Theme & Search Help…Thanks

First Happy New Years to everyone. I’m having two problems and not really sure how to fix them.

1. As you can see the body and header are not link together, their is a space. I know what code is messing it up but I’m not sure how to fix it. I want the blue/light gray body to touch the dark gray bar?

2. The “search” field is centered but not in the middle of the dark gray bar and looks completely wrong in Firefox?

The test site is https://animegamingnetwork.com/testnr/ and thanks for any help.