Why do you strip quotes? Specifically, you're doing:
blockquote, q {
quotes: "" "";
}
and
blockquote::before, blockquote::after, q::before, q::after {
content: "";
}
You'd be better off completely removing this to begin with, as even if you did specify the quotes (which should only be on <q>, not <blockquote>, and it makes no sense to include <blockquote> in that rule anyways), you would have to re-define the quotes for every single language (q:lang(...)).
If this wasn't intentional, you should really pay attention to what your CSS reset does and make sure to explicitly define everything it resets.