Hello,

Please add this code to the Theme Settings > Custom CSS > Global:

body .menu-simple-dropdown .sub-menu-dropdown, .menu-simple-dropdown .sub-sub-menu {
    background-color: transparent;
    border: 2px solid #866c40;
    border-radius: 5px;
}
body ul.sub-menu li a {
    color: white!important;
}
body ul.sub-menu li a:hover {
    color: #666666!important;
	background-color: transparent!important;
}

Best Regards