html,body {
    height: 100%;
}
.dialog {
    position: fixed;
    top: 50%;
    left: 50%;
    margin-left: 0px;
    margin-top: 0px;
    width: 0px;
    height: 0px;
    overflow: hidden;
    border: 1px solid #999;
    text-align: center;
    border-radius: 25px;
    box-shadow: 5px 5px 5px #999;
    background: #88f;
    transition: all 0.3s;
}
.dialog .close {
    position: absolute;
    bottom: 10px;
    left: 50%;
    margin-left: -25px;
    width: 50px;
    height: 20px;
    border: 1px solid #999;
    background: #339;
    color: #fff;
    text-align: center;
}
#dialogswitch {
    display: none;
}
#dialogswitch:checked+.dialog {
    margin-left: -150px;
    margin-top: -100px;
    width: 300px;
    height: 200px;
}