better to show your codebase

I guess it's just a normal hydration error

I created new project and in page tsx added this and i have error
this is my page.tsx 'use client'
import { FC } from "react";

const App: FC = () => {
return (
<h1>Hello World!</h1>
)
}
export default App;

why do you need "use client" there?

because i want to make full screen app and when i add only use client was error

well, don't you get hydration error without "use client"?

I don't see anything wrong in your code

remove "use client" and see if you still get an error in the console

when i add useRef for full screen i have error that i must used in client this

well @BigJHN show me your full code

unless I can't help you properly

it can't happen

@BigJHN also us js semantic tics to make the code look better