Customizing HubSpot Form in WordPress

I am trying to customize a HubSpot form in our WordPress site. When I try to add custom css to the form advanced settings nothing is happening.

This is how the form currently looks https://drive.google.com/file/d/1LQQERUGwQUCS0SRicBoy3PxwCVOghuNy/view?usp=share_link

And this how I want the form to look. https://drive.google.com/file/d/1CoW0j6tFECzMW10w3pmTN1dTSO54KcuR/view?usp=share_link Could anyone assist me in where I would need to add the css to achieve this?

The page I need help with: [log in to see the link]