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

Yes

The difference is purely phonetic. In Brazilian Portuguese, vowels are generally more open and clearly articulated, and the rhythm of speech is more melodic. In Continental Portuguese, unstressed vowels—specifically the final "a" in "amarela"—tend to be more closed or even reduced, which can make the word sound much more "clipped" or swallowed compared to the Brazilian pronunciation.

Brazilian Portuguese

1. Eu comprei uma blusa amarela. (I bought a yellow blouse.)
2. Minha caneta amarela sumiu. (My yellow pen disappeared.)
3. O ônibus amarelo é novo. (The yellow bus is new.)
4. Essa cor amarela é muito legal. (This yellow color is very cool.)
5. Vi um trem amarelo. (I saw a yellow train.)

Continental Portuguese

1. Eu comprei uma camisola amarela. (I bought a yellow sweater.)
2. A minha caneta amarela desapareceu. (My yellow pen disappeared.)
3. O autocarro amarelo é novo. (The yellow bus is new.)
4. Essa cor amarela é muito fixe. (This yellow color is very cool.)
5. Vi um comboio amarelo. (I saw a yellow train.)