Hi rborst
You can use this custom CSS:
.t4-palette-section_copy .nav>li a,
.t4-palette-section_copy .nav>li .nav-link,
.t4-palette-section_copy .t4-megamenu .navbar-nav>li.active>a,
.t4-palette-section_copy .t4-megamenu .navbar-nav>li.active>.nav-link {
color: #fff !important;
}
.t4-palette-section_copy .t4-megamenu .nav>li a .item-caret,
.t4-palette-section_copy .t4-megamenu .nav>li .nav-link .item-caret {
border-top-color: #fff;
}