Obsidian 1.1.9 is using Electron v21 and Chrome 106 so the :has() selector is now available! 
Make sure to reinstall using the latest installer if you previously had an older version and only updated within the app. This is necessary to get the latest Electron / Chrome version.
The :has() selector opens a lot of possibilities! I’m currently experimenting with it to achieve the same result as the contextual-typography plugin with pure CSS alone (no plugin required).