Angular-Material tab focus visual style not showing?

Below is an example from Angular Material showing the grayed-out box overlay when the tab component is focused by tabbing into it. https://material.angular.io/components/tabs/overview

But in my app, when I use the keyboard to tab into the tab component, there is no visual indicator showing that the tab is focused. There's literally no difference between the code. I copied and pasted the example code from Angular Material into my app and rendered it. Does anyone know I need to configure something in order for the focus style to show or anything I'm missing?

Oh and I'm using v18.2.3 of Angular-Material if that matters.

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