#nav_drawer {
  position: relative;
  text-align: center;
  padding: 0 0 0 12px;
}

.nav_unshown {
  display:none;
}

#nav_open {
    display: inline-block;
    vertical-align: middle;
}

#nav_open span, #nav_open span:before, #nav_open span:after {
    position: absolute;
    height: 4px;
    width: 30px;
    border-radius: 3px;
    background: #fff;
    display: block;
    content: '';
    cursor: pointer;
    margin: 0 auto;
}
#nav_open span:before {
    bottom: -12px;
}
#nav_open span:after {
    bottom: -24px;
}

#nav_close {
    display: none;
    position: fixed;
    z-index: 99;
    top: 0;
    right: 0;
    width: 100%;
    height: 100%;
    background: black;
    opacity: 0;
    transition: .3s ease-in-out;
}

#nav_content {
    overflow: auto;
    position: fixed;
    top: 0;
    right: 0;
    z-index: 9999;
    width: 80%;
    max-width: 330px;
    height: 100%;
    background: #fff;
    transition: .5s ease-in-out;
    -webkit-transform: translateX(-105%);
    transform: translateX(105%);
}

#nav_input:checked ~ #nav_close {
    display: block;
    opacity: .5;
}

#nav_input:checked ~ #nav_content {
    -webkit-transform: translateX(0%);
    transform: translateX(0%);
    box-shadow: 6px 0 25px rgba(0,0,0,.15);
}

#nav_content ul {
    margin: 10px auto;
    padding: 0;
    width: 90%;
}

#nav_content li {
    border-bottom: 1px dashed #ccc;
    font-size: 14px;
    margin: 10px auto;
    padding: 10px 0;
    text-align: left;
    width: 100%;
}

#nav_content li:before {
    content: "■";
    margin: 0 5px 0;
}

#nav_content li a {
    color: #666;
    text-decoration: none;
}