.hamburger {
    width: 20px;
    height: 16px;
    position: relative;
    -webkit-transform: rotate(0deg);
    -moz-transform: rotate(0deg);
    -o-transform: rotate(0deg);
    transform: rotate(0deg);
    -webkit-transition: 0.5s ease-in-out;
    -moz-transition: 0.5s ease-in-out;
    -o-transition: 0.5s ease-in-out;
    transition: 0.5s ease-in-out;
    cursor: pointer;
}
.hamburger-toggle {
    cursor: pointer;
}
.hamburger_open {
    z-index: 9;
}
.hamburger_open span:nth-child(1) {
    top: 18px;
    width: 0;
    left: 50%;
}
.hamburger_open span:nth-child(2) {
    -webkit-transform: rotate(45deg);
    -moz-transform: rotate(45deg);
    -o-transform: rotate(45deg);
    transform: rotate(45deg);
}
.hamburger_open span:nth-child(3) {
    -webkit-transform: rotate(-45deg);
    -moz-transform: rotate(-45deg);
    -o-transform: rotate(-45deg);
    transform: rotate(-45deg);
}
.hamburger_open span:nth-child(4) {
    top: 18px;
    width: 0;
    left: 50%;
}
.hamburger span {
    display: block;
    position: absolute;
    height: 1px;
    width: 100%;
    border-bottom: 1px solid #2d2b2c;
    opacity: 1;
    left: 0;
    -webkit-transform: rotate(0deg);
    -moz-transform: rotate(0deg);
    -o-transform: rotate(0deg);
    transform: rotate(0deg);
    -webkit-transition: 0.25s ease-in-out;
    -moz-transition: 0.25s ease-in-out;
    -o-transition: 0.25s ease-in-out;
    transition: 0.25s ease-in-out;
}
.hamburger_open span {
    background: #000;
}
.hamburger span:nth-child(1) {
    top: 0;
}
.hamburger span:nth-child(2) {
    top: 8px;
}
.hamburger span:nth-child(3) {
    top: 8px;
}
.hamburger span:nth-child(4) {
    top: 16px;
}