.histogram {
    position: relative;
    height:120px;
}


.histogram_content {
    position: relative;
    height: 88px;
    float: left;
}


.histogram_column {
    position: relative;
    float: left;
    height: 88px;
}


.histogram_bar {
    position: absolute;
    background-color: #404040;
    width: 100%;
}


.chart {
    position: absolute;
    top: 0;
    left: 0;
    z-index : 1;
}