If gravity pulls things inwards how come if you let a balloon into the sky it goes up?

We forget that gravity is also pulling the air inwards and if the balloon is lighter than the same volume of surrounding air then the air “wins” and the balloon is left to float away until the surrounding air is thinner and has an equal pull then it floats at that constant height, provided, of course, it doesn’t burst with the reduced air pressure allowing the internal gas to expand beyond the balloon’s capability to contain it.