Full Width Check Box Fields?

I have a single checkbox and I set width to 100% but it is still only taking up half the space, with text wrapping to the next line. Is there a way to have it take up the full width?

You can see it here: https://podohub.com/shop/shoe-lasts/womens-shoe-lasts/addis-womens-shoe-last/

The text is “Include 3D Model (stl format) (+$20.00 USD)”
which I’d prefer to only take up one line but it takes up two.

Thanks,
Sam