/* unvisited link */
a:link { color: black; text-decoration: none; }
a:visited { color: black; text-decoration: none; }
a:hover { color: black; text-decoration: none; }
a:active { color: black; text-decoration: none; }

.column {
    float: left;
    width: 25%;
}

/* Clear floats after the columns */
.row:after {
    content: "";
    display: table;
    clear: both;
}

.center {
    margin: auto;
    width: 50%;
    /*border: 3px solid green;*/
    padding: 10px;
}

@media all and (max-width: 600px) {
    .column {
      width: 100%;
    }

    .iframe {
        height:300px;
    }
}

@media all and (min-width: 1400px) {
    .iframe {
        height:200px;
    }
}

@media all and (min-width: 1800px) {
    .iframe {
        height:300px;
    }
}