<summary> semantic HTML element is used as a summary, label, or caption, for the
<details> element is in an “open” or “closed” state, the
<summary> text is always visible.
<summary> element can only be used as a first child element of the
<details><summary>Summary goes here</summary><!-- Additional content goes here which will be toggled --></details>
<!DOCTYPE html><html><head> </head><body><details><summary>Course Prerequisites</summary><p>To enroll in ECON 102, you must've passed ECON 101 in a previoussemester.</p><!-- This can also include any other content e.g., images and GIFs --></details></body></html>