[auxiliarymoose]

Accordion behavior is discussed in the article in the "Accordions / Expanding Content Panels" section:

> Use the same name attribute on all related details (like radio buttons) to restrict only one open panel at a time

And tabs can be a <details>-based accordion with some creative CSS to adjust the layout (left as an exercise for the reader, but I could write up an example if that would be helpful!)

[iammrpayments]

It won’t have the necessary keyboard shortcuts.

[extra88]

Yes, the tabs in a tabs pattern should be keyboard navigated using arrow keys (ironically not the Tab key).

Also, the summary for the currently open details element will have the wrong state, 'expanded' instead of 'selected'. And while a set of details can now have a maximum of one open at a time, you can't ensure exactly one is always open (without JavaScript) as the tabs pattern requires.