Hello Ryan - @bowtiekreative !

If you don't have the access to the code then you have the following tools for that:

1) Studio->Designer->Injections area where you may add the HTML / CSS / JS code for the whole site. See more info here

2) Studio->Artificer->Styles area to put own CSS code for the whole site

3) Studio-->Pages app where you may add own HTML / CSS / JS code via the RAW / HTML blocks for the certain pages. See more details here

The form itself can be modified via the Studio->Forms app.