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

No.

While the primary meanings of "risco"—such as "danger/risk," "a single line," or "a scratch"—are identical in both Brazilian and Continental Portuguese, there is a difference in typical usage regarding patterns. In Brazil, "risco" can be used to describe a stripe or a linear pattern on fabric (though "listra" is also common). In Portugal, the word "risco" is strictly used for a single line or scratch; when referring to stripes on clothing, a Portuguese person will almost exclusively use the word "riscas."

Brazilian Portuguese Examples

1. Você está correndo um risco muito grande. (You are running a very large risk.)
2. Eu fiz um risco no papel para marcar o lugar. (I made a line on the paper to mark the place.) Note: In Brazil, "celular" and "tela" are the standard terms.
3. O celular caiu e ficou com um risco na tela. (The cell phone fell and ended up with a scratch on the screen.)
4. Não vale a pena assumir esse risco. (It is not worth taking this risk.)
5. Eu gosto de camisas com risco. (I like shirts with stripes/lines.)

European Portuguese Examples

1. Estás a correr um risco muito grande. (You are running a very large risk.)
2. Eu fiz um risco no papel para marcar o lugar. (I made a line on the paper to mark the place.) Note: In Portugal, "telemóvel" and "ecrã" are the standard terms.
3. O telemóvel caiu e ficou com um risco no ecrã. (The mobile phone fell and ended up with a scratch on the screen.)
4. Não vale a pena assumir esse risco. (It is not worth taking this risk.)
5. Eu gosto de camisas com riscas. (I like shirts with stripes.)