.header {
    background-image: url('20210131_131641.jpg');
    height: 33vh;
}
@media only screen and (min-width: 1024px) {
    .header {
        height: 50vh;
    }
}
.viewer {
    width: 340px;
}
@media only screen and (min-width: 640px) {
    .viewer {
        width: 600px;
    }
}
@media only screen and (min-width: 1024px) {
    .viewer {
        width: 800px;
    }
}