A theme is a combination of a background and default color set, fonts, icons, and other design elements.
To change your project's theme:
❶ Deselect any objects in your project or click outside of the canvas.
❷ Open the Settings tab in the right sidebar, then click on the thumbnail to toggle to a different theme. This will change chart and text field colors, the font type, and in most cases - also the background color.
Note: the charts and objects visible in the thumbnails are just illustrations for chart and background color combinations, you can create any type of chart within any theme.
❸ To customize the background color, click the colored square below the theme selector, under Project background. You can do that even after choosing the theme.
Note: Changing the background color code will be possible in template project types only (this option is not available in chart and map project types).