Please change previous code to:
@media only screen and (max-width: 1290px) and (min-width: 992px){
.item-design-mega-menu .nav-sublist-dropdown > .container > ul {
padding-top: 1em;
}
.item-design-mega-menu .nav-sublist-dropdown .item-level-1.menu-item-has-children {
margin-bottom: 1.8em;
}
.item-design-mega-menu .nav-sublist-dropdown .nav-sublist a {
font-size: 0.8rem;
padding: 0em 1.5em;
}
.item-design-mega-menu .nav-sublist-dropdown .item-level-1 > a {
font-size: 0.9rem;
padding: 0.5em 1.5em;
}
}
Regards