.parent {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    overflow: auto;
}
.txt {
    font-style: normal;
    font-size: 22px;
    font-family: Segoe, "Segoe UI", "DejaVu Sans", "Trebuchet MS", Verdana, sans-serif;
    width: 200px;
    text-align: center;
}
.butt {
    font-style: normal;
    font-size: 17px;
    font-family: Segoe, "Segoe UI", "DejaVu Sans", "Trebuchet MS", Verdana, sans-serif;
    width: 206px;
    text-align: center;
    background-color: #DDDDDD;
    border: thin solid #CBCBCB;
    height: 32px;
}

.block {
    width: 450px;
    height: 200px;
    position: absolute;
    top: 50%;
    left: 50%;
    margin: -200px 0 0 -225px;
    border: thin solid #E7E7E7;
    background-color: #F0F0F0;
    text-align: center;
    color: #151249;
    font-style: normal;
    font-size: 18px;
    font-family: Segoe, "Segoe UI", "DejaVu Sans", "Trebuchet MS", Verdana, sans-serif;
    padding-top: 20px;
}