You can update the form colors to match your organization or logo colors as well as adjust the form width and choose your preferred font within the Form Colors/Visual Settings tool.
Once a form is published, you can edit the form colors/visual settings but going to your Published Forms
Select the Form Menu for the form you'd like to edit
Select Edit Form
Select to edit the Form Colors/Visual Settings
Adjust the colors, fonts, etc to your preference and then select Save My Changes
Note - If you add a header image to your form, the Form Table Width pixels should be equal to or greater than the pixel width of the header image - See the How to Add/edit a form Header Graphic article for more information.