Originally Posted by _savage
but font size is set through "small" or "larger" rather than pixel sizes.
Please don't tell us that you do what a lot of publishers do (wrongly) and use a font size of small? The best way to do it for most people is to not set a font size for the main body text and let the reading software use the default font size (most default to 1em).
The term larger is meaningless. It's x-small, small, large, x-large or xx-large.