.container1 {
    position: relative;
    width: 600px;
    height: 460px;
}

.box {
    position: absolute;
}

.box1 {
    width: 215px;
    height: 215px;
    z-index: 3;
    top: 5%;
    left: 5%;
}

.box2 {
    width: 480px;
    height: auto;
    z-index: 1;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.box3 {
    width: 215px;
    height: 215px;
    z-index: 2;
    right: 8%;
    bottom: 5%;
}