.navigation-menu {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient:vertical;
    -webkit-box-direction:normal;
    -ms-flex-direction:column nowrap;
    flex-direction:column nowrap;
    justify-content: space-between;
    flex-wrap: nowrap;
}

.navigation-menu__link:not(:last-child) {
    margin-right: 8px;
}

@media (min-width:768px) {
    .navigation-menu__link:not(:last-child) {
        margin-right: 15px;
    }
}