Assigning classes to embed code

Hi,

I’m in the process of switching from MailChimp to Drip for my email marketing. I figured out how to get the form to style for MailChimp, but the embed code for Drip doesn’t work the same. (I don’t have a background in manually coding.) Here’s a video I made regarding this:

YouTube Video of the Issue

Here’s the read-only link to the project:

Read-Only Link

Thanks in advance for any assistance!