Reliably apply custom css to navbar

I’m currently trying to apply some custom css to the lovelace navbar. To do this I created a js file and added it as a lovelace ressource.
The problem is that when one changes the current dashboard, the navbar (more specificly ha-panel-lovelace) gets recreated but my js ressource does not get reloaded.

I could of course use a mutationObserver but it feels kinda hacky.

Are there some events I could listen to or other intended ways?

Happy to hear your ideas!

Many thanks!