In New W3C website launched I mentioned that the W3C’s new site uses a bit of invalid CSS. A couple of readers have told me that the errors caused by vendor-specific extensions aren’t really errors, and that the CSS validator is wrong to report such property names as errors.
I wasn’t completely sure about whether or not this was true, so I did a bit of research. And, to the best of my understanding, vendor-specific extensions are invalid.
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