I found this excerpt from Oxford Grammar Course:
In modern English, countries are most often it(s), though she/her is also common.
- Canada has decided to increase its/her trade with Russia.
Is the usage of determiner her in the sentence above can be used in formal English? Because, as far as I know, country is considered as a neutral noun and that's what Basic English Grammar books that I've studied usually write. Or is it some ungrammatical grammar, yet very common that becomes colloquial?