<details> and <summary> elements. I wanted to share my findings and see if anyone else has encountered similar behaviour.<details> elements work:<details> element can now accept display:flex and display:grid properties.::details-content. No more wrapper divs needed.<details> element display property to contents so that I can lay out a group of details elements into a sort of responsive tabbable UI. display:contents property entirely. As far as the dev tools are concerned, it's applied correctly, but just ignores it and resolves to the browser's display:block behaviour; and reports it as such too.&::details-content {... fix: https://codepen.io/marknotton/pen/RwXXodo?editors=1100