UGUI: make grid scrollbar size bigger

Our users requested to make the scrollbars a bit bigger in the Universal GUI. Is there a way to change this?

I have tried the following custom css, but I was only able to change the form scrollbar. The grid scrollbar remains unaffected.

::-webkit-scrollbar {
  width: 20px !important;
  height: 20px !important;
}


.ag-body-vertical-scroll,
.ag-body-vertical-scroll-viewport,
.ag-body-vertical-scroll-container {
  width: 20px !important;
  min-width: 20px !important;
  max-width: 20px !important;
}

.ag-body-horizontal-scroll,
.ag-body-horizontal-scroll-viewport,
.ag-body-horizontal-scroll-container {
  height: 20px !important;
  min-height: 20px !important;
  max-height: 20px !important;
}