lative;
            border: 1px solid transparent;
            border-radius: 8px;
            transition: all 0.2s;
        }
        
        .cell:hover {
            border-color: var(--border-color);
        }
        
        .cell.selected {
            border-color: var(--accent-color);
            box-shadow: 0 0 0 1px var(--accent-color);
        }
        
        .cell.cell-running .execution-count {
            animation: pulse 1s infinite;
        }
        
        @keyframes pulse {
        