@media only screen and (max-width: 900px) and (min-width: 300px)  {

    header#menu {
    background: #10468b;
    position: relative;
    width: 100%;
    display: inline-block;
}

.flex-box1, .flex-box2, .flex-box3, .flex-box4{
    flex-basis:100%;
    min-width: 100%;
}

.item {
    width: 100%;
    margin: 0;
}

}