body{
    background-color: #aaa;
}
.box{
    width: 70%;
    height: 200px;
    background: white;
    margin: 40px auto;
}

.effect5{
    position: relative;
}

.effect5:before, .effect5:after{
    z-index: -10;
    position: absolute;
    content: '';
    bottom: 25px;
    left: 10px;
    width: 50%;
    top: 80%;
    max-width: 300px;
    background: #777;

    box-shadow: 0 35px 20px #777;

    transform: rotate(-8deg);

}

.effect5:after{
    transform: rotate(8deg);
    right: 10px;
    left: auto;
}