Paper Page Curl Effect

ul.box {
    position: relative;
    z-index: 1; /* prevent shadows falling behind containers with backgrounds */
    overflow: hidden;
    list-style: none;
    margin: 0;
    padding: 0; 
}
 
ul.box li {
    position: relative;
    float: left;
    width: 250px;
    height: 150px;
    padding: 0;
    border: 1px solid #efefef;
    margin: 0 30px 30px 0;
    background: #fff;
    -webkit-box-shadow: 0 1px 4px rgba(0, 0, 0, 0.27), 0 0 40px rgba(0, 0, 0, 0.06) inset;
    -moz-box-shadow: 0 1px 4px rgba(0, 0, 0, 0.27), 0 0 40px rgba(0, 0, 0, 0.06) inset; 
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.27), 0 0 40px rgba(0, 0, 0, 0.06) inset; 
}
 
ul.box li:before,
ul.box li:after {
    content: '';
    z-index: -1;
    position: absolute;
    left: 10px;
    bottom: 10px;
    width: 70%;
    max-width: 300px; /* avoid rotation causing ugly appearance at large container widths */
    max-height: 100px;
    height: 55%;
    -webkit-box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
    -moz-box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
    -webkit-transform: skew(-15deg) rotate(-6deg);
    -moz-transform: skew(-15deg) rotate(-6deg);
    -ms-transform: skew(-15deg) rotate(-6deg);
    -o-transform: skew(-15deg) rotate(-6deg);
    transform: skew(-15deg) rotate(-6deg); 
}
 
ul.box li:after {
    left: auto;
    right: 10px;
    -webkit-transform: skew(15deg) rotate(6deg);
    -moz-transform: skew(15deg) rotate(6deg);
    -ms-transform: skew(15deg) rotate(6deg);
    -o-transform: skew(15deg) rotate(6deg);
    transform: skew(15deg) rotate(6deg); 
}