Using Document Level Styles
Document level styles are set into the head of a document. They can be applied throughout the body of a document.
(In contrast, the inline styles are set into a tag and can never be applied to any more than a single element in the body.)
Document level styles are sometimes known as global styles. (Why? ~ I don't know why. I suppose someone might imagine one's own document to be a world of its own, hence global.)
You may choose whichever term appeals to you, whether document level styles or global styles.