We don't have a way to change the color of your page's background at this time, but it is a feature we're working on, along with other page customization options! If you ventured to the Page Settings and found the custom color section, this is where you can add a custom color to your options of colors which you can use on select content tiles. With Links and Files, you can select a color for this piece of content on your page. Sadly this will not offer any option to change the color of the background of your page.