Change color of one item in main menu to red (Impulse Theme)

Store Design
16 
li.site-nav__item.site-nav__expanded-item.site-nav--has-dropdown:last-child a {
    color: red;
}
.site-nav--has-dropdown:last-child a:hover {
    color: red !important;
}
a.site-nav__dropdown-link.site-nav__dropdown-link--second-level {
    color: #000 !important;
}

Add this css at the bottom of
Online Store->Theme->Edit code->Assets->theme.scss.liquid