The initial and unset CSS wide values are already in development in Microsoft Edge. The all shorthand property is now on the backlog with a priority of medium. You can track status updates at https://dev.modern.ie/platform/status/cssallshorthand/Marco Colli commented
Any updates? All browsers including Safari now support this feature. It is very useful for widgets and components.
We’re pleased to announce that the details and summary elements are now under development :)