Contemporary classical music is music that is modern and new, but still falls under the category of classical music. Classical music is a type of music that is usually played by an orchestra or some other big group of musicians.
Think of it like building a house. Classical music is like building a big, beautiful mansion with fine materials and perfect symmetrical designs. Contemporary classical music is like building a modern, glass skyscraper with unusual shapes and different materials. Both are different, but still buildings.
Contemporary classical music often uses new and different sounds and instruments that are not usually used in traditional classical music, such as electronic components or metal objects. This also means that the melodies, rhythms, and harmonies in contemporary classical music might sound strange, unexpected, or complicated to some listeners.
But just because it's different doesn't mean it's bad. Some people really enjoy listening to contemporary classical music because of its uniqueness and creativity. And, like any type of music, it's all a matter of personal taste.