details element The HTML details element (<details>) is used as a disclosure widget from which the user the retrieve additional information, nav element The HTML Navigation Element (<nav>) represents a section of a page that links to other pages or to parts within the page: a section with navigation links, em element Specifies that the enclosed text should be emphasized. These elements allows child elements from interactive, embedded, heading, sectioning, phrasing, and metadata content categories.
Click the html element name in the punctuation list to advance the example in 'Tryit-Editor':