[QUESTION] Vertical panel buttons

Hi, I am trying to add vertical buttons in a panel. I have added a flexbox with a vertical direction, but since an additional div is added as an interim to the buttons, it does not affect them. Is there a way to solve this?

I have added the following code that does not appear to work ():

#files-container {
  padding: 0;
  height: 100%;
  width: 70px;
  display: flex;
  flex-flow: column wrap;
}

<div id="files-container"></div>
panels: {
        defaults: [ {
          id: 'files-picker',
          el: '#files-container',
          buttons: [{
            id: 'layer-picker',
            label: '<img src="assets/layers.svg">' 
          },{
            id: 'file-picker',
            label: '<img src="assets/files.svg">' 
          }]
        }
]}