How to scale radio buttons, checkboxes and captcha and button proportionally?

Dear Community, I have the following problem: I want to scale the fields on the page (https://herrpinguin.wixstudio.com/my-site-2 ) proportionally. Unfortunately, I can’t find a solution for how to do this. In the selection menu, there are only relative width and fixed.
I’m already starting to despair because I want the result to look like the picture on all sizes of computer screens.
Can someone help me with instructions? LG Mr. Penguin

It is a Wix Studio work for a Webside Projekt.