The detail that would create the BEST example of juxtaposition with the cold, dark, winter's night is:
The yellow rosebud on the table was just starting to bloom.
This detail contrasts the bleak, cold, and dark atmosphere of the winter night with the image of a blooming flower, which symbolizes warmth, growth, and the promise of spring. This sharp contrast highlights the tension between the harshness of the season and the delicate beauty of the rosebud, creating a more striking juxtaposition.