When creating a HTML asset you have the option to keep the nav bar visible or hide it. To hide the nav bar choose full screen mode from the Asset Packager. Please note that you will need to tap on top of the page to get the nav bar back.
If you choose to keep the nav bar you will need to consider the slightly reduced screen size in nextINTERACT.
SmartPDF uses full screen when viewed, guidelines are as follows:
PORTRAIT: Height = 960 pixels/ 1024 pixels in full screen. Width = 758 pixels
LANDSCAPE: Height = 710 pixels/ 768 pixels in full screen. Width = 1024 pixels.