Text scaling
Josh Tumath in Try text scaling support in Chrome Canary:
Tip 1: Don't override the initial font size
The default font size comes from the initial value of the CSS font-size property. If an author doesn't specify a size, the initial font-size is medium. But what is medium? Typically it's 16px. But on desktop browsers, users can change it to whatever they want.
Came across this about text scaling, which is definitely a much needed feature, via Luke Harris. Josh's post is clear with good advice on how to support text scaling on your website. I have a ways to go, and need to dive into my CSS to fix it.
Ironically, I've only overridden the initial font size on my site here because I find initial font size to be too small!