Changing the background colour on the nav.header.list

Is it possible to make the background behind the navigation text ONLY go all the way to the edge like this screenshot attached? I can get the grey colour behind the text using some code but it doesn't go all the way to the edge:

nav.header-nav-list { 
    -ms-flex-wrap: nowrap !important;
        flex-wrap: nowrap !important;
background:#566175!important; 
}
div.header-nav-item--active>a {
    color: #e95d43 !important;
}
.header-nav-item a:hover {
    color: #e95d43 !important;
}
.header-menu-nav-item a {
    font-size: 14px;
}
/* Nav black */
nav.header-nav-list>div {
    background-color: #566175;
    padding-right: 4%;
    padding-left: 4%;
}

What is site url?