add wood wallpaper to the kick plates of the stairs. Those rolls are expensive but you would only need one. Not practical with white treads though, it will be stuffed up from black shoe soles in no time.
Kitchen or anywhere DIY. Seems simple enough, depending on your gap between shelves, anywhere from ropes to ropes for your spacing. You could even use wider wood, just adjust your rope length to accommodate your width and height of your shelves.