Forms do not currently allow a Stylesheet to be attached. However, you can edit the form HTML to add in CSS code if you wish.
- Navigate to Assets > Forms.
- Open your form.
- Click "CODE" on the right.
- Paste in CSS code.
Please understand that manually editing HTML code may result in a broken form or rendering issues if you are not an experienced HTML user. Engaging our Support or Design teams to fix a form problem with edited HTML code may be billable.