How do I Make Firefox Print a Background-Color Style?

Question

I have some simple CSS:

#someElement {
    background-color:black;
    color:white;
}

It looks ok in the browser, but when I go to print it

Answer 1

Maybe not the answer you're looking for, but here goes:

I'd rather add a separate stylesheet for printing the page. Typically, you would want to remove things like navigation menus, breadcrumbs, ads, and maybe do some small changes in margins, paddings, borders and fonts compared to the on-screen stylesheet.

Even thinking about forcing the user to fill a whole page with black ink with white text seems silly to me.

To add a separate print stylesheet, add another stylesheet to the head of your page.