echarts实现柱状图在提示阴影中居中

series: [
         {
            // data: vals,
            type: 'bar',
            itemStyle: {
               normal: {
                  color: 'green'
               }
            },
            lineStyle: {
               normal: {
                  color: 'rgba(43, 227, 234, 1)',
               }
            },
            barWidth: '2',
            barGap: '-100%',
    }]