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

Yes

The word "amargo" is identical in spelling, meaning, and grammar in both Brazilian and Continental Portuguese. The only difference lies in pronunciation. In Brazilian Portuguese, vowels (especially unstressed ones) tend to be more open and clearly articulated. In Continental Portuguese, vowels are often more closed or "swallowed," meaning the "a" in "amargo" may sound much shorter and more neutralized to a Brazilian ear.

Brazilian Portuguese Examples:

1. Este café está muito amargo. (This coffee is very bitter.)
2. Ela guardou um sentimento amargo depois da briga. (She held onto a bitter feeling after the fight.)
3. Eu prefiro comer chocolate amargo. (I prefer to eat dark chocolate.)
4. Ele teve um amargo fim de carreira. (He had a bitter end to his career.)
5. A derrota deixou um gosto amargo para o time. (The defeat left a bitter taste for the team.)

Continental Portuguese Examples:

1. Este café está muito amargo. (This coffee is very bitter.)
2. Ela ficou com um sentimento amargo após a discussão. (She was left with a bitter feeling after the argument.)
3. Eu prefiro comer chocolate negro. (I prefer to eat dark chocolate.)
4. Teve um desfecho amargo para a sua carreira. (It had a bitter outcome for his career.)
5. A derrota deixou um sabor amargo. (The defeat left a bitter taste.)