Nothing happens if i uses a class, but as soon as i change it to and id -> the background-color for the whole page changes, and still not the navigation-bar.
I might have some problems in my index.html that overwrite the class.
Are you using the browser to test? You should be able to inspect the element in the browser and see which class is overriding yours. Also, I’m not sure where your navigation-bar is defined, but mine is an ion-nav-bar above the ion-nav-view, so changing the background-color on the ion-view will not affect the background color of the navigation bar. Here’s a snippet from my index.html: