If something is termed "legal", it is approved by the law. If it has not been addressed by the law yet, it means that it is not totally legal, just as it is not yet totally illegal. Just so you know, you still have to be very secretive with your gambling because if there is a situation where you get arrested by the government, they know the law better than you may do, and there may be a related law that you may be judged with just so you will be found guilty.

Keep your gambling activity private if you are in a country where there are no clear rules regarding gambling.