#nav-icon {
width: 55px;
height: 45px;
position: relative;
margin: 50px auto;
transform: rotate(0deg);
transition: .5s ease-in-out;
cursor: pointer;
}
#nav-icon span {
display: block;
position: absolute;
height: 5px;
width: 100%;
background: #000;
border-radius: 40px;
opacity: 1;
left: 0;
transform: rotate(0deg);
transition: .25s ease-in-out;
}
#nav-icon span:nth-child(1) {
top: 0px;
}
#nav-icon span:nth-child(2) {
top: 15px;
}
#nav-icon span:nth-child(3) {
top: 30px;
}
#nav-icon.open span:nth-child(1) {
top: 18px;