ef4444;
  --warning-color: #f59e0b;
  --background-dark: #0f172a;
  --background-light: #1e293b;
  --background-card: #334155;
  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --border-color: #334155;
  --bar-default: #3b82f6;
  --bar-comparing: #fbbf24;
  --bar-swapping: #ef4444;
  --bar-sorted: #10b981;
  --bar-found: #84cc16;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, var(--background-dark) 0%, var(--background-light) 100%);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
}

.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 2rem;
}

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

header h1 {
  font-size: 3rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 0.5rem;
}

header p {
  font-size: 1.2rem;
  color: var(--text-secondary);
}

.input-section {
  background: var(--background-light);
  border-radius: 16px;
  padding: 2rem;
  margin-bottom: 2rem;
  border: 1px solid var(--border-color);
}

.input-group {
  display: flex;
  gap: 1rem;
  align-items: end;
  margin-bottom: 2rem;
  flex-wrap: wrap;
}

.input-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.input-group input {
  flex: 1;
  min-width: 300px;
  padding: 0.875rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  background: var(--background-dark);
  color: var(--text-primary);
  font-size: 1rem;
  transition: border-color 0.3s ease;
}

.input-group input:focus {
  outline: none;
  border-color: var(--primary-color);
}

.controls-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  margin-bottom: 2rem;
}

.control-group {
  background: var(--background-dark);
  padding: 1.5rem;
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.control-group h3 {
  margin-bottom: 1rem;
  color: var(--primary-color);
  font-size: 1.2rem;
}

.control-group select,
.control-group input {
  width: 100%;
  padding: 0.75rem;
  margin-bottom: 1rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  background: var(--background-light);
  color: var(--text-primary);
  font-size: 1rem;
}

.control-group select:focus,
.control-group input:focus {
  outline: none;
  border-color: var(--primary-color);
}

.control-group optgroup {
  font-weight: bold;
  color: var(--text-secondary);
}

.control-group option {
  padding: 0.5rem;
  background: var(--background-light);
  color: var(--text-primary);
}

button {
  padding: 0.875rem 1.5rem;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s ease;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.primary-btn {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: white;
  width: 100%;
}

.primary-btn:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(59, 130, 246, 0.3);
}

.primary-btn:disabled {
  background: var(--border-color);
  cursor: not-allowed;
  transform: none;
}

.action-controls {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

.action-controls button {
  min-width: 120px;
}

#generate-random {
  background: var(--accent-color);
  color: white;
  white-space: nowrap;
}

#generate-random:hover {
  background: #d97706;
  transform: translateY(-2px);
}

#reset-btn {
  background: var(--warning-color);
  color: white;
}

#reset-btn:hover {
  background: #d97706;
  transform: translateY(-2px);
}

#stop-btn {
  background: var(--danger-color);
  color: white;
}

#stop-btn:hover:not(:disabled) {
  background: #dc2626;
  transform: translateY(-2px);
}

/* Algorithm Info Section */
.algorithm-info-section {
  background: var(--background-light);
  border-radius: 16px;
  padding: 2rem;
  margin-bottom: 2rem;
  border: 1px solid var(--border-color);
}

.algorithm-details h3 {
  color: var(--primary-color);
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

.algorithm-details p {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  line-height: 1.7;
}

.complexity-info {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
}

.complexity-item {
  background: var(--background-dark);
  padding: 1rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.complexity-label {
  color: var(--text-muted);
  font-weight: 500;
}

.complexity-item span:last-child {
  color: var(--accent-color);
  font-weight: 600;
  font-family: 'Courier New', monospace;
}

.visualization-section {
  background: var(--background-light);
  border-radius: 16px;
  padding: 2rem;
  border: 1px solid var(--border-color);
}

.algorithm-info {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.algorithm-info h3 {
  font-size: 1.5rem;
  color: var(--primary-color);
}

.stats {
  display: flex;
  gap: 2rem;
  font-size: 1rem;
  color: var(--text-secondary);
}

.stats span {
  padding: 0.5rem 1rem;
  background: var(--background-dark);
  border-radius: 6px;
  border: 1px solid var(--border-color);
}

.visualization-container {
  background: var(--background-dark);
  border-radius: 12px;
  padding: 2rem;
  min-height: 400px;
  margin-bottom: 2rem;
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
}

#array-container {
  display: flex;
  align-items: end;
  justify-content: center;
  gap: 4px;
  width: 100%;
  height: 300px;
  flex-wrap: wrap;
}

.array-bar {
  background: var(--bar-default);
  border-radius: 4px 4px 0 0;
  display: flex;
  align-items: end;
  justify-content: center;
  color: white;
  font-weight: 600;
  font-size: 0.9rem;
  transition: all 0.3s ease;
  min-width: 40px;
  position: relative;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.array-bar:hover {
  transform: scale(1.05);
}

.array-bar.comparing {
  background: var(--bar-comparing);
  transform: scale(1.1);
  box-shadow: 0 4px 16px rgba(251, 191, 36, 0.4);
}

.array-bar.swapping {
  background: var(--bar-swapping);
  transform: scale(1.15);
  box-shadow: 0 6px 20px rgba(239, 68, 68, 0.4);
}

.array-bar.sorted {
  background: var(--bar-sorted);
  box-shadow: 0 4px 16px rgba(16, 185, 129, 0.3);
}

.array-bar.found {
  background: var(--bar-found);
  transform: scale(1.2);
  box-shadow: 0 8px 25px rgba(132, 204, 22, 0.5);
  animation: pulse 1s infinite;
}

@keyframes pulse {
  0%, 100% { transform: scale(1.2); }
  50% { transform: scale(1.3); }
}

.array-bar span {
  position: absolute;
  bottom: 8px;
  font-size: 0.8rem;
}

.legend {
  display: flex;
  justify-content: center;
  gap: 2rem;
  flex-wrap: wrap;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.legend-color {
  width: 20px;
  height: 20px;
  border-radius: 4px;
  border: 1px solid var(--border-color);
}

.legend-color.default { background: var(--bar-default); }
.legend-color.comparing { background: var(--bar-comparing); }
.legend-color.swapping { background: var(--bar-swapping); }
.legend-color.sorted { background: var(--bar-sorted); }
.legend-color.found { background: var(--bar-found); }

/* Message Styles */
.message {
  padding: 1rem;
  border-radius: 8px;
  margin: 1rem 0;
  text-align: center;
  font-weight: 500;
  animation: slideIn 0.3s ease-out;
}

.success-message {
  background: var(--success-color);
  color: white;
}

.error-message {
  background: var(--danger-color);
  color: white;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateY(-20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Responsive Design */
@media (max-width: 768px) {
  .container {
    padding: 1rem;
  }
  
  header h1 {
    font-size: 2rem;
  }
  
  .input-group {
    flex-direction: column;
    align-items: stretch;
  }
  
  .input-group input {
    min-width: auto;
  }
  
  .controls-grid {
    grid-template-columns: 1fr;
  }
  
  .algorithm-info {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }
  
  .stats {
    flex-direction: column;
    gap: 0.5rem;
  }
  
  .complexity-info {
    grid-template-columns: 1fr;
  }
  
  #array-container {
    height: 250px;
  }
  
  .array-bar {
    min-width: 30px;
    font-size: 0.8rem;
  }
  
  .legend {
    gap: 1rem;
  }
}

@media (max-width: 480px) {
  .input-section,
  .visualization-section,
  .algorithm-info-section {
    padding: 1rem;
  }
  
  .control-group {
    padding: 1rem;
  }
  
  .visualization-container {
    padding: 1rem;
  }
  
  #array-container {
    height: 200px;
    gap: 2px;
  }
  
  .array-bar {
    min-width: 25px;
    font-size: 0.7rem;
  }
}

/* Loading Animation */
.loading {
  opacity: 0.7;
  pointer-events: none;
}

/* Error States */
.input-error {
  border-color: var(--danger-color) !important;
  animation: shake 0.5s ease-in-out;
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-5px); }
  75% { transform: translateX(5px); }
}

/* Enhanced Visual Effects */
.algorithm-info-section {
  background: linear-gradient(135deg, var(--background-light) 0%, var(--background-card) 100%);
}

.complexity-item:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

/* Smooth transitions for all interactive elements */
* {
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

/* Focus styles for accessibility */
button:focus,
input:focus,
select:focus {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}