.fpgm-wrapper {
    position: relative;
    width: 500px;
    height: 300px;
}
.fpgm-item {
    position: absolute;
    width: 300px;
    height: 200px;
    background: white;
    text-align: center;
    line-height: 200px;
    font-weight: bold;
    box-shadow: 0 0 10px rgba(0,0,0,0.5);
}

/* Add diagonal offset */
.fpgm-item:nth-child(1) { top: 0px; left: 0px; z-index: 5; border: 3px solid red; }
.fpgm-item:nth-child(2) { top: 20px; left: 20px; z-index: 4; border: 3px solid orange; }
.fpgm-item:nth-child(3) { top: 40px; left: 40px; z-index: 3; border: 3px solid yellow; }
.fpgm-item:nth-child(4) { top: 60px; left: 60px; z-index: 2; border: 3px solid green; }
.fpgm-item:nth-child(5) { top: 80px; left: 80px; z-index: 1; border: 3px solid blue; }