.nav5 ul > li:hover ul {
max-height: 1000px;
-webkit-transform: perspective(400) rotate3d(0, 0, 0, 0);
opacity: 1;
}
.nav5 li ul {
position: absolute;
left: 0;
z-index: 1;
max-height: 0;
overflow: hidden;
-webkit-transform: perspective(400) rotate3d(1, 0, 0, 90deg);
-webkit-transform-origin: 50% 100%;
-webkit-transition: 350ms;
-moz-transition: 350ms;
-o-transition: 350ms;
transition: 350ms;
margin-top: -100%;
top: -10px;
opacity: 0;
}