When using <CFChart>, in pie-chart style, you need to specify a ‘backgroundcolor’ attribute to set the background, not a ‘databackgroundcolor’ or ‘borderbackgroundcolor’ attribute as the documentation indicates. This is because borderbackgroundcolor has been deprecated and pie charts don’t have a data-background.
Why do I note this here? Because when I googled for ‘cfchart background color’, my own site was the first listed, and well, it didn’t have the answer I was looking for. Now, in the future when I forget this, it will be conveniently listed right here, for posterity.