Aside is reserved for sidebar content that is dependent on the content present in an article or section of an article. The <aside> element is not intended, for example, to serve as a container for navigation content (navigation content is supposed to be identified by and wrapped in the <nav> element discussed earlier).
Given that aside content is generally formatted as a sidebar, there is a particular style generally associated with the use of <aside> elements: Float. The CSS Float attribute moves a container to the left-hand side (float:left) or to the right-hand side (float:right) of other content, and flows other content around the container. When we'll define CSS styles for our HTML5 semantic layout elements at the end of this chapter, we'll be sure to float our <aside> element style.