Is an abaya that contains buttons in a particular way considered an adornment in itself, and what if its color differs from the color of the niqab?

The condition for the hijab is that it should not be an adornment in itself. If the buttons are an adornment that attracts attention, then they are (prohibited). However, a mere difference in the color of the buttons or the niqab is not considered an adornment unless it attracts attention. One should be cautious of excessive scrupulosity (waswasa) in these matters.