mask.css

html,body{
    margin:0;
    height:100%;
    cursor: crosshair;
}

#target{
    width: 100%;
    opacity: 0.9;
}

#snackbarLoad {
    visibility: hidden;
    min-width: 250px;
    margin-left: -125px;
    background-color: #333;
    color: #fff;
    text-align: center;
    border-radius: 2px;
    padding: 16px;
    position: fixed;
    z-index: 1;
    left: 50%;
    bottom: 30px;
    font-size: 17px;
}
  
#snackbarLoad.show {
    visibility: visible;
    -webkit-animation: fadein 0.5s, fadeout 0.5s 2.5s;
    animation: fadein 0.5s, fadeout 0.5s 2.5s;
}
 
#snackbarText {
    visibility: hidden;
    min-width: 250px;
    margin-left: -125px;
    background-color: #333;
    color: #fff;
    text-align: center;
    border-radius: 2px;
    padding: 16px;
    position: fixed;
    z-index: 1;
    left: 50%;
    bottom: 30px;
    font-size: 17px;
}
  
#snackbarText.show {
    visibility: visible;
    -webkit-animation: fadein 0.5s, fadeout 0.5s 2.5s;
    animation: fadein 0.5s, fadeout 0.5s 2.5s;
}

@-webkit-keyframes fadein {
    from {bottom: 0; opacity: 0;} 
    to {bottom: 30px; opacity: 1;}
}
  
@keyframes fadein {
    from {bottom: 0; opacity: 0;}
    to {bottom: 30px; opacity: 1;}
}
  
@-webkit-keyframes fadeout {
    from {bottom: 30px; opacity: 1;} 
    to {bottom: 0; opacity: 0;}
}
  
@keyframes fadeout {
    from {bottom: 30px; opacity: 1;}
    to {bottom: 0; opacity: 0;}
}