i created my own custom theme with a custom font:

```
@import '~@angular/material/theming';
@include mat-core();
$custom-typography: mat-typography-config($font-family: '"work sans",    sans-serif;');
@include mat-core($custom-typography);

```

Now i want to use the font "Oswald" for every header(h1-h6). How can i do this?