In Firefox, active box-shadow causes rendering artifacts

[jhung]

Describe the bug

In Firefox, the active box-shadow causes rendering artifacts to appear, making the box shadow appear different widths. This may be the cause of both a border being rendered along with the box-shadow, or part of the box-shadow being inset and part being outset.

This is not a problem for Chromium browsers.

Screenshots

Firefox:

Edge / Chrome:

Additional Context

This is likely caused by a combination of a border being applied with a box shadow. Firefox's rendering of these two styles simultaneously often causes visual artifacts.