How do I reduce lineHeight for rows with subRows?

[DKGH]

I want to reduce line height to 12px. However, I can only do this for rows without subrows. Those with subrows look taller. Their height cannot be reduced beyond ~24px. I am attempting this as below:

mantineTableBodyRowProps: ({row} : { row: MRT_Row<RowType> }) => ({
  style: {
    lineHeight: '12px', padding: '0px',
  }
});

Going by the following, I can see that those with display: 'none' can be shortened and those with display: 'block' cannot. I've tried changing the button size as below, but it does not appear to do anything:

mantineExpandButtonProps: ({row} : { row: MRT_Row<RowType> }) => ({
  style: {
    display: row.getCanExpand() ? 'block' : 'none',
    size: '12px',
    padding: '0px',
  }
)};