If you want hardwood see link for reference.
But I recommend particle board or plywood. Or if you can find Ikea type of cardboard core board it is even better. Hardwood or MDF is very heavy. You can't even move it easily afterwards without scratching your floor.
Or you can just make a thick edge only so only the edge is say 2 inch think but the rest of the board is 3/4 or 1 inch thick (still very heavy if use hardwood or MDF). So you might still want to use plywood.
But I recommend particle board or plywood. Or if you can find Ikea type of cardboard core board it is even better. Hardwood or MDF is very heavy. You can't even move it easily afterwards without scratching your floor.
Or you can just make a thick edge only so only the edge is say 2 inch think but the rest of the board is 3/4 or 1 inch thick (still very heavy if use hardwood or MDF). So you might still want to use plywood.