You can easily fix it by using CSS:
h1 { color: red; font-size: 130%; }
In this case, the different in "h1" font size in "section" will be ignored. To make sized different, but your own, use
h1 { color: red; font-size: 120%; }
section h1 { color: red; font-size: 160%; }
Many use the following trick: to make all rendering very close with all different cases, with different browsers/platforms, do the following: create so called "reset CSS" and apply it to each and every HTML page, to bring
rendering engines to some "common denominator". On top of it, specific CSS are developed. See, in particular,
CSS Reset | 2015's most common CSS Resets to copy/paste, with documentation / tutorials[
^].
—SA