To change the default site background color, navigate to your dashboard.
Next, select the Site Setup > Site Setup
Then click Site Background
Select the color your desire for your Site Background Color.
Hit the Update Button.
Go back to a page on your website and refresh your screen to see the changes. If you do not see the changes immediately take effect, clear your cache.
Important Note:
By changing the Site Background Color, it will change the default Site Background Color in the whole site. So, the blog posts, recipes, and all page site backgrounds will change too.