How do I change the colors, fonts, logo, and other styles of an Inquiry?

To explore and edit the visual design of an Inquiry including the colors, buttons, fonts, and more navigate to Inquiries → Themes. Once you're done making your changes, remember to save them.

Theme Sets are global and so you'll have to set them on the specific Inquiry Templates that where you'd like it applied. Many customers use Theme Sets to apply different a different look and feel to their business units, parts of the user experience, and more. To apply your changes to a specific Inquiry Template navigate to Inquiries → Templates → Select the Inquiry Template where you'd like the theme to be applied. From there click Configure in the top-right corner of your screen and click Replace to choose the theme set you'd like to apply to the template. Don't forget to save and publish your Inquiry template changes.

Read the more complete guide on Theme Sets for more information.