In Survalyzer there is a survey layout designer feature as seen in the following screenshot:

It is not available to all users by default, it needs to be requested and turned on for specific users by Survalyzer team.
Read more here about receiving access to Layout Designers.
Changes possible to make with survey layout editor settings
Survey Layout Editor is very extensive and allows to control almost every aspect of the survey appearance with simple sidebar settings. Among others:
- Survey layout header / footer / progress bar / language selector
- Texts font / color / size / spacing / headers structure
- Buttons and containers backgrounds and borders, including colors / radius / line width
- Favicon
- Survey browser page title
For all requirements not possible to achieve with simple sidebar settings, we offer custom CSS code input for full visual control
