rabbit safe waterproof/resistent paints/stains?

my daughter got a rabbit and is slowly working on a large enclosure for him. she has ramps and levels made of wood and I would like to make the wood at least slightly water resistant so the bunny pee ( until she gets it litter box trained which she is working on) doesn't completely soak into the wood. are there any shellacs or something of the sort that are safe in case the bunny decides to nibble on the wood? any advice would be greatly appreciated

I think shellacs and lacquer aren't bunny-safe, but paints might be if they're unleaded? Not 100% sure though. Personally I wouldn't risk it, as you can bet your bunny will be gnawing on the wood quite a lot.

Bunnies don't generally pee on ramps unless they're incontinent. Even unfixed, hormonal, territory-marking rabbits tend to be picky about toilet spots and pee on nice, flat surfaces. A spraying bunny might fling some pee on the wood, but not much. If you're planning on fixing the bunny as soon as he/she reaches puberty you'll likely have nothing to worry about.

Have you thought about horizontal panels/boxes to function as steps instead of ramps? Ramps are slippery on furry feet, steps tend to work much better. And if your bunny does turn out to be an indiscriminate pee-er, you can wrap puppy pee pads or old blanket strips around them to catch stray pee for easy washing.

For indoors? I guess a natural wax could work - you might need to then add something non slip over. You can also use lino/safety flooring cut to size and glued on or attached with trim. Again watch the slipperiness.

They now make some very gritty, textured linoleum that could be used on wood surfaces that would be wipeable. If bunny chew the edges, though, then a corner bead or something might need to be used to prevent bunny from getting the edge.