Author your deck at a fixed virtual resolution and have it scale to fit any screen, so layouts stay pixel-consistent regardless of the display.
Add data-resolution="WIDTH HEIGHT" to the <body> (for the whole deck), a grouping element, or an individual slide:
<body data-resolution="1024 768">The page is zoomed to fit the viewport while preserving the aspect ratio, and re-adjusts on resize. Slides outside any [data-resolution] render normally.
Autoloads when any [data-resolution] element is present.