How I can expand the Header?

I’m modifying the Header, and when I upload the image, I saw that the picture does not fill the entire header, only the center and limited dimensions…
My Site:

How I can extend the header so that the image fills the red part?

I mean, this way:

Hi, apply custom css below (you can use simple custom css plugin if you like):

.site-branding {
    padding: 0;

.site-header .container {
    width: 100%;
    padding: 0;
    border-bottom: 1px solid #e86f67;

Thank u so much!!! It worked!