i would like to make my secoundry menu mobile responsive when the browser gets

i would like to make my secoundry menu mobile responsive when the browser gets smaller i want it to hide
symoninc.com

/* SECONDARY MENU */

@media (max-width: 979px) { 

#secondary-menu ul { text-align: center; list-style-type: none;}

#secondary-menu ul li {display: inline-block; padding: 0 5px;
position: relative;
    top: -77px;
  }
}
/* Target the  secoundry menu item LI */
.menu li.terms1234{
font-size: 1em;
}