Site Builder is no longer sold by Vista. This article is only relevant if you purchased a website from Vista before March 9, 2022.
If you're interested in purchasing a website, you can learn more at Vista x Wix.
Click Theme Styles > Theme Layout to adjust the position and width of your navigation header and website content.
When you choose Fixed Width, Left or Right for Content Position, the background colour is the theme default. You can change this by adjusting your Theme Background settings.
Remember to click Preview to see how your site will look on tablets and mobile phones. Depending on the content you add, some layouts may be more suited for mobile devices than others.