class div:
.right {
    position: relative;
    width: 50%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
}

<script>
$(document).ready(function() {
    $("#animate").click(function() {
        $('#content').animate({"left": "50%"},"slow");
        $('#content2').animate({"right": "50%"},"slow");
        $('#container2').removeClass("container-2");
        $('#container2').addClass("container-3");

    });
});
</script>