To make your small bathroom with low ceilings feel more spacious, opt for light, airy colors. Painting the walls and ceiling the same light color can create the illusion of height and openness. Consider soft colors like light blues, pale greens, or subtle grays to enhance the sense of space. Keeping the ceiling the same color as the walls will help avoid visual interruptions that can make the ceiling appear lower.

For the trim, painting it the same color as the walls can create a seamless look that promotes continuity and visual flow. This approach can help avoid drawing attention to the trim and instead make the walls appear elongated.

However, if you prefer a classic look, painting the trim white can provide a crisp contrast against the light-colored walls and ceiling, adding a touch of brightness and definition to the space. White trim can also help to frame the elements in the room, such as the window and vanity, making them stand out.

Ultimately, the choice between painting the trim white or the same color as the walls/ceiling will depend on your personal preference and the overall aesthetic you want to achieve. Just ensure that whatever color scheme you choose, it complements the existing features in your bathroom and enhances the sense of openness and height you are aiming for.