Fullscreen slider

Hi,
I know your plugin usually does not have a fullwidth and fullheight option for the slider, but I was wondering if you could help me with some css in order to make a full screen slider that goes beneath my header/main navigation(like a hero image slider).

I know with a neagtive margin I can make the slider move up to the top, but how can I make it fullwidth and fullheight? Using 100vh and 100vw does not work.

I really like your plugin due to its simplicity and have not found any other slider plugin this lightweight and simple.

Thanks!