I just updated to Brooklyn in my production org (I know… late to the party)… 
Since upgrading, my page layouts have changed slightly.
I have a page with a page background that is an image set to cover. It used to cover the whole visible page. Now there is a padding of 10 to 20px that I can’t get rid of.
I also had a separate semi-transparent background in my header that use to overlay the page background to make the header a little dimmer so the buttons would pop out more. The header background also has a 10px padding to it. 
Is this by design and can I decrease the padding?