Platform Specific Styles rc0

In beta 11, I was doing this to do platform specific styling:

.md {
       background-color: white;

With rc0, I have the following lines in different files:
in html, i have this: <ion-content class="home-page">,
in ts:

    selector: 'home-page',
    templateUrl: 'home-page.html'

And in scss:

home-page {
    .md .home-page {
        background-color: white;

I can read this in the docs: <ion-app class="md">

Each platform has a default mode, but this can be overridden. For example, an app being viewed on an Android platform will use the md (Material Design) mode. The will have class=“md” added to it by default and all of the components will use Material Design styles.

But I’m not able to apply different stylings to different platform yet. What am I missing?