How to make outset/inset stroke in inkscape?

Question

I am trying to create SVG GUI item. Something like this:

It has two inset borders. I don't even know how to force rectangle to have an inset border. How do I do that?

Answer 1

The solution is to use gradients. By placing two gradient stops at the same location, you achieve the sharp switch:

This is the result:

Nest step is to turn the gradient ton 45°. I simply zoom in to put the gradient begin and and as close to the corner as possible:

And here's the result, nice simple inset border: