How to change the size of the website customer service chat window

I use Tidio’s customer service plug-in. But there is a problem, it is fixed and cannot be moved. When I set the return to top button, it will sometimes be blocked, so I moved the button of the chat window up, but after moving it, I found that the expanded chat window was too large. , how can I change the size of this window?

My site url is https://popgoo.com/

@WinnieLin That can be fixed inside the app. Please ask app developer or check settings inside the app.