I have some simple CSS:
#someElement {
background-color:black;
color:white;
}
It looks ok in the browser, but when I go to print it in Firefox it comes out as black text on a white background. I imagine this is some sort of ink-saving feature, but is there any way around it?
Its a browser setting. There is nothing you can do in your CSS. In Windows - File > Page Setup... > Print Background
.