echarts 面积图颜色渐变

option: {
        title: {
          text: '自来水缴费记录'
        },
        tooltip: {
          trigger: 'axis'
        },
        legend: {
          data: ['小李', '小赵']
        },
        grid: {
          left: '3%',
          right: '4%',
          bottom: '3%',
          containLabel: true
        },
        toolbox: {
          feature: {
            saveAsImage: {}
          }
        },
        xAxis: {
          type: 'category',
          boundaryGap: false,
          data: ['一月', '二月', '三月', '四月', '五月', '六月', '七月']
        },
        yAxis: {
          type: 'value'
        },
        series: [
          {
            name: '小李',
            type: 'line',
            data: [120, 322, 101, 134, 90,20,51],
            areaStyle: {
              color: {
                type: 'linear',
                x: 0,
                y: 0,
                x2: 0,
                y2: 1,
                colorStops: [{
                  offset: 0,  color: '#15ef0e'  // 100% 处的颜色
                }, {
                  offset: 1, color: '#FFFFFF' //   0% 处的颜色
                }],
                global: false // 缺省为 false
              }
            },
            color: '#9aea51', //线条颜色
            smooth: true //线条平滑
          },
          {
            name: '小赵',
            type: 'line',
            data: [220, 182, 191, 234, 290,190,60],
            areaStyle: {
              color: {
                type: 'linear',
                x: 0,
                y: 0,
                x2: 0,
                y2: 1,
                colorStops: [{
                  offset: 0,  color: '#dcc00a'  // 100% 处的颜色
                }, {
                  offset: 1, color: '#FFFFFF' //   0% 处的颜色
                }],
                global: false // 缺省为 false
              }
            },
            color: '#eede5c', //线条颜色
            smooth: true  //线条平滑
          }
        ]
      },