notebook-toolbar {
            position: sticky;
            top: 0;
            z-index: 100;
            background: var(--toolbar-background);
            border-bottom: 1px solid var(--border-color);
            padding: 8px 16px;
            display: flex;
            align-items: center;
            gap: 16px;
            box-shadow: 0 1px 3px rgba(0,0,0,0.05);
        }
        
        .toolbar-group {
            display: flex;
            gap: 4px;
            align-items: center;
        }
      