Scope CSS side effect to route?

[aaronadamsCA]

With Vite, I was hoping I could create a route.css file for one route:

:root {
  background-color: black;
}

Import it as a side effect in that route:

import "./route.css";

...

And have it only affect that route.

In reality, the Vite dev server leaves these styles in place after navigating away from the route.

Is this a bug, or just a limitation of the dev server and/or side-effect imports? Because I would love to be able to scope CSS like this, I'm just not sure if this is meant to work or not.