Magic is not something necessarily to do with the supernatural; that is a matter of belief, not fact.
Magic is defined by some as change in compliance with will.
A lot of atheistic practices treat entities as tropes, or archetypes, or aspects of the human psyche.
Many spiritual practices rely on phenomena known to exist solely in the brain, but are interpreted as something more.
Magic is not spiritual belief. A lot of people tie their magic practice together with religious practice and spiritual belief, but largely this comes from the tendency to do the same with just about everything before people learned as much about the world and the way it works as we now know and continue to learn.
People still may believe many things are influenced by the supernatural, but again this is more a decision to believe than an actual fact.