This is a implementation of tab panels that uses amp-selector. Tabs and tab panels are positioned via flexbox and amp-selector uses the selected attribute to show/hide the correct tab panel and style the selected tab.
Each of the amp-accordion component’s immediate children is considered a section in the accordion. Each of these nodes must be a section tag. Each section must contain only two direct children. The first child (of the section) will be considered as the heading of the section. Clicking/tapping on this section will trigger the expand/collapse behaviour. Use the disable-session-states attribute to disable preserving the accordion state across a session.
amp-accordion adds the expanded attribute to any expanded element. You can use CSS attribute selectors to style an accordion section based on whether it's expanded or collapsed. Use section[expanded] to style the expanded state and section:not([expanded]) to style the collapsed state.