I have a fullscreen youtube video embedded on my website.

It looks goo
I spent a lot of time trying to figure this out but here's a simple CSS solution that works for me using Flexbox. Basically, put the video in a container with position absolute and width and height 100% and the make it display:flex and center the content!
https://medium.com/@rishabhaggarwal2/tutorial-how-to-do-full-screen-youtube-video-embeds-without-any-black-bars-faa778db499c