:root {
  --color-bg: #f8fafc;
  --color-surface: #ffffff;
  --color-border: #e2e8f0;
  --color-text: #1e293b;
  --color-text-muted: #64748b;
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-success: #16a34a;
  --color-success-hover: #15803d;
  --color-warning: #f59e0b;
  --color-error: #dc2626;
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --radius-sm: 4px;
  --radius-md: 8px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
  --font-family: system-ui, -apple-system, sans-serif;
}

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

body {
  font-family: var(--font-family);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.5;
}

.app-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: var(--spacing-md) var(--spacing-lg);
  text-align: center;
}

.app-header h1 {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: var(--spacing-xs);
}

.subtitle {
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

.app-main {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--spacing-lg);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: var(--spacing-lg);
}

.panel {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  box-shadow: var(--shadow);
}

.panel h2 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
  padding-bottom: var(--spacing-xs);
  border-bottom: 1px solid var(--color-border);
}

.upload-area {
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  text-align: center;
  transition: border-color 0.2s;
}

.upload-area.dragover {
  border-color: var(--color-primary);
  background: rgba(37, 99, 235, 0.05);
}

.upload-hint {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin-top: var(--spacing-sm);
}

.file-info {
  font-size: 0.85rem;
  color: var(--color-success);
  margin-top: var(--spacing-sm);
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-xs) var(--spacing-sm);
  border: none;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.2s, transform 0.1s;
}

.btn .icon {
  font-size: 1.1em;
}

.btn-primary {
  background: var(--color-primary);
  color: white;
}

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

.btn-secondary {
  background: var(--color-bg);
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover {
  background: var(--color-border);
}

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

.btn-success:hover {
  background: var(--color-success-hover);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-large {
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: 1rem;
}

.layers-container {
  max-height: 400px;
  overflow-y: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  margin-bottom: var(--spacing-sm);
}

.layer-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm);
  border-bottom: 1px solid var(--color-border);
}

.layer-item:last-child {
  border-bottom: none;
}

.layer-item input[type="checkbox"] {
  width: 18px;
  height: 18px;
  cursor: pointer;
}

.layer-name {
  flex: 1;
  font-size: 0.9rem;
  font-weight: 500;
}

.layer-depth {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.layer-depth label {
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.layer-depth input {
  width: 70px;
  padding: var(--spacing-xs);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
}

.layer-controls {
  display: flex;
  gap: var(--spacing-sm);
}

.settings-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--spacing-sm);
}

.setting-group {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

.setting-group label {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-text-muted);
}

.setting-group input,
.setting-group select {
  padding: var(--spacing-xs);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
}

.setting-group input:focus,
.setting-group select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.2);
}

.action-buttons {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.preview-container {
  min-height: 200px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-bg);
}

.preview-container svg {
  max-width: 100%;
  max-height: 300px;
}

.empty-state {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  text-align: center;
  padding: var(--spacing-lg);
}

.gcode-container {
  margin-bottom: var(--spacing-sm);
}

.gcode-container textarea {
  width: 100%;
  min-height: 200px;
  padding: var(--spacing-sm);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-family: 'Courier New', monospace;
  font-size: 0.85rem;
  line-height: 1.4;
  resize: vertical;
}

.gcode-stats {
  display: flex;
  gap: var(--spacing-md);
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.stat-item {
  display: flex;
  gap: var(--spacing-xs);
}

.stat-label {
  font-weight: 500;
}

@media (max-width: 768px) {
  .app-main {
    grid-template-columns: 1fr;
    padding: var(--spacing-sm);
  }

  .settings-grid {
    grid-template-columns: 1fr;
  }

  .layer-item {
    flex-wrap: wrap;
  }

  .layer-depth {
    width: 100%;
    margin-top: var(--spacing-xs);
  }
}