Materialize CSS Collapsible Popout

HTML5

HTML5 (No space between "HTML" and "5")is a markup language.
CSS3

The first working draft of CSS3 came in 19-01-2001.
Material Design

Materialize is a User Interface (UI) component library. Introduced by Google (2014 – Present).
Bootstrap 4

Bootstrap is the most popular HTML, CSS and JavaScript framework for developing responsive, mobile-first web sites.