Thanks Steve and Matt! This info was super helpful. What I ended up doing was creating and approving the landing page with the form as I normally would. I then copied the page source and pasted it into a new landing page template. Inside the template, I altered the style of text for the form fields and customized the line spacing.
Then in our program, I just created a new landing page with this template and approved - it works perfectly! The only thing is that the landing page summary doesn't record when a form is filled out, so our landing page performance report will be inaccurate. However, we are using a progression status change flow in the program to record when the form is filled out, and that is working just fine to record form conversions.