.LockOff { 
    display: none; 
    visibility: hidden; 
}

.LockOn {
    /*display: block;*/
    visibility: visible;
    position: fixed;
    z-index: 999;   
    top: 0px;
    left: 0px;
    width: 100%;
    height: 100vh;
    background-color: #252525;
    text-align: center;
    color: white;
    font-size: 27px;
    padding-top: 20%;
    filter: alpha(opacity=95);
    opacity: 0.95;
}