body {
    height: 100%;
    background-color: #556
}

.screen_data {
    max-width: 600px;
    margin: 0 auto;
    border: 1px dotted #CCC;
    padding: 50px;
    background: #FFF;
    border-radius: 50px;
}

@media (min-width:768px) {
    .main-container {
        width: 100%
    }
}

@media (min-width:992px) {
    .container {
        width: 600px
    }
}