Do you have a photo of that part of the bathroom?
Yellow and blue is nice together.
Think of the iris flower, and the cornflower.
I would get a white cabinet.
A wood cabinet would be introducing yet another color.
You can paint the mirror frame over the sink white.
You can add color accents in accessories in shades of yellow and blue.
On the wall perpendicular to the sink over where you have the single towel bar, I would mount a hotel towel rack and you could put your blue towels on it and they would look just smashing against the yellow walls.
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One curb less shower room
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