> Edge is breaking this cardinal rule: Browser chrome belongs to the browser, but the content area belongs to the application alone.
It's funny, for me this is not at all what the web is about. I see CSS styles as at best a suggestion for how the website would like to be rendered, but the browser is fundamentally a user agent that can render stuff however the user likes. If you don't like how Edge renders things, you can always switch to a different browser or change the settings.
Web applications should be designed with this in mind: control of the client experience is in the hands of the user or the user's agent. When a web application is designed this way, it is natively the most accessible kind of app that can exist, usable with a screen reader, terminal GUI, mobile, desktop, or even a scriptable web driver. In contrast, web apps that obsess over having minute control over every detail of the presentation tend to be clunky, nonresponsive and inaccessible.
In my mind, the more heterogeneous web browsers are, the more web applications are forced to handle for different configurations, and the better the ecosystem will be overall. For once I think Microsoft is doing something web-related that I actually approve of.
[0] https://www.neowin.net/news/microsoft-edge-will-let-you-disa...