Pixel art changing once importing into unity

So I made a conveyor belt in photoshop, imported it into unity, but for some reason it distorts the grey lines and just looks bad overall. I tried messing with all of the unity import settings, but nothing seemed to fix it. In the original image (sorry I don't want to share it) the lines go light gray - dark gray - light gray etc. , but in unity it bunches like 2-3 lines and removes some of them.