Boxed Layout / margin colors

Hi,
I have a boxed design and I want to apply a color to the side margins created on both sides.
I tried changing the background color in the custom CSS. But apparently it doesn't apply to these margins.
Thanks for your help.

Ok, I got this.
I solved it this way (adding the last line below)
:root {
--cnvs-themecolor: #A83567;
--cnvs-themecolor-rgb: 168, 53, 103;
--cnvs-body-bg-boxed : #A83567;
}