:root {
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-error: #ef4444;
  --color-bg: #0f172a;
  --color-bg-secondary: #1e293b;
  --color-bg-tertiary: #334155;
  --color-text: #f1f5f9;
  --color-text-secondary: #cbd5e1;
  --color-text-muted: #64748b;
  --color-border: #475569;
  --color-border-focus: var(--color-primary);
  
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  line-height: 1.6;
  font-weight: 400;
  color: var(--color-text);
  background-color: var(--color-bg);
  
  font-synthesis: none;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: linear-gradient(135deg, var(--color-bg) 0%, #1a202c 100%);
}

#app {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.header {
  text-align: center;
  padding: 2rem 1rem;
  background: var(--color-bg-secondary);
  border-bottom: 1px solid var(--color-border);
}

.header h1 {
  font-size: 2.5rem;
  font-weight: 700;
  margin: 0 0 0.5rem 0;
  background: linear-gradient(135deg, var(--color-primary), var(--color-success));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.header p {
  font-size: 1.1rem;
  color: var(--color-text-secondary);
  margin: 0;
}

.main-content {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  padding: 2rem;
  max-width: 1400px;
  margin: 0 auto;
  width: 100%;
}

.input-section, .output-section {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

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

.control-group label {
  font-weight: 500;
  color: var(--color-text);
  font-size: 0.9rem;
}

.control-group label[for="exclude-common"] {
  flex-direction: row;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
}

.control-group input[type="text"] {
  padding: 0.75rem 1rem;
  border: 2px solid var(--color-border);
  border-radius: 8px;
  background: var(--color-bg-secondary);
  color: var(--color-text);
  font-size: 1rem;
  transition: all 0.2s ease;
}

.control-group input[type="text"]:focus {
  outline: none;
  border-color: var(--color-border-focus);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.control-group input[type="checkbox"] {
  width: 1.1rem;
  height: 1.1rem;
  accent-color: var(--color-primary);
}

.textarea-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  flex: 1;
}

.textarea-group label {
  font-weight: 500;
  color: var(--color-text);
  font-size: 0.9rem;
}

.textarea-group textarea {
  flex: 1;
  padding: 1rem;
  border: 2px solid var(--color-border);
  border-radius: 8px;
  background: var(--color-bg-secondary);
  color: var(--color-text);
  font-family: 'JetBrains Mono', 'Fira Code', monospace;
  font-size: 0.9rem;
  line-height: 1.5;
  resize: vertical;
  min-height: 300px;
  transition: all 0.2s ease;
}

.textarea-group textarea:focus {
  outline: none;
  border-color: var(--color-border-focus);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.textarea-group textarea::placeholder {
  color: var(--color-text-muted);
}

.textarea-group textarea[readonly] {
  background: var(--color-bg-tertiary);
  cursor: default;
}

.transform-btn {
  padding: 0.875rem 2rem;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  text-transform: uppercase;
  letter-spacing: 0.025em;
}

.transform-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

.transform-btn:active {
  transform: translateY(0);
}

.output-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.output-header label {
  font-weight: 500;
  color: var(--color-text);
  font-size: 0.9rem;
}

.copy-btn {
  padding: 0.5rem 1rem;
  background: var(--color-success);
  color: white;
  border: none;
  border-radius: 6px;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
  opacity: 0.7;
}

.copy-btn:disabled {
  background: var(--color-text-muted);
  cursor: not-allowed;
  opacity: 0.5;
}

.copy-btn:not(:disabled):hover {
  background: #059669;
  transform: translateY(-1px);
  opacity: 1;
}

.copy-btn.copied {
  background: var(--color-warning);
}

.stats {
  padding: 1rem;
  background: var(--color-bg-tertiary);
  border-radius: 6px;
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  border-left: 3px solid var(--color-success);
}

.footer {
  text-align: center;
  padding: 1.5rem;
  border-top: 1px solid var(--color-border);
  background: var(--color-bg-secondary);
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 1024px) {
  .main-content {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
  
  .header h1 {
    font-size: 2rem;
  }
}

@media (max-width: 768px) {
  .main-content {
    padding: 1rem;
  }
  
  .header {
    padding: 1.5rem 1rem;
  }
  
  .header h1 {
    font-size: 1.75rem;
  }
  
  .output-header {
    flex-direction: column;
    align-items: stretch;
    gap: 0.75rem;
  }
  
  .textarea-group textarea {
    min-height: 250px;
  }
}

/* Scrollbar Styling */
textarea::-webkit-scrollbar {
  width: 8px;
}

textarea::-webkit-scrollbar-track {
  background: var(--color-bg);
}

textarea::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: 4px;
}

textarea::-webkit-scrollbar-thumb:hover {
  background: var(--color-text-muted);
}