Once the page navigation gets to the mobile breakpoint the arrows disappear (I wish there was a setting where we could control when this happens). I then set the flex direction to column and the link to 100%.
The problem is there is no way to set the flex direction on the next navigation element so it looks off as it is all right justified. I add in some custom css to fix this but in reality the widget should be doing this. BTW I have the image for the post navigation disabled.