Hello! 

You need to add CSS rules to the Studio->Lucid->Styles->Custom Styles area:

/* Mobile menu text, border - color, size  */
.cd-dropdown .cd-dropdown-content a, .cd-dropdown .cd-dropdown-content ul a {
    border-top-width: 1px;
    border-color: rgba(255,255,255,.1);
    border-style: solid;
    font-size: 1rem;
    font-weight: 600;
    color: rgb(255, 0, 0);
}
/* END Mobile menu text, border - color, size  */

! Delete unused code !