How can I add colors to areas outside rounded corners in my header?

[toncic007]

Hi,

I would like to add colors to the area outside of my rounded corners on my header. See attached picture. (This is from another theme)


Do anyone know how to do this?
I have added the corners with this code into my css:

.theme__header {
border-bottom-left-radius: 35px;
border-bottom-right-radius: 35px;
border-top-left-radius: 35px;
border-top-right-radius: 35px;
overflow: hidden;
}

Right now I have a announcement bar above of the header and I would like that the color of the bar "blend" into my header.

The theme I use is Pipeline.

Can anyone help me with this?
Would really appreciate it!

/Adam