.chart_wrap {
    position: relative;
    padding-bottom: 50%;
    height: 50%;
    overflow:hidden;
}

.chart {
    position: absolute;
    top: 0;
    left: 0;
    width:100%;
    height:100%;
}

.chart_wrap2 {
    position: relative;
    height: 50%;
    overflow:hidden;
}