Pro Site CSS Styling

Hi, so I recently hired a "developer" design me a pretty smooth looking Pro Sites signup page and form.

However, I just switched themes and now it looks nothing like it did on the theme before, then though he used the CSS on the styling tab in Pro Sites.

Is this something I can fix, or you guys can check out, or will I have to hire him again?

https://citiera.com/pro-site/