Hello!
We intentionally don’t style what is inside of the flip box, we leave it open so that you can style it the way you want. I would suggest adding a div with a style that sets the padding. This is the simplest way to add padding. You could use an alert shortcode or something like that as well.
<div style="padding:10px;">
Your text here
</div>
If this doesn’t work or if you need additional help, please let us know.
Thanks!