.block {
    text-align: center;
    background: rgba(20,20,20,0.5);
    margin: 0;
    position:fixed;
    top:0;
    left:0;
    width:100%;
    height:100%;
    z-index:20000;
}

.block:before {
    content: '';
    margin-left: -0.25em;
    display: inline-block;
    height: 100%;
    vertical-align: middle;
}

.centered {
    display: inline-block;
    vertical-align: middle;
    width: 300px;
    max-height:97vh;
    /*overflow:auto; because of f%/&%/%ing stupid ie / edge can't use auto here as it has rounding issues (sometimes white line on the right title bar)*/
    padding: 10px 10px;
    border: #63b32e solid 3px;
    background: #ffffff;
    margin:0 15px;
}