Is there a bug or something is not right

Can someone help me with this as I’m not sure what to do I’ve noticed that when I preview my story in the app, some overlay animations don’t act out as they do in the Portal, and also that some of the directing is off. I write my story on a computer. Using google Chrome. And yet when I look at the app the characters are different sizes

When you are on mobile, the size of the screen changes.

should i go by the coding on the phone to make sure it looks right?