This.

There can be local differences in the dress code as long as it’s considered modest in the local culture (عُرْف, ie. convention or norm) and it does not show what has to be covered as part of a woman’s عَوْرَة (en.wikipedia.org/wiki/Intimate_parts_in_Islam).

So in some areas it is socially acceptable to have colours while in others the norm is all black.