.popup {
    text-align:center;
    margin-left: -50px;
    margin-top: 50px;
    width: 750px;
    height: auto;
    position: fixed;
    background: #fff;
    padding: 30px;
}


.b-close {
    position: absolute;
    right: 0;
    top: 0;
    cursor: pointer;
    color: #fff;
    background: dodgerblue;
    border: none;
    padding: 5px 10px;
}

.b-close:hover{
    background: red;
}