Wearing dark clothes for christmas and/or new year

I live in sweden but have relatives in brazil. I will celebrate christmas and new year with them this year.

I mainly wear black and very dark/deep clothes. White and bright colors is just not something i usually enjoy or have in my wardrobe.

Being all 100% white during new year feels just a bit off for my personal taste but I could do it to respect the culture, or at least have a white T-shirt.

But I'm wondering - will it be disrespectful if I wear a black shirt during new year?

Alternatively, will a black shirt at least during Christmas be ok?

Trying to find a compromise where I can be myself, but still don't show too much disrespect.

Thanks!