.overlay
{
    opacity: 0.8; background-color: rgba(0, 0, 0, 0.7);
    position: fixed; width: 100%; height: 100%;
    top: 0; left: 0; z-index: 1000;
}

.overlay:target
{
    visibility: hidden; opacity: 0; display: none;
}

.progress
{
    color: #FFFFFF; font-size: 30px; margin: 0 auto; 
    width: 1em; height: 1em; border-radius: 50%; 
    position: absolute; top: 50%; left: 50%; 
    animation: CircularProgress 1.3s infinite linear;
}

@keyframes CircularProgress
{
    0%, 100% { box-shadow: 0 -3em 0 0.2em, 2em -2em 0 0em, 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, -2em 2em 0 -1em, -3em 0 0 -1em, -2em -2em 0 0; }
    12.5%    { box-shadow: 0 -3em 0 0, 2em -2em 0 0.2em, 3em 0 0 0, 2em 2em 0 -1em, 0 3em 0 -1em, -2em 2em 0 -1em, -3em 0 0 -1em, -2em -2em 0 -1em; }
    25%      { box-shadow: 0 -3em 0 -0.5em, 2em -2em 0 0, 3em 0 0 0.2em, 2em 2em 0 0, 0 3em 0 -1em, -2em 2em 0 -1em, -3em 0 0 -1em, -2em -2em 0 -1em; }
    37.5%    { box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, 3em 0em 0 0, 2em 2em 0 0.2em, 0 3em 0 0em, -2em 2em 0 -1em, -3em 0em 0 -1em, -2em -2em 0 -1em; }
    50%      { box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, 3em 0 0 -1em, 2em 2em 0 0em, 0 3em 0 0.2em, -2em 2em 0 0, -3em 0em 0 -1em, -2em -2em 0 -1em; }
    62.5%    { box-shadow: 0 -3em 0 -1em, 2em -2em 0 -1em, 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 0, -2em 2em 0 0.2em, -3em 0 0 0, -2em -2em 0 -1em; }
    75%      { box-shadow: 0em -3em 0 -1em, 2em -2em 0 -1em, 3em 0em 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, -2em 2em 0 0, -3em 0em 0 0.2em, -2em -2em 0 0; }
    87.5%    { box-shadow: 0em -3em 0 0, 2em -2em 0 -1em, 3em 0 0 -1em, 2em 2em 0 -1em, 0 3em 0 -1em, -2em 2em 0 0, -3em 0em 0 0, -2em -2em 0 0.2em; }
}