The names of typography classes differ between material 2 and 3. Material 2 uses classes like mat-h1, material 3 classes like mat-title-medium. I want my components to run with both and thought to use my own class name, e.g. my-headline and map that to either mat-h1 or mat-title-medium.

I thought, I could define something like the following:

.my-headline {
    @extend .mat-h1;
}

However, the compiler complains about not knowing .mat-h1.