Site para escolher a cor: https://htmlcolorcodes.com/
Script
.header-wrapper {
background-color: #0E1B4D!important;
}
.header__icon:not(.header__icon--summary), .header__icon span, .header-wrapper span, .header__menu-item, .icon-caret {
color: white!important;
}
.header__submenu .header__menu-item {
color: black!important;
}
Esse tutorial foi util?