Is the word quais the same in Brazilian and European Portuguese?

Yes

The word "quais" is identical in meaning, spelling, and grammatical function in both Brazilian and Continental Portuguese. The only difference lies in pronunciation. In Brazilian Portuguese, the final "s" is typically pronounced as a sibilant [s] (similar to the 's' in "sun"), and the diphthong "ai" is usually more open and clear. In Continental Portuguese, the final "s" is often palatalized, sounding like [ʃ] (similar to the 'sh' in "shoe"), and the vowels may be more closed or reduced.

Brazilian Portuguese Examples

1. Quais são as suas cores favoritas? (Which are your favorite colors?)
2. Quais filmes você quer ver hoje? (Which movies do you want to see today?)
3. Quais são os seus planos para o fim de semana? (What are your plans for the weekend?)
4. Não sei quais livros comprar. (I don't know which books to buy.)
5. Quais são os ingredientes desta receita? (Which are the ingredients of this recipe?)

Continental Portuguese Examples

1. Quais são as tuas cores favoritas? (Which are your favorite colors?)
2. Quais filmes é que queres ver hoje? (Which movies do you want to see today?)
3. Quais são os teus planos para o fim de semana? (What are your plans for the weekend?)
4. Não sei quais os livros que devo comprar. (I don't know which the books are that I should buy.)
5. Quais são os ingredientes desta receita? (Which are the ingredients of this recipe?)