CSS-Only Widgets Are Inaccessible

I wrote a short post last week on burger menus using the <summary> tag. It should be accessible, being more or less the intended use for the element, but curious to see HN rip it apart :)

https://lucas-levin.com/code/blog/burger-navigation-menu-wit...

I quite like theme toggles in the vain of the only featured, and notably that they work without javasvript enabled. Is there a simple fix to make them accessible without relying on JavaScript buttons or server side query processing?