body {
    display: flex;
    position: border-box;
    height: 100%;
    width: 100%;
    flex-wrap: wrap;
}

iframe {
    /* grid-column: 1 / 2; */
    /* display: inline-block; */
    width: 25%;
    min-height: 400px;
    flex-grow: 1;
    border-width: 0;
    overflow: hidden;
}