.glass-preview{
    display:none;
}

@media (min-width: 768px){
    .glass-preview {
        width: 400px;
        height: 400px;
        position: absolute;
        /*border-radius: 50%;*/
        cursor: none;

        /* Multiple box shadows to achieve the glass effect */
        box-shadow:
              0 0 0 7px rgba(255, 255, 255, 0.85),
              0 0 7px 7px rgba(0, 0, 0, 0.25),
              inset 0 0 40px 2px rgba(0, 0, 0, 0.25);

        /* hide the glass by default */
        display: none;
        z-index: 1000;
    }

    .glass-preview.glass-on{
        display: block;
    }
}