In the sidebar block of the editor page you can find the background settings. Here you can set the canvas and its background according to your needs.

How to set the background colour

In the background settings you can select the most appropriate background colour for the canvas. Please enter the HEX colour code or simply click on the colour preview box and select the desired one.  

How to set the background image

You can upload an image from your computer to use as a background image in your visualization. 
Supported file formats: .gif, .jpg, .png
Maximum file size: 2 Mb
The background image will be resized dinamically in order to fit perfectly on your canvas.

How to set the canvas size

You can adjust your canvas size according to the screen size of the target device. You can enter pixel or aspect ratio, it is up to you.
If the visualisation is watched on a device with different aspect ratio or resolution, the aspect ratio that you have added will be maintaned and the rest of the screen filled with the selected background colour.