Why do we need to use element when we have already stated class?

Question

In css, if a person has already stated a class then why does he need to use element after that like what will be the benefits of doing that. For example: There is a class of "content" in element So what will be the difference in css between: .content h1 {...} And .content {....}

Answer 1

.content h1代表任何h1标签到所有具有 class 作为content的元素内的任何级别的子组件，而.content指的是具有 class 作为content的元素。