You have a number of options when customizing the look of your GrazeCart site. You can add your own branding by uploading your logo, change the colors, fonts, layout of your header, and more.
To edit your Site theme go to My Site / Theme.
When customizing your site use the left-hand panel to view the various theme settings, such as your colors and logo, and for editing the different settings for each theme element. On the right is a live preview of your site so you can see all the changes in real-time. Once you are satisfied with how things look, click the save button to make those changes live for your customers.
Checkout these GrazeCart sites for a bit of design inspiration: