Hello, should be this one - for classic menu:

@media all and (min-width: 1025px) {

.flexnav li a {    
background: transparent none repeat scroll 0 0;
padding: 0 5px;
position:relative;
border-left: medium none;
font-weight: 600;
font-family: 'Poppins', sans-serif;
color:#000;
font-size:12px;
line-height:20px;
display:block;
overflow:hidden;
-webkit-transition: all 0.15s ease-in-out;
transition: all 0.15s ease-in-out;
}

}

you may not need all CSS attributes for font attributes