I may be kind of like you, angell, in that I tend to scoff at the idea of real magic and the idea of Wiccans having actual power. However the Church does teach that magic does exist. (The Catechism wouldn’t devote a section prohibiting something that doesn’t exist. We don’t have a section of the Catechism telling us it’s a sin to ride a Stegosaurus while making out with a Vulcan for example because there’s no need to put that in. So logically there was reason magic had to be addressed.)
In case you’re in interested in what the Catechism says,
2115 God can reveal the future to his prophets or to other saints. Still, a sound Christian attitude consists in putting oneself confidently into the hands of Providence for whatever concerns the future, and giving up all unhealthy curiosity about it. Improvidence, however, can constitute a lack of responsibility.
2116 All forms of divination are to be rejected: recourse to Satan or demons, conjuring up the dead or other practices falsely supposed to “unveil” the future.48 Consulting horoscopes, astrology, palm reading, interpretation of omens and lots, the phenomena of clairvoyance, and recourse to mediums all conceal a desire for power over time, history, and, in the last analysis, other human beings, as well as a wish to conciliate hidden powers. They contradict the honor, respect, and loving fear that we owe to God alone.
2117 All practices of magic or sorcery, by which one attempts to tame occult powers, so as to place them at one’s service and have a supernatural power over others - even if this were for the sake of restoring their health - are gravely contrary to the virtue of religion. These practices are even more to be condemned when accompanied by the intention of harming someone, or when they have recourse to the intervention of demons. Wearing charms is also reprehensible. Spiritism often implies divination or magical practices; the Church for her part warns the faithful against it. Recourse to so-called traditional cures does not justify either the invocation of evil powers or the exploitation of another’s credulity.
How does this differ from fictional magic? Depends on the fiction story but here are two examples.
Harry Potter: Harry’s magic comes from an innate ability that he was born with and is acted upon with a Latinesque language.
Lord of the Rings: Gandalf has innate ability by virtue of being a demigod. The power he calls upon is himself. (And because he’s in Middle Earth, not Earth, the Church’s rules don’t really apply to him anyways.)
In neither of those examples do the characters call upon evil spirits to do their bidding.
So magic, as defined by the Church, always involves calling on occult powers, which are not Heavenly, to have personal control. Now if you’re like me and are very skeptical of actual magic, just accept the wisdom of the Church and stay away from it anyways.