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

No

While the spelling, meaning, and grammatical identity of "estava" (the first and third-person singular imperfect indicative of the verb estar) are identical in both dialects, the typical usage and pronunciation differ:

• Usage (Syntax): In Brazil, "estava" is typically used with the gerund to express ongoing actions (e.g., estava fazendo). In Portugal, "estava" is almost exclusively used with the preposition "a" followed by the infinitive (e.g., estava a fazer).
• Pronunciation: In Brazilian Portuguese, the vowels are generally more open and clearly articulated. In Continental Portuguese, unstressed vowels are often "reduced" or swallowed, making the word sound more clipped or subtle.

Brazilian Portuguese Examples

1. Eu estava estudando muito para a prova. (I was studying a lot for the exam.)
2. Ela estava muito feliz com o presente. (She was very happy with the gift.)
3. O dia estava muito quente ontem. (The day was very hot yesterday.)
4. A gente estava conversando no shopping. (We were chatting at the mall.)
5. O cachorro estava correndo no parque. (The dog was running in the park.)

Continental Portuguese Examples

1. Eu estava a estudar muito para o exame. (I was studying a lot for the exam.)
2. Ela estava muito contente com o presente. (She was very happy with the gift.)
3. O dia estava muito quente ontem. (The day was very hot yesterday.)
4. Nós estávamos a conversar no centro comercial. (We were chatting at the shopping center.)
5. O cão estava a correr no parque. (The dog was running in the park.)