Why is the header image multiplying when scrolling?

Hi. I created a custom header for the theme and when you use Ctrl+MouseScrollDown, you can see the header multiplying. It shouldn’t behave like this, the header should stretch to the both edges of the page at maximum scrolling.

And one more thing, I couldn’t find the padding or margin or whatever the white space above and under the navigation is. I want to make it smaller. Thanks in advance.

http://www.cncoutlet.ro