nodes background gradient

[piranna]

I would like to know if it's possible to define a gradient color both in theme or raw CSS for the background of a node, instead of having just a plain color. SVG supports them but they need to be defined with SVG elements and later referenced, not just with the linear-gradient() function of HTML, that also fails due to the parenthesis. So, is there any way to define a linear gradient to fill a node background?