This shows a darker vanity, with the wainscot "look" using trim and paint - I know you would like a darker floor, but his has a nice feel.
Q
This is a classic variation - black and white basket weave on the floor - white fixtures and dark vanity continue the black/ white theme.
This pic and next are the same room - I found it soothing - soft green in the accent tile, picked up by the paint - still using a dark vanity.
Similar
A different feel -
a more modern light wood - with the mosaic backsplash accent - with dark floor.
cherry cabinet - using black and white primarily - with a special border -
A bit more playful with the tile -
a bit more modern - but, not harsh -
(Master) Various large sized slate, or slate toned tile on floor and walls - unified look with gray counter and gray painted wall.
This shows a darker vanity, with the wainscot "look" using trim and paint - I know you would like a darker floor, but his has a nice feel.
Q