I do see that the image is not 100% the width of the page.
Is it possible to login and see what i can do to help with that?
Custom CSS is possible but shouldnt be needed. If the fullscreen slider is defined correctly it should be "Fullscreen". I see you issue and am sorry that my replies have not been prompt ⭐️
You are welcome to contact me via 'Chats' or email: licensekeys@laytheme.com I am happy to login and sort this issue out properly rather than adding custom code. It should be true "Fullscreen" 🌝
Talk soon and thanks for your patience Tim Richard