Native Web Components

My first attempt to create a single page app with only js native web components. For learning purposes there's a lot of "wheel-reinventing". The app has:

• a router working on top of window.history
• theme context attached to body to coordinate the whole theme app. (since web components are css isolated, this "injects" theme css variables in each web component)
• centralized state on home page (similar with redux)
• custom events for communication between components

I'm sure there are a lot mistakes using this aproach, so any feedback is more than welcome :).