Slickgrid - Cell CSS Changes

HTML

<link rel="stylesheet" href="http://mleibman.github.io/SlickGrid/slick.grid.css">
<script src="http://mleibman.github.io/SlickGrid/lib/jquery.event.drag-2.2.js"></script>
<script src="http://mleibman.github.io/SlickGrid/slick.core.js"></script>
<script src="http://mleibman.github.io/SlickGrid/slick.grid.js"></script>
<script src="http://mleibman.github.io/SlickGrid/slick.dataview.js"></script>
<div id="myGrid" style="width:100%;height:500px;"></div>

CSS

.my_highlighter_style {
      background: pink;
    }

JavaScript

var grid;
 var data = [];
 var columns = [
    {id: "server", name: "Server", field: "server", width: 180}
  ];
   
 for (var i = 0; i < 4; i++) {
    columns.push({
      id: "id" + i,
      name: "Id" + i,
      field: i
    });
  }

  var options = {
    editable: false,
    enableAddRow: false,
    enableCellNavigation: true
  };


  $(function () {
    for (var i = 0; i < 5; i++) {
      var d = (data[i] = {});
      d.server = "Server " + i;
      for (var j = 0; j < columns.length; j++) {
        d[j] = Math.round(Math.random() * 100);
      }
    }

    grid = new Slick.Grid("#myGrid", data, columns, options);

      grid.onMouseEnter.subscribe(function(e, args){
        var cell = grid.getCellFromEvent(e),
            param = {},
            columnCss = {};
          
          for(index in columns){
              var id = columns[index].id;
              columnCss[id] = 'my_highlighter_style'
          }
          param[cell.row] = columnCss
          args.grid.setCellCssStyles("row_highlighter", param);
      })
      
        grid.onMouseLeave.subscribe(function(){
         console.log("Still firing")
      })
  });