On the page mentioned below where I'm testing the implementation of a video background, I'm able to achieve to embed a YouTube video with full background and overwrite the size and overflow visibility to achieve what I'm hopefully we can see on a desktop.

However, I'm not having the same success when displaying it on a mobile. The video always appears resized, no matter what I do in custom css. I have created a duplicated section only visible to mobiles. The section for desktop and laptop is hidden when mobile sections are triggered. Can you give a look and some help on this? Thanks