body {
background-image: url("img/01.jpg");
background-repeat: no-repeat;
background-attachment: fixed;
background-position: right bottom
}
label {
    background: green;
    color: #fff;
    padding: 10px;
    display: block;
    margin: 0;
    border: 1px solid #fff;
}

input[type="checkbox"].on-off{
    display: none;
}

.menu ul {
    -webkit-transition: all 0.5s;
    -moz-transition: all 0.5s;
    -ms-transition: all 0.5s;
    -o-transition: all 0.5s;
    transition: all 0.5s;
    margin: 0;
    padding: 0;
    list-style: none;
}

.menu li {
    padding: 5px;
}

input[type="checkbox"].on-off + ul{
    height: 0;
    overflow: hidden;
}

input[type="checkbox"].on-off:checked + ul{
    height: 200px;
}