@kurtvindu-dk: Go to => Appearance => Customize => Additional CSS and add the following CSS Code.
To change color of sub-menu
.menu.catchbase-nav-menu li a {
background:#49a32c;
}
To change color of the active page
.catchbase-nav-menu .current-menu-item > a, .catchbase-nav-menu .current-menu-ancestor > a, .catchbase-nav-menu .current_page_item > a, .catchbase-nav-menu .current_page_ancestor > a, .sidebar-header-right .widget_nav_menu .current-menu-item > a, .sidebar-header-right .widget_nav_menu .current-menu-ancestor > a {
color:#fff;
}
Let me know if this solves your issue.
Regards,
Skandha