Woops missed that in review, the correct invisible background-color value would be `background-color: transparent;` and not `background-color: none;` Alternatively, we can use `opacity: 0;` and `opacity: 1;` on hover.
Bug 1571349 Comment 6 Edit History
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Woops missed that in review, the correct invisible background-color value would be `background-color: transparent;` and not `background-color: none;` Alternatively, we can use `opacity: 0;` and `opacity: 1;` on hover. Tip: DevTools CSS is tested by the `browser/base/content/test/static/browser_parsable_css.js` test, which can be run with `./mach test browser_parsable_css` (not sure which test suite it's in).