How to adjust the size of individual RadioButtonList buttons

[Guest]

Excuse me if this is a beginner's question but I have never worked with the
RadioButtonList before and I'm having a little trouble finding info about
customizing it.

What I would like to do is either:
1. Set the width and height of the individual buttons in code.
2. Set default values in the main CSS script.

So far nothing has worked (and as usual I'm in a bit too much of a hurry).

Thanks.