The browser approach is best effort at rendering, rather than enforcing conventions. And I doubt that tooling can help with all the complicated ways in which H

The browser approach is best effort at rendering, rather than enforcing conventions. And I doubt that tooling can help with all the complicated ways in which HTML is generated (React, SSR etc). I was actually surprised at how underbaked editor support for CSS is in VSCode (the most widely used frontend editor). If the most modern tooling can't understand that a CSS variable is declared in a different file and autocomplete it for me in a .vue file, I get the impression that tooling is severely lagging behind the frameworks.