/* Core 9UY Utility Background */
:root {
  --bg: #0a0a0a;
  --bg-panel: rgba(23, 23, 23, 0.7);
  --fg: #9ca3af;
  --accent: #ffffff;
  --danger: #ef4444;
  --border: #262626;
  --border-hover: #404040;
  --text-muted: #6b7280;
}

body {
  overflow-x: hidden;
}

/* Custom Scrollbars */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

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

::-webkit-scrollbar-thumb:hover {
  background: #4b5563;
}

/* Tab Navigation */
.tab-btn {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  border-radius: 0.375rem;
  font-size: 0.625rem;
  text-transform: uppercase;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  transition: all 0.2s ease;
}

.tab-btn:hover {
  color: var(--accent);
  background: rgba(255, 255, 255, 0.05);
}

.tab-btn.active {
  color: #000;
  background: var(--accent);
}

/* Operation Toggle */
.op-btn {
  font-size: 0.625rem;
  text-transform: uppercase;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  padding: 0.25rem 0.75rem;
  border-radius: 0.25rem;
  transition: all 0.2s ease;
}

.op-btn.active {
  color: var(--accent);
  background: rgba(255, 255, 255, 0.1);
}

/* Pane Focus States */
#input-container:focus-within {
  border-color: var(--border-hover);
  background-color: var(--bg-panel);
}

#output-container {
  transition: border-color 0.3s ease, background-color 0.3s ease;
}

#output-container.highlight {
  border-color: var(--accent);
  background-color: rgba(255, 255, 255, 0.02);
}

/* Buttons */
button {
  outline: none;
}
button:focus-visible {
  box-shadow: 0 0 0 2px var(--border-hover);
}

/* Utility Animations */
@keyframes slideDown {
  from { opacity: 0; transform: translateY(-10px); }
  to { opacity: 1; transform: translateY(0); }
}

#output-error:not(.hidden) {
  display: flex;
  animation: slideDown 0.2s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}