Make sure the AllowSelections property has the AlphaBlend flag included. Also set ListBoxSelectionMode to something other than None.
Then you should be able to sepecify the row selection color using teh grid.AlphaBlendSelectionColor property. You want want to include the A value you want as well.
To bold the text, you can handle the PrepareViewStyleInfo event.
private void gridControl1_PrepareViewStyleInfo(object sender, GridPrepareViewStyleInfoEventArgs e)
{
if(this.gridControl1.Selections.GetSelectedRows(true, false).AnyRangeContains(GridRangeInfo.Row(e.RowIndex)))
{
e.Style.Font.Bold = true;
}
}