echarts 折線圖陰影顏色漸變

series下面的這個areaStyle

series: [
          {
            data: count,
            type: "line",
            smooth: true,
            areaStyle: { normal: { color: new echarts.graphic.LinearGradient(0, 0, 0, 1, [
                  { offset: 0, color: "red" },
                  { offset: 0.5, color: "pink" },
                  { offset: 1, color: "black" }
                ])
              }
            }, //填充區域樣式
            lineStyle: {
              color: "#00b5ff",
              width: 1
            }, //線條的樣式
            itemStyle: {
              color: "rgb(255, 70, 131)",
              opacity: 0 //為0不會繪制圖形拐點消失
            } //拐點的樣式
          }
        ],

效果圖