[Feature request] Allow to set custom z-index

[HanggiAnggono]

Hi, first of all i want to say thank you for making this extension, helped me to avoid going total fullscreen on mac and switching desktop. But is there a way to add options for custom z-index or even custom css ? because i'm using speed controller plugin, and i can't see the controller when video is expanded.

example, i need to see the controller on the top left