How to change backgroundcolor of actionbar

Hi guys!

I can't get my head around the following issue after reading a lot about this. My app has got an hamburger-menu and two additional buttons in the actionbar. The problem is (as you can see in the screenshot below) that the actionbar isn't taking the same (green-ish) backgroundcolor as the rest of the app.

From what I learned after several attempts and spending several hours of investigating this issue, is that I need to use a navigationpage as a mainpage in my App.xaml.cs. So I've done that;

public App()
        {
            InitializeComponent();

            if (IsLoggedIn())
            {
                //MainPage = new MainPage();
                MainPage = new NavigationPage(new MainPage());
                //MainPage = new NavigationPage(new MainPage()) { BarBackgroundColor = Color.FromHex("#55BBAB"), BarTextColor = Color.FromHex("#FFF") };                
            }
            else
            {
                //MainPage = new LoaderPage();
                MainPage = new SignIn();
            }
        }

After adding the line of code which instantiates the NavigationPage, I was suddenly stuck with two actionbars! I finally got this fixed by setting the option 'SetHasNavigationBar';

        public MainPage()
        {
            InitializeComponent();

            MasterBehavior = MasterBehavior.Popover;

            ////https://stackoverflow.com/questions/51824298/duplicate-xamarin-navbar-toolbar-items?rq=1           
            NavigationPage.SetHasNavigationBar(this, false);

            //MenuPages.Add((int)EMenuItemType.Browse, (NavigationPage)Detail);
        }

But whatever I try, I can't change the color of the actionbar / navigationbar. I tried suggestions similar to these;

• https://forums.xamarin.com/discussion/98711/change-background-color-of-toolbaritems
• https://stackoverflow.com/questions/32147926/setting-background-color-of-xamarin-toolbaritems
• https://stackoverflow.com/questions/25726604/change-actionbar-color-xamarin

But none of them seem to work. Is there anyone here who can help me out on this one? It's driving me nuts!