Need help with stretching the menu bar when scrolling back up

I need help with stretching the menu bar to full so that it goes over the picture in the video. I would appriciate if anyone could help

Problem: https://streamable.com/fmppqv https://ibb.co/fkVCnwX

I also have a custom CSS line going through under the bar so here are the settings for that in case you need it: https://streamable.com/p2ayv5

The page I need help with: [log in to see the link]