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

No

While the word "legal" retains its original meaning related to the law in both varieties of Portuguese (e.g., visto legal — legal visa), there is a major difference in its colloquial usage. In Brazilian Portuguese, "legal" is one of the most common slang terms used to mean "cool," "nice," "great," or "pleasant." In Continental Portuguese, using "legal" in this way is virtually non-existent; a Portuguese person would find it strange or interpret it strictly in a juridical context. To express the same sentiment, a person from Portugal would typically use words like fixe, bacano, or porreiro.

Brazilian Portuguese Examples (Colloquial usage)

1. Que filme legal! (What a cool movie!)
2. Ele é um cara muito legal. (He is a very nice guy.)
3. A festa de ontem foi muito legal. (Yesterday's party was very cool.)
4. Achei essa ideia muito legal. (I thought this idea was very good/cool.)
5. Legal, eu aceito o convite. (Cool, I accept the invitation.)

Continental Portuguese Examples (Equivalent usage)

1. Que filme fixe! (What a cool movie!)
2. Ele é um tipo muito porreiro. (He is a very nice/cool guy.)
3. A festa de ontem foi muito bacana. (Yesterday's party was very nice.)
4. Achei essa ideia muito boa. (I thought this idea was very good.)
5. Fixe, eu aceito o convite. (Cool, I accept the invitation.)