Why does svg have a black background?

Question

css

Hello. Combined icons into one svg sprite, through symbol, into html I insert through svg > use. In chrome, everything is ok, but in firefox, some elements have a black background. What could be the reason for this and how to fix it?

Normal display of icons


Icons in firefox

Answer 1

Apparently, the elements do not have a background property, and by default Chrome assumes transparent, and Fox - black.
Fortunately, SVG is in such a format that you can open it in notepad and look at it.