How can I have the font size in the form to be 12pt?

I'm trying to get my fonts all the same size. I've set the base size to 15pt in the designer. And in the text boxes I use 12pt. But the other elements (e.g. a tickbox - below) are smaller. How can I align everything to be the size of the 12pt text?

I'm also confused about the base font being 15pt and the in-text-box font being 12pt. Because the 12pt is the biggest font on the survey currently.

Hello,

The font size in the designer is in PX, not pt. Your current font size is set to 16px which is not the same for the entire form unless you want to include the sizes of the header elements.

The Multiple Choice font size is also 16px, it is the same as other fields. 

If you want to adjust the overall font size, you can use * (asterisk) selector. Example:

* {

    font-size: 12pt !important;

}