.table .thead-dark th {
    color: #fff;
    background-color: #929497;
    border-color: #818283;
}
div.alert{
    cursor: pointer;
}
div.alert:hover{
    opacity: 0.6;
}
.table td, .table th { 
    vertical-align:  middle; 
}
.qrcode img{
    margin: auto;
}