You can access the styling settings by clicking the wheel icon on the left. The first tab of the Website Settings is the Styling.
You can style the main website layout ( Full-Width or Boxed ). If you select Boxed you can add or select a pattern that will be the background for the sides of the website like on the picture below.
You can select Pirmary Color that is going to be the brand color for your website on certain places like - header, sliders, blog buttons etc. Background Color on the other hand is the main color for all pages background (most of the time in white or very light color by default).
Last but not least is the Font Import that allows you to add new fonts to your website. You can select out of few hundred amazing google fonts fitting any need, they will be show in your text editor and everywhere you can select a font. You can add 4 custom fonts to keep your website fast and light.