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

No.

While the spelling and core meaning of "esconder" are identical in both varieties, the grammar and typical usage surrounding the word differ significantly. In Brazil, the gerund (escondendo) is the standard way to express ongoing actions, and reflexive pronouns typically precede the verb (se esconder). In Portugal, the "a + infinitive" construction (a esconder) is used for ongoing actions, and reflexive pronouns are typically attached to the end of the verb (esconder-se).

Brazilian Portuguese Usage

1. Eu estou escondendo o presente debaixo da cama. (I am hiding the gift under the bed.)
2. Ela se escondeu atrás da cortina. (She hid herself behind the curtain.)
3. Não se esconda de mim. (Don't hide from me.)
4. As crianças estão se escondendo no quintal. (The children are hiding in the backyard.)
5. Ele escondeu o dinheiro no cofre. (He hid the money in the safe.)

Continental Portuguese Usage

1. Eu estou a esconder o presente debaixo da cama. (I am hiding the gift under the bed.)
2. Ela escondeu-se atrás da cortina. (She hid herself behind the curtain.)
3. Não te escondas de mim. (Don't hide from me.)
4. As crianças estão a esconder-se no quintal. (The children are hiding in the backyard.)
5. Ele escondeu o dinheiro no cofre. (He hid the money in the safe.)