Thank you! I see the problem.
On the results page, there is an empty paragraph injected to the search, right before the button, so the CSS doesn’t apply properly. This usually happens the the search is placed into text module instead of a shortcode module (or not it’s own module).
Can you please check if you can replace that block with the ajax search pro search block? My guess is, that right now it might be a text block with the search shortcode or something similar.