Font Styling

[Myoldmopar]

Sorry to bombard with a few issues all at once; this library really has been a great way to add quick passcode session auth to a project I'm playing around on with my kids.

On mobile (iPhone 7 shown below), the buttons are nearly impossible to read. While we can obviously infer what they are since we know what a keypad looks like, it would be nice to add a quick little css tweak to the font size, or scale.

I may offer a pull request if you don't mind.